Transcutaneous analyte sensor, applicator thereof, and associated methods

Abstract

Embodiments of the present invention generally relate to systems and methods for measuring an analyte in a subject. More specifically, embodiments of the present invention provide a sensor applicator and method of use with activation, implanting a sensor, removing an insertion needle, engaging a transmitter with a housing, and detaching the applicator from the housing. Systems and methods according to the principles of the present invention allow these steps to occur without significant loss of spring force and without deleterious effects such as seal slingshot.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of October 20, 2016, application number 201680048135.2, and invention name: "Transcutaneous Analyte Sensor, Applicator Thereof, and Associated Methods". Technical Field

[0002] The present invention provides systems and methods for measuring analytes in a subject. More particularly, systems and methods are provided for applying a transcutaneous analyte measurement system to a subject. Background Art

[0003] Diabetes mellitus is a disorder in which the pancreas does not produce enough insulin (type 1 or insulin-dependent) and / or insulin is not effective (type 2 or non-insulin-dependent). In the diabetic state, patients experience high blood sugar levels, which can cause a number of physiological disturbances associated with the deterioration of small blood vessels, such as kidney failure, skin ulcers, or vitreous hemorrhages in the eyes. Hypoglycemic reactions (hypoglycemia) can be caused by an inadvertent overdose of insulin, or after a normal dose of insulin or glucose-lowering agents accompanied by excessive exercise or inadequate food intake.

[0004] Conventionally, people with diabetes carry self-monitoring blood glucose (SMBG) monitors, which typically require an uncomfortable finger-prick method. Due to the lack of comfort and convenience, people with diabetes typically only measure their glucose levels two to four times a day. Unfortunately, these intervals are spread too far apart, so that people with diabetes may discover hyperglycemia or hypoglycemia too late, sometimes resulting in dangerous side effects. Alternatively, glucose levels can be continuously monitored by a sensor system comprising an on-skin sensor assembly. The sensor system can have a wireless transmitter that transmits the measurement data to a receiver that can process and display information based on the measurements.

[0005] The process of applying the sensor to a person is important for this system to be effective and user-friendly. The application process should result in the sensor assembly being attached to the person in a state in which the sensor assembly is able to sense glucose level information, communicate the sensed data to the transmitter, and transmit the glucose level information to the receiver.

[0006] Exemplary prior art systems are disclosed, for example, in US Patent Publication Nos. 2014 / 0088389 and 2013 / 0267813, which are owned by the assignee of the present application and are incorporated herein by reference in their entirety. These systems often rely on specific configurations of springs and seals. These configurations result in certain disadvantages. For example, movement occurs when the spring is at its lowest force, such as at the extremes of its extension or compression, i.e., at its equilibrium position. Furthermore, while the spring is maintained in a compressed or extended, or otherwise preloaded, condition, between the time of manufacture and the time of activation, the spring may experience mechanical fatigue. This can also lead to mechanical "creep," particularly in plastic components.

[0007] Other issues include the "slingshotting" of certain components, particularly seals, as the insertion element undergoes movement caused by the insertion routine. These effects lead to inaccurate sensor line placement because the amount of slingshot is unpredictable. Additionally, where a single spring is shown in previous embodiments, it would generally have to be large to accommodate all the movement required in insertion and retraction, and this large spring could be expected to cause detrimental tissue trauma as the needle and sensor are forcefully inserted into the body.

[0008] This background is provided to introduce a brief context for the following summary and detailed description. This background is not intended to help determine the scope of the claimed subject matter, nor to limit the claimed subject matter to implementations that solve any or all of the disadvantages or problems presented above. Summary of the Invention

[0009] The present systems and methods relate to systems and methods for measuring an analyte in a subject and for applying a transcutaneous analyte measurement system to a subject. Various embodiments of the present systems and methods for applying an analyte measurement system have several features, no single one of which is solely responsible for the desirable properties of the features. Without limiting the scope of the embodiments of the present invention as expressed by the appended claims, the more salient features of the embodiments will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description of the Invention," one will understand how the features of the embodiments of the present invention provide the advantages described herein.

[0010] In a first aspect, an applicator for applying an on-skin sensor assembly to the skin of a subject is provided, the device comprising: an applicator housing configured to secure a disposable housing, wherein the disposable housing is configured to receive an electronics unit, and wherein the electronics unit is configured to generate analyte information based on a signal from a sensor, the sensor comprising a sensor wire having an electrode contact portion, the electrode contact portion being configured for powering the sensor and transmitting the signal from the sensor to the electronics unit when the electronics unit is received in the disposable housing; and a sensor insertion actuator configured to insert a retention portion of the sensor wire into the skin of a subject. The sensor wire is inserted into the subject and the disposable housing is mounted to a portion of the sensor wire and a non-retained electrode portion, the retaining portion of the sensor wire being inserted into the subject's skin using a needle, the needle being configured to provide support and structure to the sensor wire during insertion, the sensor insertion drive being configured to perform an insertion step in which the needle is inserted into the subject's skin to deploy the sensor wire, and a retraction step in which the needle is retracted from the subject's skin, leaving the sensor wire deployed in the subject, and wherein the needle insertion step and the needle retraction step are performed so as to provide a predetermined force distribution during the needle insertion and retraction steps.

[0011] Embodiments of the embodiments may include one or more of the following. The predetermined force distribution during the needle insertion step may be defined by an equation such that F=f(x), where x is the distance the sensor wire is translated from the initial position. The function f(x) may be defined as an envelope between ax2+bx+c and dx2+gx+h. The function f(x) may be a bimodal curve. The sensor insertion drive may include a crank slider assembly, a rack and pinion assembly, or a barrel cam. The applicator may further include a trigger configured to cause an insertion assembly (e.g., a needle and / or cannula) to insert the sensor into the body in response to being activated. A needle may be employed to provide breaking strength to the sensor (e.g., sensor wire), and a cannula may be employed to provide breaking strength to the needle. The trigger may be an activatable button configured to be operated by a user, such as a button mechanically linked to the insertion assembly, such that activation of the button forms part of the insertion step or the retraction step or both.

[0012] A spring may be used to perform the insertion step, and activation of the button may perform the retraction step. The spring may be a torsion spring. Activation of the button may perform the insertion step, and the spring may perform the retraction step. Activation of the button may comprise depressing a plunger. The trigger may be an electromechanical element configured to be activated by a signal received from a transmitter. The transmitter may comprise a smartphone running an insertion application. The insertion assembly may further comprise a cannula to provide additional breaking strength and isolation to the needle, wherein the cannula is disposed within and passes through at least one seal in the housing during the insertion step, and wherein the cannula is configured to be removed from the seal and the housing as part of the retraction step.

[0013] The sensor insertion drive may include a primary operating component and a power assist component, such that the power assist component is configured to insert additional stored energy into the primary operating component to remove the cannula from the seal and housing during the retraction step. The power assist component may be a power assist spring. The housing may define at least one hole for passage of the sensor wire, and the seal may be configured to substantially isolate the retained portion of the sensor wire from the unretained portion of the sensor wire. The applicator may further include a seal carrier in which at least one seal is positioned, wherein the seal is attached to the seal carrier, including by overmolding or gluing. The seal carrier may include sidewall ribs to reduce seal deformation during cannula removal. The seal carrier may include a spring coupling to the seal to reduce seal deformation during cannula removal. The seal may be coupled to the seal carrier to inhibit movement of the seal during cannula removal. The seal or the seal carrier or both may define a cavity configured to reduce friction between the seal or the seal carrier and the cannula during cannula removal.

[0014] At least two pucks may be positioned within the housing to electrically couple areas of the electrode contact portion to corresponding electrodes on the electronics unit, and the pucks may be configured to reduce friction between the seal or seal carrier and the cannula, the friction-reducing configuration being defined by a shaved or hollowed portion of the puck or by a cavity within the puck.

[0015] The seal can be a hybrid seal comprising silicone and TPE. The seal can be a stack seal, wherein the stack seal is configured to decouple movement of the sensor wire from movement of the cannula. The seal can be a sandwich seal, and the sandwich seal can include a first sealing component and a second sealing component, wherein the cannula is disposed between the first and second sealing components. The seal can be a flow seal, wherein the flow seal defines a channel through a channel wall, the cannula is disposed in the channel, and can further include a lubricant disposed between the channel wall and the exterior of the cannula. The seal can be an O-ring seal.

[0016] The applicator may further include a seal support, wherein the seal support is configured to inhibit movement of the seal during removal of the cannula. The seal support may be a spring. The applicator may further include a sensor wire support, wherein the sensor wire support is configured to inhibit movement of the sensor wire during removal of the cannula. The sensor wire support may be a spring. The applicator may further include a motor rotationally coupled to the cannula, such that the motor is configured to rotate the cannula before and during removal of the cannula. The applicator may further include a cam rotationally coupled to the cannula, such that the cam is configured to rotate the cannula before and during removal of the cannula, the cam being coupled to the insertion assembly and receiving a linear force therefrom. The linear force may be received from a spring. The linear force may be received from user activation of a button. The cam may be configured to rotate the cannula with a cycle time of less than 500ms.

[0017] The insertion assembly can be configured to retract the cannula before the retraction of the needle so that the slingshot effect of the flexible seal causes the seal to hit the needle instead of the sensor wire. During the insertion step, the insertion assembly can be configured to deploy the needle to a first depth and then deploy the sensor wire to a second depth, wherein the second depth is deeper than the first depth. The applicator can further include an electronics unit placement spring, which is configured to snap the electronics unit into the housing during the retraction step. The electronics unit placement spring can be configured to pull the electronics unit into the housing. The housing can be configured to fasten the electronics unit by mechanical connection to the electronics unit bay, and the electronics unit and the electronics unit bay can be configured so that the electronics unit cannot be removed from the electronics unit bay without destroying a part of the electronics unit bay, the destruction also destroying the mechanical connection. The electronics unit can be configured to generate analyte information in response to the trigger being activated and / or the sensor being electrically connected to the electronics unit. The housing can be configured so that the electronics unit cannot be removed from the housing while the housing is attached to the skin of the subject.

[0018] The time between the sensor being inserted into the body and the electronics unit being secured to the housing can be less than about 1 second. At least one contact on the electronics unit can be more rigid than the sensor, and the electronics unit can be configured such that when fully secured to the housing, the at least one contact presses the sensor into the elastomeric seal such that the elastomeric seal is compressed and conforms to the sensor.

[0019] The sensor may be configured to be surrounded by the elastomeric seal after insertion into the body, and the electronics unit may be configured to compress the elastomeric seal to secure the sensor and form a seal around the sensor in response to the electronics unit being released from the lock.

[0020] The device may be configured to disengage from the housing and the electronics unit in response to the electronics unit being released from the lock. The device may be configured to provide one or more tactile, audible, or visual indications that the electronics unit has been inserted into the housing to the extent permitted by the lock. The applicator may further include a trigger lock configured to prevent activation of the trigger. The applicator may further include a protective cover configured to cover the electronics unit and the housing after the sensor is inserted and to secure the electronics unit to the housing.

[0021] In a second aspect, a device for applying an on-skin sensor assembly to a subject is provided, comprising: a needle containing a removable sensor, the sensor comprising a sensor wire having at least two conductive contacts at an extracorporeal portion and a sensing portion at an intracorporeal portion, the needle configured to be inserted into the subject to deploy the sensor, including being inserted into the subject to deploy the sensing portion in vivo in the subject, and wherein the needle is configured to be retracted from the subject after deployment; a cannula traversing a seal within a disposable housing, wherein the needle is configured to be inserted into the subject after at least partially passing through the cannula in a first direction when deploying the sensor in the subject, and wherein the needle is configured to at least partially pass through the cannula in a direction opposite to the first direction when the needle is being retracted from the subject, and wherein the cannula is configured to be at least partially retracted from the seal during the time the needle is being retracted from the subject; wherein the needle insertion and retraction require a first portion of a force distribution, and wherein cannula retraction requires a second portion of the force distribution; and further comprising one or more drive components to provide or achieve a force exceeding the force distribution during both the first portion and the second portion.

[0022] Embodiments of the embodiments may include one or more of the following. One or more of the drive assemblies may convert the rotational force into a linear force. The drive assembly may be a scotch yoke, a crank slider, a barrel cam, or a rack and pinion. The drive assembly for the first portion of the force distribution may be a scotch yoke, a crank slider, a barrel cam, or a rack and pinion, and the drive assembly for the second portion of the force distribution may be a spring. The energy source for the rotational force may be a torsion spring. The spring may be configured to store energy for the second portion of the force distribution by compression or extension. Needle retraction may cause the cannula to retract. The second portion may have a maximum value that is greater than the maximum value of the first portion. The first and second portions may be normal curves.

[0023] The disposable housing may further comprise a diaphragm through which the sensor wire passes, and wherein the diaphragm provides a force to the sensor wire that resists removal from the body. The first and second parts together may form a bimodal distribution. The one or more drive assemblies may comprise a first coil spring configured to perform a first part of the force distribution, and a second coil spring configured to perform a second part of the force distribution. The drive assembly for the first part of the force distribution may be a scotch yoke coupled to a torsion spring, and the drive assembly for the second part of the force distribution may be a spring, wherein the device is configured such that when the movement corresponding to the first part of the force distribution is completed, the wheel of the scotch yoke is prevented from any further rotation. Any further rotation of the wheel of the scotch yoke forward or backward may be prevented. The applicator may further comprise a ratchet assembly, wherein the wheel of the scotch yoke is prevented from any further rotation due to the ratchet assembly.

[0024] The seal carrier may include one or more elements configured to prevent slingshot of the seal when the cannula is retracted. The one or more elements may include a rib mounted to the seal carrier and penetrating at least a portion of the seal.

[0025] The seal may be a hybrid seal. The hybrid seal may include a first component having a first durometer hardness and a second component having a second durometer hardness that is higher than the first durometer hardness. The material of the first component may be a thermoplastic elastomer, and the material of the second component may be silicone. The seal may define a void volume that at least partially surrounds the cannula before the cannula is retracted, and the seal may be configured such that the void volume can be at least partially filled with a lubricant, such as petroleum jelly.

[0026] The seal may be configured to define an injection port for lubricant, the injection port being in pressure communication with the void volume. The void volume may be generally cuboid in shape. The seal may further define two puck cavities, the puck cavities being generally cylindrical in shape, and the device may further comprise two pucks, the pucks being generally cylindrical in shape, each puck occupying one of the puck cavities, and the cannula may be positioned so as to traverse each puck prior to cannula retraction. The puck cavities may be defined by cored sections of the pucks.

[0027] In a third aspect, a device is provided for placing a sensor within a disposable housing, the sensor not being pre-connected to the disposable housing, the device comprising: a needle configured to accommodate an implantable sensor configured to be placed in a body, the sensor being comprised of a wire and having a proximal end and a distal end, the sensor being held against movement in one direction by a push rod when placed in the needle; an applicator in which the needle is positioned, the applicator comprising at least one latch; a drive member positioned within the applicator to insert the needle into the body and to retract the needle after insertion; wherein at the distal end of the needle's travel, the push rod engages the latch to maintain the push rod in a stationary position during needle retraction, such that the distal end of the sensor is placed in the body and the proximal end of the sensor is placed in the disposable housing.

[0028] Embodiments of the embodiments may include one or more of the following. The applicator may further include a cannula, and the device may be configured such that the needle at least partially advances through the cannula during at least a portion of insertion and retraction. The cannula may be located within a disposable housing. The drive member may be configured to remove the cannula during retraction of the needle. The drive member may include, for example, a torsion spring or a booster spring, and the booster spring may be configured to perform retraction. The drive member may further include a rack and pinion, a crank slider, a barrel cam, or any other suitable mechanism for converting rotational motion into linear motion. The sensor may be further retained to resist movement in the needle in two directions by the definition of a kink in the sensor, wherein the kink provides a frictional contact point between the inner wall of the needle and the sensor, such as one or more wires that constitute the sensor in one embodiment.

[0029] The device may further include a seal in a disposable housing such that the proximal end of the sensor is disposed in the seal in the disposable housing after insertion and retraction. The sensor wire may be a coaxial wire having a first exposed portion and a second exposed portion. The seal may define two cavities and may further include first and second conductive pucks, each puck disposed in a respective cavity such that the first conductive puck is in signal communication with the first exposed portion when the sensor wire is inserted into the seal, and such that the second conductive puck is in signal communication with the second exposed portion when the sensor wire is inserted into the seal. The applicator may further include a seal carrier in which the seal is disposed. The applicator may further include a push rod return spring configured to bias the push rod during movement of the push rod, thereby removing ambiguity in the movement of the push rod.

[0030] In a fourth aspect, a wearable portion of a device for monitoring an analyte is provided, comprising: a disposable housing in which a seal carrier can be positioned, the seal carrier being configured to support at least one seal and connected to at least one implantable sensor wire; and a transmitter configured to frictionally or mechanically couple to the disposable housing, the transmitter being configured to conductively couple to a proximal portion of the sensor wire; wherein the disposable housing further comprises a frangible portion such that once the transmitter is frictionally or mechanically coupled to the disposable housing, the transmitter cannot be removed without removing the frangible portion. In other words, once the frangible portion is removed, the transmitter can no longer be secured to the disposable housing, and a new disposable housing must be employed.

[0031] Example implementations may include one or more of the following: The frangible portion may form an outer perimeter of the seal carrier, and the transmitter may be inserted adjacent to the outer perimeter.

[0032] In a fifth aspect, a device is provided for placing a sensor within a disposable housing, the sensor not being pre-connected to the disposable housing, the device comprising: a needle configured to receive an implantable sensor configured to be placed in a body, the needle passing through a seal, the sensor being comprised of a wire and having a proximal end and a distal end, the sensor being held against movement in one direction by a push rod when placed in the needle; an applicator in which the needle is located; a drive member located within the applicator to insert the needle into the body and to retract the needle after insertion; and a spring configured to engage the sensor wire at least when the needle is removed, such that after removal of the needle and push rod, the sensor wire is secured against movement caused by movement of the needle through the seal.

[0033] Numerous advantages can be seen by implementing arrangements according to the principles of the present invention. For example, embodiments result in consistent insertion, retraction, and speed, which in turn leads to more reproducible sensor environments and in vivo wound responses. This, in turn, can reduce sensor-to-sensor performance variability, including the effects of outliers, immersion and recovery errors, and end-of-life errors. This further enables reduced factory calibration, including more predictable signal trends at startup, and reduced pain for the patient.

[0034] As an example, faster insertion and retraction steps reduce the likelihood of user movement while the needle and / or deployment mechanism is in the body. While it has been found that the time required for a user to react to pain is approximately 0.40 to 1.0 seconds, systems and methods according to the principles of the present invention can insert and retract the needle in, for example, 0.25 seconds, such that the needle has exited the skin before the user can begin to react. Systems and methods according to the principles of the present invention further prevent variability in the needle / sensor angle due to user movement. Additionally, systems and methods according to the principles of the present invention reduce the likelihood of tissue damage and pain due to, for example, movement perpendicular to the needle axis that may be caused by user movement.

[0035] In one aspect, an applicator for applying an on-skin sensor assembly to a subject's skin includes an applicator housing operatively coupled to a disposable housing, the disposable housing being configured to receive an electronics unit configured to generate analyte information based on a signal from the sensor. The applicator further includes an insertion assembly comprising an insertion member configured to insert the sensor into the subject's skin; a resistance member releasably coupled to the insertion assembly; a first drive assembly containing a first amount of stored energy, the first drive member being configured to drive the insertion member in a distal direction to an insertion position; and a second drive assembly containing a second amount of stored energy. The second drive member is configured to drive the insertion member in a proximal direction, and the second amount of stored energy is sufficient to decouple the resistance member from the insertion assembly. In one embodiment, the first drive assembly is configured to drive the insertion member in the proximal direction after the insertion member reaches the insertion position. In another embodiment, the first drive assembly is configured to activate the second drive assembly after the first drive assembly begins driving the insertion member in the proximal direction. In another embodiment, the first drive assembly is configured to activate the second drive assembly when the first drive assembly reaches a trigger position, the trigger position being proximal to the insertion position. In another embodiment, the second drive assembly is configured to decouple the resistance component from the insertion assembly. In another embodiment, the second amount of stored energy is sufficient to decouple the resistance component from the insertion assembly. In another embodiment, the second amount of stored energy is sufficient to decouple the resistance component from the insertion assembly and drive the insertion component in a proximal direction to the retracted position. In another embodiment, the proximal direction and the distal direction extend along the axis of the insertion component. In another embodiment, the proximal direction and the distal direction extend at an angle to the plane of the disposable shell. In another embodiment, the resistance component is operatively coupled to the disposable shell. In another embodiment, the resistance component is frictionally engaged with the insertion assembly. In another embodiment, the resistance component is slidably coupled to the insertion assembly. In another embodiment, the resistance component comprises an elastomer. In another embodiment, the resistance component comprises a seal. In another embodiment, the applicator further comprises a carrier operatively coupled to the disposable housing, the resistance member being operatively coupled to the carrier. In another embodiment, the carrier is removably coupled to the disposable housing. In another embodiment, the insertion member comprises a needle. In another embodiment, the insertion assembly comprises a cannula. In another embodiment, the insertion member is configured to advance through the cannula when the insertion member is moved distally. In another embodiment, the resistance member is releasably coupled to the cannula.In another embodiment, the cannula is fixed relative to the disposable housing when the insertion member is moved distally. In another embodiment, the seal comprises a first portion and a second portion, the first portion having a first durometer hardness and the second portion having a second durometer hardness, the second durometer hardness being higher than the first durometer hardness. In another embodiment, the first portion comprises silicone and the second portion comprises TPE. In another embodiment, the cannula is disposed between the first and second sealing components. In another embodiment, the resistance member defines a channel configured to receive a fluid or gel. In another embodiment, the applicator further comprises a cam configured to rotate the cannula about the axis of the cannula. In another embodiment, the distal end of the insertion member extends toward the distal end of the cannula when the resistance member is decoupled from the insertion assembly. In another embodiment, the resistance member comprises a contact surface configured to engage the cannula, the contact surface defining one or more cavities between the contact surface and the cannula. In another embodiment, the applicator further comprises a plurality of conductive elastomeric contacts disposed within the resistance member, the conductive elastomeric contacts defining one or more cavities between the contact surface and the cannula. In another embodiment, at least a portion of the insertion assembly extends through the two conductive elastomeric contacts. In another embodiment, the resistance component includes a contact surface configured to engage the cannula, and wherein the conductive elastomeric contacts define one or more cavities between the contact surface and the cannula. In another embodiment, the resistance component is directly coupled to the insertion component. In another embodiment, the insertion assembly includes a support member configured to inhibit proximal movement of the sensor at least after the insertion assembly reaches the insertion position. In another embodiment, the support member includes a push rod. In another embodiment, the support member includes a spring. In another embodiment, the disposable housing includes a first portion coupled to a second portion via a frangible member. In another embodiment, the disposable housing includes a receptacle configured to receive a corresponding key of a compatible electronic device unit. In another embodiment, the disposable housing includes an interference structure configured to prevent installation of an incompatible electronic device unit in the disposable housing. In another embodiment, the applicator further includes a trigger configured to activate the first drive assembly. In another embodiment, the trigger comprises an electromechanical element configured to be activated by a signal received from a transmitter. In another embodiment, the transmitter comprises a smartphone running an insertion application. In another embodiment, the applicator further comprises a safety lock configured to prevent operation of the trigger. In another embodiment, the safety lock comprises a tab coupled to the trigger via at least one frangible component.In another embodiment, the first amount of stored energy exceeds approximately 1 / 4 lbf, and the second amount of stored energy exceeds approximately 1 / 8 lbf. In another embodiment, at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion into linear motion. In another embodiment, at least one of the first drive assembly and the second drive assembly includes a scotch yoke, a crank slider, a barrel cam, or a rack and pinion. In another embodiment, at least one of the first drive assembly and the second drive assembly includes a spring. In another embodiment, at least one of the first drive assembly and the second drive assembly includes a torsion spring. In another embodiment, the second amount of stored energy is greater than the first amount of stored energy. In another embodiment, the applicator further includes a ratchet component configured to prevent reverse driving of the first drive assembly. In another embodiment, the sensor includes a sensor wire. In another embodiment, the resistance component is configured to substantially isolate a first portion of the sensor wire from a second portion of the sensor wire. In another embodiment, the disposable housing defines at least one opening configured to allow the sensor to pass through. In another embodiment, the carrier includes a fastening member configured to inhibit proximal movement of the resistance member. In another embodiment, the fastening member includes glue. In another embodiment, the fastening member includes one or more inwardly extending ribs. In another embodiment, the fastening member includes a spring. In another embodiment, the disposable housing is configured such that the electronics unit cannot be removed from the disposable housing once installed while the housing is attached to the skin of the subject. In another embodiment, the disposable housing is configured such that the electronics unit cannot be removed from the disposable housing once installed without destroying the fragile member. In another embodiment, the sensor includes a bend configured to frictionally engage with the insertion member. In another embodiment, the insertion assembly includes a needle hub, a cannula, and a cannula hub, and wherein the engagement of the needle hub with the cannula hub causes the cannula to move in a proximal direction.

[0036] In another aspect, an applicator for applying an on-skin sensor assembly to a subject's skin includes an applicator housing operatively coupled to a disposable housing, the disposable housing configured to receive an electronics unit configured to generate analyte information based on a signal from the sensor. The applicator further includes an insertion assembly comprising an insertion member configured to insert the sensor into the subject's skin; a first drive assembly containing a first amount of stored energy, the first drive member configured to drive the insertion member in a distal direction during a first phase and in a proximal direction during a second phase; and a second drive assembly containing a second amount of stored energy, the second drive member configured to drive the insertion member in a proximal direction. The first drive assembly is configured to activate the second drive assembly during the second phase. In one embodiment, the drive assembly is self-reversing from the first phase to the second phase. In another embodiment, the distal end of the insertion member extends toward the distal end of the cannula during the second phase. In another embodiment, the first drive assembly is configured to drive the insertion member in the proximal direction after the insertion member reaches an insertion position. In another embodiment, the first drive assembly is configured to activate the second drive assembly during the second phase. In another embodiment, the first drive assembly is configured to activate the second drive assembly in response to the first drive assembly reaching a trigger position during the second phase. In another embodiment, the applicator further includes a resistance component that is operatively coupled to the insertion assembly during the first phase, wherein the second drive assembly is configured to decouple the resistance component from the insertion assembly during the second phase. In another embodiment, the second amount of stored energy is sufficient to decouple the resistance component from the insertion assembly. In another embodiment, the insertion assembly includes a cannula. In another embodiment, the insertion component is configured to advance through the cannula during the first phase. In another embodiment, the resistance component is releasably coupled to the cannula. In another embodiment, the cannula is fixed relative to the disposable housing when the insertion component moves distally. In another embodiment, at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion into linear motion. In another embodiment, at least one of the first drive assembly and the second drive assembly comprises a scotch yoke, a crank slider, a barrel cam, or a rack and pinion. In another embodiment, at least one of the first drive assembly and the second drive assembly comprises a spring. In another embodiment, at least one of the first drive assembly and the second drive assembly comprises a torsion spring. In another embodiment, the second amount of stored energy is greater than the first amount of stored energy.In another embodiment, the applicator further comprises a ratchet member configured to prevent back driving of the first drive assembly.

[0037] In another aspect, a sensor inserter assembly for applying an on-skin device to the skin of a subject, the assembly comprising: an applicator body; a disposable housing releasably coupled to the applicator body; a prong configured to place a sensor at least partially into the skin of the subject; a resistance member operatively coupled to the disposable housing; a separation member releasably coupled to the resistance member, the separation member configured to prevent contact between the prong and the resistance member; a deployment assembly configured to cause the prong to move from a proximal starting position to a distal insertion position during a first phase and then to a proximal retracted position during a second phase, the deployment assembly further configured to release the separation member from the resistance member during the second phase; a first stored energy component storing sufficient energy to drive the first phase and at least a first portion of the second phase; and a second stored energy component storing sufficient energy to drive at least a second portion of the second phase. In one embodiment, the second stored energy component stores sufficient energy to drive the second phase. In another embodiment, the second stored energy component stores more energy than the first stored energy component. In another embodiment, the disposable housing is configured to automatically release from the applicator body after the separation member is released from the resistance member. In another embodiment, the disposable housing is configured to automatically release from the applicator body in response to the separation member being released from the resistance member. In another embodiment, the resistance member is movable relative to the disposable housing at least after the separation member is released from the resistance member. In another embodiment, the deployment assembly is self-reversing from the first stage to the second stage. In another embodiment, the deployment assembly is configured to activate the second stored energy component during the second stage. In another embodiment, the separation member is frictionally engaged with the resistance member. In another embodiment, the separation member is slidably coupled to the resistance member. In another embodiment, at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion into linear motion.

[0038] In another aspect, a method for applying an on-skin sensor assembly to a subject's skin includes providing an assembly comprising: an applicator housing operatively coupled to a disposable housing; an insertion assembly comprising an insertion member; a first drive assembly containing a first amount of stored energy; and a second drive assembly containing a second amount of stored energy. The method further includes activating a trigger of the assembly, wherein activating the trigger causes the first drive assembly to drive the insertion member in a distal direction during a first phase, wherein the sensor is inserted into the subject's skin, causing the first drive assembly to drive the insertion member in a proximal direction during a second phase, wherein the first drive assembly activates the second drive assembly during the second phase, causing the second drive assembly to drive the insertion member in a proximal direction during the second phase. In one embodiment, the method further includes installing an electronics unit in the disposable housing, the electronics unit configured to generate analyte information based on a signal from the sensor. In another embodiment, the assembly further includes a resistance member coupled to the insertion assembly. In another embodiment, activating the trigger causes the second drive member to decouple the resistance member from the insertion assembly during the second phase. In another embodiment, the second amount of stored energy is sufficient to decouple the resistance member from the insertion assembly. In another embodiment, the resistance member includes a seal. In another embodiment, the insertion assembly includes a cannula. In another embodiment, the second amount of stored energy is greater than the first amount of stored energy. In another embodiment, at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion into linear motion. In another embodiment, the first drive assembly activates the second drive assembly during the second phase in response to the first drive assembly reaching a trigger position.

[0039] In further aspects and embodiments, the above method features of various aspects are formulated in aspects of a system having an applicator configured to perform the method features, as in the various aspects. Any feature of any aspect of the embodiment, including but not limited to any embodiment of any of the first through fifth aspects mentioned above, is applicable to all other aspects and embodiments described herein, including but not limited to any embodiment of any of the first through fifth aspects mentioned above. Moreover, any feature of any aspect of the embodiment, including but not limited to any embodiment of any of the first through fifth aspects mentioned above, may be independently combined in any manner with other embodiments described herein, in part or in whole, for example, one, two, or three or more embodiments may be combined in whole or in part. Furthermore, any feature of any aspect of the embodiment, including but not limited to any embodiment of any of the first through fifth aspects mentioned above, may be optional with respect to other aspects or embodiments. Any aspect or embodiment of the method may be performed by a system or device of another aspect or embodiment, and any aspect or embodiment of the system or device may be configured to perform the method of another aspect or embodiment, including but not limited to any embodiment of any of the first through fifth aspects mentioned above.

[0040] This Summary is provided to introduce a series of concepts in a simplified form. The concepts are further described in the Detailed Description section. Elements or steps other than those described in this Summary are possible, and no element or step is necessarily required. This Summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter. The claimed subject matter is not limited to embodiments that address any or all of the shortcomings mentioned in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] These and other features, aspects and advantages are described below with reference to the accompanying drawings, which are intended to illustrate rather than limit the present invention. In the accompanying drawings, like reference characters consistently denote corresponding features throughout similar embodiments.

[0042] Figure 1 is a schematic diagram of a continuous analyte sensor system attached to a subject and in communication with other devices.

[0043] Figure 2 The force distribution curve for sensor insertion is shown.

[0044] Figure 3 A partially exploded view of an applicator configured in accordance with an embodiment is illustrated.

[0045] Figure 4 Another force profile for sensor insertion is shown.

[0046] Figure 5A schematic diagram of components of an applicator according to an embodiment is illustrated.

[0047] Figure 6 The diagram shows Figure 3 Another partially exploded view of an applicator of an embodiment configuration.

[0048] Figure 7 Pictured Figure 3 and 6 An exploded perspective view of the needle hub assembly of the applicator.

[0049] Figure 8 Pictured Figure 3 and 6 A cross-sectional perspective view of the needle hub assembly of an applicator.

[0050] Figure 9 Pictured Figure 3 and 6 Perspective view of the cannula hub of the applicator.

[0051] Figure 10 Pictured Figure 3 and 6 A cross-sectional side view of certain components of the applicator.

[0052] Figure 11 Pictured Figure 3 and 6 A perspective view of the pusher hub of the applicator.

[0053] Figure 12 Pictured Figure 3 and 6 A perspective view of an applicator with the upper housing removed for illustration purposes.

[0054] Figure 13 The diagram shows Figure 3 and 6 A perspective view of the applicator's cannula hub engaging the internal needle hub.

[0055] Figure 14 The diagram shows Figure 3 and 6 A cutaway perspective view of the needle hub assembly of an applicator engaging the pusher hub.

[0056] Figure 15 Pictured Figure 3 and 6 A top view of an applicator of FIG. 1 with the upper housing removed for illustration purposes and with the torsion spring housing in a first configuration.

[0057] Figure 16 Pictured Figure 3 and 6Another top view of the applicator of with the upper housing removed for illustration purposes and with the torsion spring housing in a second configuration.

[0058] Figure 17 One way of coupling sensor wires to contacts is illustrated according to one embodiment.

[0059] Figure 18 The diagram shows the sensor wires and Figure 17 Side view of the spring coupling.

[0060] Figure 19 Pictured Figure 17 Another side view of the spring.

[0061] Figure 20 A perspective view illustrating another arrangement of a sensor inserted into a driver according to an embodiment is shown.

[0062] Figure 21 Illustrated is a schematic perspective view of another applicator according to an embodiment, with upper and lower housings removed for illustration purposes.

[0063] Figure 22 Pictured Figure 21 Force distribution curve of the applicator with sensor insertion.

[0064] Figure 23 Pictured Figure 21 Another perspective view of the applicator.

[0065] Figure 24A 、 24B , 24C and 24D illustrate Figure 21 The action steps of the applicator.

[0066] Figure 25 Illustrated is a schematic perspective view of another applicator configured in accordance with an embodiment, with the upper housing removed for illustration purposes, and with the drive member in a first configuration.

[0067] Figure 26 Pictured Figure 25 Another schematic perspective view of an applicator of with the upper and lower housings removed for illustration purposes and with the drive member in a second configuration.

[0068] Figure 27 Illustrated is a schematic perspective view of another applicator configured in accordance with an embodiment.

[0069] Figure 28 A cross-sectional perspective view of another applicator configured in accordance with an embodiment is illustrated with upper and lower housings removed for illustration purposes.

[0070] Figure 29A cross-sectional side view of another applicator configured in accordance with an embodiment is illustrated with upper and lower housings removed for illustration purposes.

[0071] Figure 30 The force profile of sensor insertion for a manual insertion applicator is shown.

[0072] Figure 31 is a flow chart of steps for sensor insertion according to an embodiment.

[0073] Figure 32 Illustrated is a schematic perspective view of a drive mechanism of an applicator configured in accordance with an embodiment.

[0074] Figure 33 Illustrated is a schematic perspective view of another drive mechanism for an applicator configured in accordance with an embodiment.

[0075] Figure 34 Illustrated is a schematic perspective view of another drive mechanism for an applicator configured in accordance with an embodiment.

[0076] Figure 35 Illustrated is a step in a method for deploying a sensor into the skin of a patient, according to an embodiment.

[0077] Figure 36 Illustrated is another step in a method for deploying a sensor into the skin of a patient according to an embodiment.

[0078] Figure 37 A flow chart illustrating steps of sensor insertion according to another embodiment is shown.

[0079] Figure 38A to C Illustrated are the steps of needle deployment through a cannula according to one embodiment.

[0080] Figure 39 Illustrated is a perspective view of a disposable housing and seal carrier configured in accordance with an embodiment.

[0081] Figure 40 Illustrated is a side view of a transmitter inserted into a disposable housing according to an embodiment.

[0082] Figure 41 Illustrated is a perspective view of a transmitter configured in accordance with an embodiment.

[0083] Figure 42 A partial cross-sectional side view of an applicator configured in accordance with an embodiment is illustrated with the cannula hub in a distal position.

[0084] Figure 43 Pictured Figure 42 Partial cross-sectional side view of an applicator with the cannula hub in a retracted position.

[0085] Figure 44 Pictured Figure 40 A cross-sectional perspective view of a disposable housing with the seal carrier in a first orientation.

[0086] Figure 45 Pictured Figure 44 Detail view of a part of.

[0087] Figure 46 Pictured Figure 40 A cross-sectional perspective view of a disposable housing with the seal carrier in a second orientation.

[0088] Figure 47 Pictured Figure 40 A perspective view of a disposable housing with the rupture section removed to facilitate removal of the transmitter.

[0089] Figure 48 Pictured Figure 40 A cross-sectional perspective view of the disposable housing and launcher further illustrates the rupturable feature of the disposable housing.

[0090] Figure 49A Illustrated is a cross-sectional perspective view of a seal configured in accordance with an embodiment.

[0091] Figure 49B Pictured Figure 49A Cross-sectional side view of the seal.

[0092] Figure 49C Pictured Figure 49A A perspective view of the seal.

[0093] Figure 50 A cored puck configured in accordance with an embodiment is illustrated.

[0094] Figure 51 Illustrated is a cross-sectional perspective view of a hybrid seal configured in accordance with an embodiment.

[0095] Figure 52 Pictured Figure 51 Another perspective view of the hybrid seal.

[0096] Figure 53 Pictured Figure 51 Cross-sectional end view of a hybrid seal.

[0097] Figure 54 Pictured Figure 51 A bottom perspective view of a hybrid seal.

[0098] Figure 55 Pictured Figure 51 End view of the hybrid seal.

[0099] Figure 56 Pictured Figure 51 Cross-sectional side view of a hybrid seal.

[0100] Figures 57A to C Illustrated are cross-sectional side views of a flow seal at various stages of needle and grease insertion configured in accordance with an embodiment.

[0101] Figure 58 Illustrated is a schematic end view of the flow seal of Figure 57 installed within a seal carrier.

[0102] Figure 59 Illustrated is a perspective view of the flow seal of Figure 57 installed within a seal carrier.

[0103] Figure 60 Illustrated is a perspective view of an annular seal configured in accordance with an embodiment.

[0104] Figure 61 Pictured Figure 60 A top view of the annular seal.

[0105] Figure 62 The diagram shows the Figure 61 The line 62-62 is intercepted Figure 60 Cross-sectional side view of an annular seal.

[0106] Figure 63 A bottom perspective view of a seal carrier configured in accordance with an embodiment is illustrated.

[0107] Figure 64 Pictured Figure 63 A top perspective view of a seal carrier with a sandwich seal installed in the seal carrier.

[0108] Figure 65 Pictured Figure 64 Another perspective view of the seal carrier and sandwich seal.

[0109] Figure 66 Illustrated is a perspective view of a seal carrier and sandwich seal configured in accordance with another embodiment.

[0110] Figure 67 Pictured Figure 66 End view of the seal carrier and sandwich seal.

[0111] Figure 68 Pictured Figure 66 Side view of a seal carrier and a sandwich seal, wherein the sandwich seal is installed in the seal carrier.

[0112] Figure 69 Pictured Figure 66Another side view of a seal carrier and a sandwich seal mounted in the seal carrier.

[0113] Figure 70 Illustrated is a perspective view of a stack seal configured in accordance with an embodiment.

[0114] Figure 71 Pictured Figure 70 Cross-sectional end view of a stack seal.

[0115] Figure 72 Pictured Figure 70 Another perspective view of a stacked seal shown coupled to a cannula.

[0116] Figure 73 One method of performing sensor wire capture in a seal carrier according to an embodiment is illustrated.

[0117] Figure 74 Another method of performing sensor wire capture in a seal carrier according to another embodiment is illustrated.

[0118] Figure 75 Another method of performing sensor wire capture in a seal carrier according to another embodiment is illustrated.

[0119] Figure 76 Another method of performing sensor wire capture in a seal carrier according to another embodiment is illustrated.

[0120] Figure 77 Another method of performing sensor wire capture in a seal carrier according to another embodiment is illustrated.

[0121] Figure 78 Illustrated is a perspective view of one example of a seal configured in accordance with an embodiment.

[0122] Figure 79 Pictured Figure 78 Cross-sectional side view of the seal.

[0123] Figure 80 A perspective view of one example of a seal configured in accordance with an embodiment is illustrated.

[0124] Figure 81 Pictured Figure 80 A cross-sectional perspective view of a seal.

[0125] Figure 82 Illustrated is a perspective view of one example of a seal configured in accordance with an embodiment.

[0126] Figure 83 Pictured Figure 82 Cross-sectional side view of the seal.

[0127] Figure 84 One method of triggering a device for performing automatic insertion according to an embodiment is illustrated.

[0128] Figure 85 The illustration shows a transmitter within a housing configured in accordance with an embodiment.

[0129] Figure 86 The diagram shows the second configuration Figure 33 Perspective view of the applicator system.

[0130] Figure 87 Illustrated is a perspective view of an applicator system configured in accordance with another embodiment.

[0131] Figure 88 The diagram shows the Figure 87 The line 88-88 is intercepted Figure 87 A cross-sectional perspective view of an applicator system.

[0132] Figure 89 Illustrated is a top perspective view of an assembled applicator system configured in accordance with some embodiments.

[0133] Figure 90 Pictured Figure 89 Bottom perspective view of the applicator system.

[0134] Figure 91 Illustrated is a bottom perspective view of a disposable housing on an adhesive patch with a removable liner, according to an embodiment.

[0135] Figure 92 Illustrated is a bottom perspective view of a disposable housing on an adhesive patch with a removable liner according to another embodiment.

[0136] Figure 93 Illustrated is a perspective view of an applicator system according to another embodiment and shown in a first configuration.

[0137] Figure 94 The diagram shows the second configuration Figure 93 Perspective view of the applicator system.

[0138] Figure 95 The diagram shows the Figure 93 Perspective view of the applicator system.

[0139] Figure 96 The diagram shows a first configuration Figure 93 A partial perspective view of an applicator system with certain components removed for illustration purposes.

[0140] Figure 97Illustrated is a partial perspective view of an applicator system having protective tabs configured in accordance with yet another embodiment.

[0141] Figure 98 Another example of a protective tab according to yet another embodiment is illustrated.

[0142] Figure 99 Illustrated is a top plan view of a needle configured in accordance with an embodiment.

[0143] Figure 100 Pictured Figure 99 Side view of the needle.

[0144] Figure 101 Illustrated is a perspective view of a multi-lumen needle configured in accordance with an embodiment.

[0145] Figure 102 Illustrated is a bottom perspective view of a transmitter configured in accordance with an embodiment.

[0146] Figure 103 Illustrated is a bottom perspective view of a transmitter configured in accordance with another embodiment.

[0147] Figure 104 The diagram shows a method for Figure 102 The line 104-104 is intercepted Figure 102 A cross-sectional top plan view of a transmitter, wherein the transmitter is shown mounted in a disposable housing.

[0148] Figure 105 Illustrated is an exploded perspective view of a lower housing and a disposable housing of an applicator system configured in accordance with another embodiment.

[0149] Figure 106 FIG. 1 shows a device having a transmitter installed therein according to another embodiment. Figure 105 A top perspective view of a disposable housing.

[0150] Figure 107 An elevational view of a needle showing one embodiment;

[0151] Figure 108 Shown Figure 107 A plan view of the bevel surface of the needle;

[0152] Figure 109 an elevational view showing the tubing bending to form the needle on the other hand;

[0153] Figure 110 shows a primary slope formed thereon Figure 109 Elevation drawing of the pipeline;

[0154] Figure 111 shows a secondary slope formed thereon Figure 110 Elevation drawing of the pipeline;

[0155] Figure 112 Pictured Figure 111 An enlarged perspective view of the inclined plane;

[0156] Figure 113 Shown Figure 111 a front elevation (along the central axis) of the distal end of the inclined plane;

[0157] Figure 114 is a perspective view of another embodiment of a needle, wherein the needle has a slot;

[0158] Figure 115 yes Figure 114 Cross-sectional view of the needle;

[0159] Figure 116 is a perspective view of another needle having a slot extending through the distal end of the needle;

[0160] Figure 117 yes Figure 116 A cross-sectional side view of a needle;

[0161] Figure 118 shows a schematic diagram of a needle configured according to another embodiment;

[0162] Figure 119 shows a schematic diagram of a needle configured according to another embodiment;

[0163] Figure 120 shows a schematic diagram of a needle configured according to another embodiment;

[0164] Figure 121 shows a schematic diagram of a needle configured according to another embodiment;

[0165] Figure 122 shows a schematic diagram of a needle configured according to another embodiment;

[0166] Figure 123 shows a schematic diagram of a needle configured according to another embodiment;

[0167] Figure 124 shows a schematic diagram of a needle configured according to another embodiment;

[0168] Figure 125 shows a schematic diagram of a needle configured according to another embodiment;

[0169] Figure 126 shows a schematic diagram of a needle configured according to another embodiment;

[0170] Figure 127 A schematic diagram of a conventional needle is shown;

[0171] Figure 128 Another needle configured in accordance with an embodiment is shown;

[0172] Figure 129 Another needle configured in accordance with an embodiment is shown;

[0173] Figure 130 shows a side view of a single-bevel needle configured in accordance with an embodiment;

[0174] Figure 131 Shown Figure 130 Top view of the needle;

[0175] Figure 132 shows a side view of another embodiment of a single bevel needle having a 13 degree bend angle;

[0176] Figure 133 shows a side view of another embodiment of a single-bevel needle having a 17-degree bend angle;

[0177] Figure 134 A side view of another embodiment of a kinked needle including a proximal slot to receive a sensor is shown. DETAILED DESCRIPTION

[0178] The following description and examples describe some example embodiments of the disclosed invention in detail. Those skilled in the art will recognize that the present invention has many variations and modifications encompassed by its scope. Therefore, the description of an example embodiment should not be considered to limit the scope of the present invention.

[0179] Sensor systems and applicators

[0180] Figure 1 1 is a schematic diagram of a continuous analyte sensor system 100 attached to a subject and in communication with a number of other exemplary devices 110 to 113. A transcutaneous analyte sensor system comprising an on-skin sensor assembly 600 is shown, which is fastened to the subject's skin via a disposable housing (not shown). The system includes a transcutaneous analyte sensor 200 and an electronics unit 500 (interchangeably referred to as "sensor electronics" or "transmitter") for wirelessly transmitting analyte information to a receiver. During use, the sensing portion of the sensor 200 is beneath the subject's skin, and the contact portion of the sensor 200 is electrically connected to the electronics unit 500. The electronics unit 500 is engaged with the housing, which is attached to an adhesive patch fastened to the subject's skin.

[0181] The on-skin sensor assembly 600 can be attached to the subject using an applicator adapted to provide easy and secure application. This applicator can also be used to insert the sensor 200 through the subject's skin. Once the sensor 200 has been inserted, the applicator is removed from the sensor assembly.

[0182] In general, the continuous analyte sensor system 100 includes any sensor configuration that provides an output signal indicating analyte concentration. The output signal comprising (e.g., sensor data, such as raw data stream, filtered data, smoothed data, and / or otherwise transformed sensor data) is sent to a receiver, which may be, for example, a smart phone, a smart watch, a dedicated device, and the like. In one embodiment, the analyte sensor system 100 includes a transcutaneous glucose sensor, such as described in U.S. Patent Publication No. US-2011-0027127-A1, the contents of which are hereby incorporated by reference in their entirety. In certain embodiments, the sensor system 100 includes a continuous glucose sensor and includes, for example, a transcutaneous sensor described in U.S. Patent No. 6,565,509 of Say et al. In another embodiment, the sensor system 100 includes a continuous glucose sensor and includes, for example, a subcutaneous sensor described with reference to U.S. Patent No. 6,579,690 of Bonnecaze et al. or U.S. Patent No. 6,484,046 of Say et al. In another embodiment, the sensor system 100 comprises a continuous glucose sensor and includes a subcutaneous sensor, such as described in U.S. Patent No. 6,512,939 to Colvin et al. In another embodiment, the sensor system 100 comprises a continuous glucose sensor and includes an intravascular sensor, such as described in U.S. Patent No. 6,477,395 to Schulman et al. In another embodiment, the sensor system 100 comprises a continuous glucose sensor and includes an intravascular sensor, such as described in U.S. Patent No. 6,424,847 to Mastrototaro et al. Other signal processing techniques and glucose monitoring system embodiments suitable for use with the embodiments described herein are described in U.S. Patent Publication No. US-2005-0203360-A1 and U.S. Patent Publication No. US-2009-0192745-A1, the contents of which are hereby incorporated by reference in their entireties. The sensor extends through a housing that maintains the sensor on the skin and provides electrical connections from the sensor to the sensor electronics, which are provided in the electronics unit.

[0183] In still further embodiments, the system 100 can be configured to apply a drug delivery device, such as an infusion device, to the patient's skin. In these embodiments, instead of or in addition to the sensor, the system can include a catheter connected to an infusion pump configured to deliver liquid medication or other fluids to the patient's body. In embodiments, the catheter can be deployed into the skin in much the same manner as the sensor, for example, as described herein.

[0184] In one embodiment, the sensor is formed of a wire or is in the form of a wire. For example, the sensor may include an elongated conductive body, such as a bare elongated conductive core (e.g., a metal wire) or an elongated conductive core coated with one, two, three, four, five or more layers of material, each of which may or may not be conductive. The elongated sensor can be long and thin, yet flexible and strong. For example, in some embodiments, the minimum dimension of the elongated conductive body is less than about 0.1 inches, less than about 0.075 inches, less than about 0.05 inches, less than about 0.025 inches, less than about 0.01 inches, less than about 0.004 inches, or less than about 0.002 inches. The sensor can have a circular cross-section. In some embodiments, the cross-section of the elongated conductive body can be oval, rectangular, triangular, polyhedral, star-shaped, C-shaped, T-shaped, X-shaped, Y-shaped, irregular, or the like. In one embodiment, a conductive wire electrode is used as the core. One or two additional conductive layers can be added (e.g., with an intervening insulating layer provided for electrical isolation) to this coated electrode. The conductive layer can include any suitable material. In certain embodiments, it may be desirable to employ a conductive layer that includes conductive particles (ie, particles of conductive material) in a polymer or other binder.

[0185] In certain embodiments, the material used to form the elongated conductive body (e.g., stainless steel, titanium, tantalum, platinum, platinum-iridium, iridium, certain polymers, and / or the like) can be strong and rigid, and therefore resistant to fracture. For example, in some embodiments, the ultimate tensile strength of the elongated conductive body is from about 80 kPsi to about 500 kPsi. In another example, in some embodiments, the Young's modulus of the elongated conductive body is from about 160 GPa to about 220 GPa. In yet another example, in some embodiments, the yield strength of the elongated conductive body is from about 60 kPsi to about 2200 kPsi. In some embodiments, the small diameter of the sensor provides (e.g., imparts, enables) flexibility to these materials and, therefore, to the sensor as a whole. Thus, the sensor can withstand repeated forces applied thereto by surrounding tissue.

[0186] In addition to providing structural support, elasticity, and flexibility, in some embodiments, the core (or its components) also provides for electrical conduction of electrical signals from the working electrode to the sensor electronics (not shown). In some embodiments, the core comprises a conductive material, such as stainless steel, titanium, tantalum, a conductive polymer, and / or the like. However, in other embodiments, the core is formed of a non-conductive material, such as a non-conductive polymer. In yet other embodiments, the core comprises multiple material layers. For example, in one embodiment, the core comprises an inner core and an outer core. In yet another embodiment, the inner core is formed of a first conductive material, and the outer core is formed of a second conductive material. For example, in some embodiments, the first conductive material is stainless steel, titanium, tantalum, a conductive polymer, an alloy, and / or the like, and the second conductive material is a conductive material selected to provide electrical conduction between the core and the first layer and / or to attach the first layer to the core (for example, if the first layer is formed of a material that does not attach well to the core material). In another embodiment, the core is formed of a non-conductive material (for example, a non-conductive metal and / or a non-conductive polymer), and the first layer is a conductive material, such as stainless steel, titanium, tantalum, a conductive polymer, and / or the like. The core and first layer may be of a single (or the same) material, such as platinum. Those skilled in the art will appreciate that additional configurations are possible.

[0187] In the illustrated embodiment, the electronics unit 500 can be attached to the sensor 200 in a releasable manner. The electronics unit 500 includes an electronic circuit associated with measuring and processing continuous analyte sensor data, and is configured to perform an algorithm associated with the processing and calibration of sensor data. For example, the electronics unit 500 can provide various aspects of the functionality of the sensor electronics module, as described in U.S. Patent Publication No. 2009-0240120-A1 and U.S. Patent Publication No. 2012-0078071-A1, the contents of which are hereby incorporated by reference in their entirety. The electronics unit 500 can include hardware, firmware and / or software that realizes the measurement of the level of analyte via a glucose sensor (e.g., analyte sensor 200). For example, the electronics unit 500 may include a potentiostat, a power source for providing power to the sensor 200, other components for signal processing and data storage, and preferably a telemetry module for one-way or two-way data communication between the electronics unit 500 and one or more receivers, repeaters and / or display devices (e.g., devices 110 to 113). The electronics may be attached to a printed circuit board (PCB) or the like, and may take various forms. For example, the electronics may take the form of an integrated circuit (IC), such as an application specific integrated circuit (ASIC), a microcontroller and / or a processor. The electronics unit 500 may include a sensor electronics configured to process sensor information, such as stored data, analyzed data streams, calibrated analyte sensor data, estimated analyte values, compared estimated analyte values ​​and time corresponding measured analyte values, analyzed estimated analyte value changes, and similar processing. Examples of systems and methods for processing sensor analyte data are described herein and in U.S. Patent Nos. 7,310,544, 6,931,327, 2005-0043598-A1, 2007-0032706-A1, 2007-0016381-A1, 2008-0033254-A1, 2005-0203 No. 2005-0192557-A1, U.S. Patent Publication No. 2006-0222566-A1, U.S. Patent Publication No. 2007-0203966-A1, and U.S. Patent Publication No. 2007-0208245-A1, the contents of each of which are hereby incorporated by reference in their entirety.

[0188] One or more transponders, receivers, and / or display devices, such as a key fob transponder 110, a medical device receiver 111 (e.g., an insulin delivery device and / or a dedicated glucose sensor receiver), a smartphone 112, a portable computer 113, and the like, are operatively linked to the electronics unit, which receives data from the electronics unit 500, also referred to herein as a transmitter and / or sensor electronics body, and in some embodiments transmits data to the electronics unit 500. For example, sensor data can be transmitted from the sensor electronics unit 500 to one or more of the key fob transponder 110, the medical device receiver 111, the smartphone 112, the portable computer 113, and the like. In one embodiment, the display device includes an input module having a quartz crystal operatively connected to an RF transceiver (not shown), which together function to transmit, receive, and synchronize a data stream from the electronics unit 500. However, the input module can be configured in any manner capable of receiving data from the electronics unit 500. Upon receipt, the input module sends the data stream to a processor, which processes the data stream, such as described in more detail below. The processor is a central control unit that performs processing, such as storing data, analyzing data streams, calibrating analyte sensor data, estimating analyte values, comparing the measured analyte values ​​of estimated values ​​and time corresponding analyte values, analyzing the change in estimated analyte values, downloading data, and controlling a user interface by providing analyte values, prompts, messages, warnings, alarms, and the like. The processor includes the hardware for performing the processing described herein, such as a read-only memory (ROM) providing permanent or semi-permanent storage of data, storing data such as sensor ID (sensor identity), receiver ID (receiver identity), and programming (e.g., for performing estimation and programming of other algorithms described elsewhere herein) for processing data streams, and a random access memory (RAM) storage system cache memory and contributing to data processing. The output module that can be integrally and / or operatively connected to the processor includes programming (and any processing caused in the processor) for generating output based on the sensor data received from the electronics unit.

[0189] In some embodiments, the analyte value is displayed on a display device. In some embodiments, prompts or messages may be displayed on the display device to convey information to the user, such as reference outliers, requests for reference analyte values, therapy recommendations, deviations of measured analyte values ​​from estimated analyte values, or the like. Additionally, prompts may be displayed to guide the user through calibration or calibration troubleshooting.

[0190] In addition, the data output from the output module can provide wired or wireless, one-way or two-way communication between the receiver and the external device. The external device can be any device that interfaces with or communicates with the receiver. In certain embodiments, the external device is a computer, and the receiver can download current or historical data for, for example, a physician's retrospective analysis. In certain embodiments, the external device is a modem, and the receiver can send a warning, a warning, an emergency message or the like to the other party, such as a doctor or a family member, via a telecommunications line. In certain embodiments, the external device is an insulin pen, and the receiver can recommend, for example, an amount of insulin and time to be communicated to the insulin pen. In certain embodiments, the external device is an insulin pump, and the receiver can recommend, for example, an amount of insulin and time to be communicated to the insulin pump. The external device can include other technologies or medical devices, such as a pacemaker, an implanted analyte sensor patch, other infusion devices, telemetry devices or the like. The receiver can communicate with the external device and / or any number of additional devices via any suitable communication protocol, including any of radio frequency, Bluetooth, universal serial bus, wireless local area network (WLAN) communication standards, including IEEE802.11, 802.15, 802.20, 802.22 and other 802 communication protocols, ZigBee, wireless (e.g., cellular) telecommunications, paging network communications, magnetic induction, satellite data communications, GPRS, ANT, and / or proprietary communication protocols.

[0191] Certain aspects of the applicator system are described in US Patent Publication No. 2013-0267811-A1 and US Patent No. 7,497,827; both of which are owned by the assignee of the present application and are incorporated herein by reference in their entirety.

[0192] In particular, the embodiments described in the applications incorporated by reference above depict systems and methods in which a transcutaneous sensor is applied to a patient and the sensor wire is positioned within a housing to which a transmitter is attached. In some cases, a torsion spring provides the force required for the system to perform the steps, and energy is similarly stored in the torsion spring, which is preloaded before shipping. However, in other embodiments, it may be necessary to increase the force provided by the torsion spring, or to completely replace the torsion spring with another source of force. One reason for this is that, in the above embodiments, the torsion spring is shipped and stored in a preloaded or constrained configuration and is therefore subject to loss of spring force over time. In addition, the use of a previously constrained torsion spring (or any similar single spring) results in a reduced spring force at the end of the spring's movement due to Hooke's law F = -kx, where x is the distance from the equilibrium position. That is, at the end of the spring's movement, x is close to zero, and so is the force.

[0193] The embodiments described below generally discuss sensors composed of one or more sensor lines. However, it will be understood that the sensors are not limited to these line shapes or linear arrangements. Rather, the sensors can be implemented as planar sensors, volumetric sensors, point sensors, or in other shapes, as will be understood given this description.

[0194] For example, see Figure 2 , line 12 represents the spring force given by Hooke's law described above, and curve 14 represents the force required during the execution of the above-described insertion step. In the event that the required force exceeds the force available from the spring, for example, in section 16, the system cannot provide the necessary force. A larger spring force can be provided by a larger or stiffer spring, for example, see line 12', but this is associated with other problems, such as tissue damage when such a large force is used to advance the needle into the body, and is also difficult to implement in a small housing, as desired.

[0195] Therefore, various other types of applicators can be used and are described below. These applicators strive to tailor the applied force so that the stored force is available and applied as needed. Specific examples will be given below with respect to specific applicators. Generally, it will be desirable to have more force available than is required for any given force profile. It should also be noted that a typical force profile has a bimodal distribution, for example, having at least two maxima, such as Figure 2 A bimodal distribution can be seen in FIG. The first maximum, e.g., the first portion of the force distribution, is caused by the force required to force the needle into the subject's skin. Once the skin has been penetrated, the force decreases because the interstitial tissue is easier to penetrate. This force is therefore in the direction of needle propagation, e.g., the direction of insertion. The next maximum, e.g., the second portion of the force distribution, is caused by retraction, and specifically retraction of the needle and / or cannula, which is a force in the opposite direction of insertion. Thus, while two positive maxima are shown in the figure for convenience, i.e., each indicated by a positive force value, it will be understood that these maxima relate to forces acting in opposite directions.

[0196] In one embodiment, Figure 3 As shown in , a torsion spring is used for the insertion step, i.e., the first part of the force distribution, and another drive mechanism, which may be different from the torsion spring, is used for the retraction step, i.e., the second part of the force distribution. In the insertion step, the needle and sensor are inserted into the body; in the retraction step, the needle and cannula are removed, as will be described. Figure 3 In the invention, the drive mechanism is a coil spring, also called a "booster" spring, which is preloaded so as to be stored in a compressed state. The preload provides the energy necessary for the spring to expand and thus cause the retraction of the needle and cannula.

[0197] Figure 3 The force distribution of the device is given by Figure 4 curve Figure 22 As shown in the curve Figure 22 In, with Figure 2 The same bimodal force profile 14 is still visible in FIG, with the first hump corresponding to needle insertion having the majority of the force required for skin penetration, and the second hump corresponding to cannula and needle retraction. However, in this case, at or near the beginning of the retraction step, the assist spring is activated, resulting in the rise in force shown from line 12″ to line 18, which then exceeds the force required for cannula and needle retraction. Since the assist force is provided by the spring, the force profile of the spring (line 18) follows the form F = -kx. In some cases, the force included in Figure 3 In the exemplary device shown in , the force from the torsion spring can be stopped, and the retraction force is provided by the booster spring completely. In other embodiments, the torsion spring and the booster spring can both participate in providing the retraction force.

[0198] The following will describe in detail Figure 3 applicator, but initially it should be noted that it consists of many interoperating components and that these Figure 5 In particular, the applicator housing is generally described, but with particular reference to Figure 3 and 6 Most of the operations performed by the applicator involve the seal carrier 26 and its components. Operations generally involve sensor wire insertion performed by the sensor insertion drive mechanism, which is Figures 7 to 16 is described in, where in e.g. Figure 20 to 3 8. The drive mechanism typically (but not always) comprises a main drive component, such as a torsion spring, and a booster component, such as a booster spring. Although components often perform multiple functions, they can be most generally divided into insertion components and retraction components, where the insertion component is the primary component of the retraction mechanism. Figure 3 、 6 and 7 to 11. Exemplary elements for insertion are described in Figure 5 Generally speaking, the retracted components are listed in Figures 13 to 16 , and exemplary elements thereof are also shown in Figure 5 However, the above is intended to be a general and non-limiting description. For example, in one embodiment, the needle and cannula constitute the insertion components that play a key role in the insertion of the sensor, but they are also the key components that will be retracted once the sensor is inserted.

[0199] Now see in more detail Figure 3, the device 20 includes an upper or top applicator housing 30 and a lower or bottom applicator housing 40. The upper applicator housing 30 and the lower applicator housing 40 each form part of a disposable device, including all components shown in and between the upper and lower housings. In use, the upper housing is mounted to the lower housing and they are shipped as a single unit, with a torsion spring and a booster spring (both in a preloaded state). Other types of drive mechanisms are also described below, which can be preloaded or not. The term "preloaded" or "preloaded" here refers to a drive mechanism that performs the required drive step when activated. For example, a spring that is not in a state of equilibrium can be compressed or expanded, and each state can be referred to as "preloaded". The torsion spring can be wound so that when released, a torque about the axis is provided on the element. This winding is considered a form of preload here.

[0200] The apparatus 20 is intended to perform the steps of inserting a sensor (typically embodied by a sensor wire) into a patient in vivo, with the sensor wire extending out of the patient and coupled to an extracorporeal disposable housing that is attached to the patient's skin. Figure 3 The transmitter has electrical contacts that, when snapped onto the disposable housing, make contact with corresponding conductive bumps through which the sensor wires pass. The sensor wires have corresponding windows in their insulation, so each sensor wire is electrically coupled to a different bump.

[0201] The seal carrier 26 is Figure 3 , with seal 24 located on seal carrier 26. Seal 24 performs various functions, including protecting the sensor wires from moisture, providing a reliable electrical connection, allowing accurate sensor placement during insertion and retraction steps, and retaining the sensor wires, i.e., providing a secure connection to the sensor wires to prevent the disposable housing from being removed while the sensor wires remain within the body.

[0202] Two holes 34a and 34b are defined in the seal 24, and the conductive blocks are located in the holes ( Figure 3 (not shown). The seal carrier 26, the seal 24 and the disposable housing 36 are Figure 3 The seal carrier 26 and seal 24 rotate about hinge 28, which also serves to couple the seal carrier 26 to a disposable housing 36 that is removably mounted to the lower surface of the lower housing 40. Details of the disposable housing 36 and seal carrier 26 are provided in FIG. Figure 39 As can be seen in the figure, it shows that Figure 34. The seal 24 and seal carrier 26 are positioned in the same position in the disposable housing 36, i.e., at an angle of approximately 45° to the bottom surface of the lower housing 40. The disposable housing 36, seal carrier 26, and seal 24 are maintained in this position by many features described below. However, once the sensor line has been installed in the patient and the cannula 78 and cannula hub 32 have been retracted, the seal carrier 26 and seal 24 can be rotated about the hinge 28 and placed in the disposable housing 36 (e.g., generally parallel to the plane of the disposable housing 36 or in said plane). In some embodiments, the seal carrier 26 can be manually rotated downward by the user. Alternatively, in some embodiments, a spring 38 (described in more detail below) or other biasing member can be used to cause the seal carrier 26 and seal 24 to transition from an angled position with the base of the lower housing 40 to a rest position in the disposable housing (e.g., parallel to the plane of the disposable housing or in said plane) at the same time as the disposable housing is released from the applicator housing, or before or after the disposable housing is released from the applicator housing.

[0203] See now Figure 6 Together Figure 3 , an exemplary drive assembly is described with respect to the depicted components. It will be understood that variations of these components and steps are encompassed within the scope of the present description.

[0204] The user can position the applicator 20 at the desired location on their skin and can remove the protective tab 42, allowing access to the button 44. Depression of the button 44 then begins the insertion process.

[0205] Specifically, depression of the button 44 disengages the trigger tab 46 from the corresponding stop 49 on the torsion spring housing 52. Figure 15 , the trigger tab 46 becomes disengaged by translation of the button link 56 when the button 44 is depressed. The button 44 and / or button link 56 may be biased upward so that after the trigger tab 46 is disengaged from the stop 49 and the applicator 20 is activated, the button 44 is urged back to its original position.

[0206] In an embodiment, the protective tab 42 can serve as a safety mechanism or lock, thereby preventing the button 44 from being pressed (and therefore the system from being activated) until the protective tab 42 is separated and / or removed from the upper applicator housing 30. In an embodiment, the protective tab can include one or more components that extend above the surface of the upper applicator housing 30 beyond the perimeter of the button 44 to prevent the button 44 from being pressed until the protective tab (or at least the portion extending beyond the perimeter of the button 44) is removed. In an embodiment, the protective tab can be coupled to the upper applicator housing 30 by one or more brittle elements that are configured to break when the tab is pressed upward, downward, sideways, or when the protective tab is twisted or pulled. The brittle element can be configured to break after the application of a force between about 1.0 and 1.8 pounds. In some embodiments, the brittle element can be configured to break after the application of a force between about 1.3 and 1.5 pounds. Depending on the desired user interaction, the protective tab can be configured to be removed via a twisting motion, a sweeping motion, a bending motion, or a pulling motion. Figure 6 As shown in FIG, the protective tab 42 can extend straight upward from the upper applicator housing 30, such as along the mid-plane of the system (eg, in a plane perpendicular to the plane of the disposable housing 36).

[0207] In some embodiments, the protective tab and / or button may include one or more visual or tactile features configured to indicate to the user the proper removal method. For example, the protective tab may include arrows, protrusions, ridges, and / or tacky grips to indicate where and in what direction the user should press (or pull or twist) on the tab to break the frangible member. Figure 97 An applicator system 20a configured in accordance with one such embodiment is illustrated in which the protective tab 42a has ridges 43a, 43b disposed on one side thereof to indicate to the user that the tab 42a should be bent to the left in order to break the protective tab 42a off the upper applicator housing 30. In another example, the protective tab may extend from the applicator housing at an angle, such as upward, downward, or tilted to the left or right, to indicate the direction in which the user should press (or pull or twist) on the tab to break the frangible member. Figure 98 Protective tab 42b is illustrated configured in accordance with one such embodiment, wherein protective tab 42a bends to the right as it extends away from the housing to indicate to the user that tab 42a should be bent to the right in order to break protective tab 42b away from the housing.

[0208] Reference again Figure 6Once the trigger tab 46 disengages from the torsion spring housing stop 49, the torsion spring housing 52 is free to rotate under the force provided by the preloaded torsion spring 54. Because the torsion spring housing 52 has a pin 58 that engages with and moves within the yoke 62 of the scotch yoke mechanism, the rotational movement of the torsion spring housing 52 is converted into longitudinal movement of the various components in the applicator. The yoke 62 of the scotch yoke mechanism is integral with the outer needle hub 66, and the two are referred to herein as the yoke / needle hub assembly 64. The inner needle hub 68 moves within the outer needle hub 66, and the two are Figure 7 Shown in an expanded configuration, Figure 7 Also shown are a needle 72 and a booster spring 74. A sensor wire is deployed through a lumen 76 in the needle 72.

[0209] Figure 8 and 9 The assembly 64 is illustrated relative to the internal needle hub 68 and the cannula hub 32 in which the cannula 78 is mounted. The needle 72 passes through the cannula 78 during sensor deployment. The cannula 78 passes through the seal carrier 26, the seal 24, and the knob 82 to provide passage for the needle 72 during sensor insertion. As part of the insertion sequence, the cannula 78 is removed from the seal carrier, the seal, and the knob, and in particular, is removed by the force of the assist spring 74. Figure 10 Illustrated are side views of the various components described.

[0210] The sensor wire may have a kink that is defined to allow for a friction fit within the needle. In this way, the sensor wire is retained within the needle while still being able to translate through the needle by the force of the push rod. Generally, the kink may be configured to retain the wire within the needle, but in situations where the wire is external to the needle, and within a cannula, the kink will not retain the sensor wire within the cannula, or will only be able to minimally retain the sensor wire.

[0211] Figure 11 and 12 The pusher hub 84 is shown with the pusher 86 located therein. The pusher hub 84 is located below the yoke 62 and its arms 88a and 88b extend around the assembly 64 and, in particular, around the outer needle hub 66. During the insertion phase, the pusher hub 84 travels in the distal direction with the yoke / needle hub assembly 64 because the pusher hub has tabs 124a and 124b at the distal ends of its arms 88a and 88b (see FIG. Figure 11 ), which engage slots 126a and 126b on the yoke / needle hub assembly 64 (see Figure 7 ).

[0212] Pushrod 86 is inserted into the needle proximal to the sensor and, after insertion, holds the sensor in place (e.g., in position) while the needle and cannula are retracted. Pushrod 86 can hold the sensor in place, for example, in vivo, because it is rendered stationary at the distal end of its travel, i.e., the pushrod remains in place (e.g., remains fixed or in the same position) while the needle and cannula are moved proximally around it. Pushrod hub 84 is described in more detail below.

[0213] In use, the force of the torsion spring causes the yoke / needle hub assembly 64, including the outer needle hub 66, to move downward, i.e., distally, toward the seal carrier 26. The inner needle hub moves along with the outer needle hub in this downward stroke due to the engagement of the tabs 91a and 93a with the slots 94a (and the corresponding tabs with the corresponding slots on the opposite side of the assembly 64). By engaging the tabs 91a and 93a of the inner needle hub 68 with the locking features of the slots 94a in the outer needle hub 66 (and the corresponding tabs with the corresponding slots on the opposite side of the assembly 64) during assembly of the components, the spring 74 becomes compressed and thus preloaded during assembly. When the inner needle hub is caused to disengage from the outer needle hub, as will be described, the force of the expanding spring 74 causes the inner needle hub to move in the proximal direction away from the outer needle hub.

[0214] See Figure 13 , the cannula hub 32, which is initially stationary relative to the applicator, has two arms 96a and 96b, with the proximal end 98 defining two detents. The distal end 102 of the inner needle hub 68 is shown engaged in the first detent, which may be the initial position of the assembly prior to button activation. As the inner needle hub 68 and the cannula hub 32 move toward each other, and more particularly, as the inner needle hub 68 moves toward the cannula hub 32, the distal end 102 of the inner needle hub 68 disengages from the first detent and moves into the second detent 104, which occurs as the torsion spring and scotch yoke mechanism urge the assembly 64 downward toward the cannula hub 32.

[0215] At or near the lowest point of travel of the scotch yoke mechanism, the two tabs 106 ( Figure 11 Only one is shown) moves past the corresponding stop 108 ( Figure 6 The push rod hub is configured to move in a proximal direction (only one of which is shown), causing the tabs to initially compress toward the center of the push rod hub and then expand as the tabs distally pass the stop, thereby limiting proximal travel of the push rod hub. In other words, the push rod and push rod hub are prevented from traveling in the proximal direction because the remainder of the assembly is traveling in the proximal direction when the scotch yoke mechanism begins its proximal return path (e.g., the retraction phase).

[0216] In some embodiments, the push rod return spring element 118 ( Figure 11) is positioned at the distal end of the arm of the push rod hub. With the push rod hub 84 in the distal position, the push rod return spring element 118 abuts against the bottom applicator housing 40 ( Figure 6 ) is biased against a stop 114 on the push rod hub so that the push rod hub is substantially prevented from all movement, including vibration. Specifically, it should be noted that in order to move the push rod hub into the distal position and lock it in place (e.g., secure it in the distal position), the tab 106 (forming a hook that can be deflected) passes a stop 108 (also known as a catch) on the bottom applicator housing 40. The hook deflects inward (e.g., toward the push rod) when it passes the catch during the downward or distal travel of deployment. In order to ensure that the hook 106 is secured in the catch 108 for the retraction phase of deployment, a minimum amount of overtravel is required. This overtravel leads to ambiguity in the position of the push rod. Since placement accuracy is defined by the push rod, this ambiguity can be detrimental. A deflecting component is employed, such as a push rod return spring element 118, which compresses during the downward travel of the push rod hub at the distal end. When deployment is reversed, the push rod return spring provides a retaining force bias for the push rod against the catch. This removes ambiguity in the pushrod position, as well as deleterious effects such as vibration.Since the pushrod hub and pushrod are now fixed at the farthest end of their travel, the sensor is placed in its deepest and final position in the body.

[0217] The torsion spring continues to rotate the wheel, causing the yoke to begin moving in the proximal direction while the push rod hub remains stationary. The proximal movement of the yoke combined with the blocked push rod hub activates the assist spring to retract the needle and cannula as follows. In one embodiment, the amount of rotation remaining in the torsion spring after the pin 58 reaches its lowest point is 5% to 20%, for example 10%, of its total rotation.

[0218] First, see Figure 14 The pusher hub 84 is forced outwardly by the tabs 124a and 124b to disengage from the yoke / needle hub assembly 64 by the action of ramps on the surface of the yoke / needle hub assembly 64 and / or the tabs 124a and 124b themselves, or both. As the needle is pulled out of the body, the sensor is placed into the body because the pusher is now fixed in the distal position and backstops or holds the sensor in place (e.g., resists proximal movement of the sensor).

[0219] Next, two ramps 116 (see Figure 11 , of which only one ramp is visible) is provided on the inner surface of the pusher hub 84. Since the pusher hub 84 is stationary once it has reached its lowest (furthest) point of travel, but the outer needle hub (yoke / needle hub assembly 64) is not, as the yoke / needle hub assembly 64 begins to move proximally in the retraction phase, the ramp 116 deflects the release tab 92a (and the corresponding tab on the opposite side of the assembly 64; see Figure 13), thereby deflecting the release tab 92a and locking tabs 91a, 93a inwardly toward the needle and disengaging the locking tabs 91a and 93a from the slots 94a (and serving the same function on the opposite side of the assembly 64). This action releases the spring and forces the inner needle hub upward in the proximal direction by the force of a booster spring, which is attached at one end to the inner needle hub and at the other end to the stationary outer needle hub. Figure 13 As shown in FIG, the inner needle hub 68 is coupled to the cannula hub 32, but at this point, the distal end 102 is within the second catch 104. However, the distal end 102 cannot be disengaged from the cannula hub 32, and therefore the cannula hub and the needle are retracted simultaneously. Because the distal end 102 is within the second catch 104, i.e., because two catches are provided, the needle can be configured to protrude from the cannula by, for example, 0 to 150 mils, such as 100 mils, or even negative. The benefits of these systems ensue, as will be described below with respect to the seal and seal slingshot. In some cases, the needle does not need to protrude from the cannula during the retraction phase.

[0220] As described above, at this point, the anti-scotch yoke mechanism now begins to drive in the proximal direction. However, when the initial preload of the torsion spring causes distal movement of the yoke, in some cases, the force of the assist spring can be used to reload or "backdrive" the torsion spring. Therefore, in these embodiments, a ratchet mechanism can be used to prevent movement of the torsion spring. In particular, and referring to Figure 15 , the torsion spring housing 52 is shown in an initial configuration wherein the rotation of the housing is locked by the trigger tab 46 and the torsion spring (not shown) is in its fully loaded state. The torsion spring housing 52 has a ratchet pawl 48 which is prevented from rotating by the trigger tab 46 (e.g. Figure 15 Once the trigger tab 46 moves out of the way of the torsion spring housing stop 49 (e.g., by depression of the button 44), the torsion spring housing 52 becomes free to rotate (e.g., Figure 15 In the figure (in the counterclockwise direction), until the ratchet pawl 48 engages in the ratchet teeth 136 and / or the torsion spring housing stop 49 hits the hard stop 47. Figure 15 In the configuration shown in FIG, the pin 58 for the scotch yoke is in its top dead center position, ie in its starting position.

[0221] Figure 16The configuration is shown when the assist force is pushing on the pin 58 in the direction of arrow 138. Since the direction of rotation caused by the torsion spring is counterclockwise, i.e., the assist force is pushing on the pin in a clockwise direction, there is a possibility of reverse driving of the torsion spring. The engagement of the ratchet pawl 48 within the ratchet teeth 136 can be used to inhibit or prevent this reverse driving. In one embodiment, the device is configured so that the assist force spring is triggered after the ratchet pawl 48 engages the ratchet teeth 136. In this way, any force on the pin 58 caused by the assist force will not result in reverse driving of the torsion spring. It should be noted that in Figure 16 In the position shown in , the needle has been almost removed from the body, but the cannula has not yet been retracted.

[0222] The engagement of the ratchet pawl 48 with the ratchet teeth 136 prohibits or prevents clockwise rotation or reverse drive of the torsion spring housing 52. Similarly, the engagement of the stop 49 against the hard stop 47 prohibits or prevents further counterclockwise rotation of the torsion spring housing 52. Therefore, the movement of the pin 58 is also blocked, thereby stopping the movement of the scotch yoke mechanism, including the outer needle hub. However, the needle continues to retract because it is driven by the booster spring on the inner needle hub. As described above, the movement of the inner needle hub further causes the retraction of the cannula hub. In this way, the cannula and needle are fully retracted by the booster spring through the seal. Since the cannula hub and cannula no longer support the seal carrier, it is free to rotate (by gravity) into the disposable housing. In many cases, it is desirable to include a push spring 38 to assist this movement, which is held up by the cannula hub 32 until it is removed and the seal carrier is ready to be lowered into the disposable housing 36, as described in more detail below. In some embodiments, one or more retention features 166 of the lower housing 40 can be used to prevent the disposable housing 36 from being released from the housing 40 until after the cannula has been retracted from the seal. In some embodiments, rotation of the seal carrier can facilitate release of the retention features 166, thereby allowing the disposable housing to be separated from the device 20. Once the inner needle hub is in the fully retracted position, the sensor has been placed in the body and the applicator can be removed, thereby leaving the disposable housing assembly.

[0223] Figures 3 to 16 Advantages of embodiments of the device may include one or more of the following: The device has high usability, smooth sinusoidal mechanism motion such as caused by the scotch yoke, and the ability to tune or control the resulting force.

[0224] Now refer to Figure 89 , illustrates a top perspective view of the assembled device 20 showing the upper applicator housing 30 coupled to the lower applicator housing 40 prior to deployment of the device 20 , with the protective tab 42 intact on the button 44 . Figure 90 A bottom perspective view of the assembled device 20 prior to deployment is shown. Figure 90As can be seen in FIG, the upper applicator housing 30 and the lower applicator housing 40 can be coupled together by mating short nails 31 and holes 41. Figures 89 to 91 In the embodiment illustrated in FIG, spike 31 extends from upper applicator housing 30 and aperture 41 forms part of lower applicator housing 40, but other configurations (e.g., the reverse configuration) are possible. In some embodiments, upper and lower applicator housings 30, 40 can be coupled together using an interference fit between spike 31 and aperture 41. In some embodiments, spike 31 and aperture 41 can be staked together, for example, thermoplastically or heat staked together.

[0225] Figure 90 Also illustrated is an adhesive patch 90 disposed on the lower (distal end or substrate) surface of the lower applicator housing 40. The adhesive patch 90 includes a removable liner 80 that covers and protects the adhesive of the adhesive patch 90 until it is removed by the user before deployment. In an embodiment, the adhesive may include a pressure-sensitive or pressure-activated adhesive. In an embodiment, the substrate of the lower housing 40 may include a rigid or semi-rigid surface that can be configured to promote the activation of the adhesive on the adhesive patch 90 at least in the area surrounding the disposable housing of the patch when the applicator device 20 is placed or pressed against the skin. In some embodiments, the lower portion or substrate surface of the lower housing 40 may be smooth (flat or slightly contoured) so as to provide uniform activation over the entire range of the adhesive at least in the area surrounding the disposable housing of the patch. In other embodiments, the lower portion or substrate surface of the lower housing 40 may include one or more dimples, protrusions, ridges or other embossed features to ensure activation of the adhesive in certain areas, such as near the outer edge of the patch 90 and / or in the area immediately surrounding the disposable housing. In some embodiments, the lower or base surface of the lower housing 40 can be sized and shaped to have a larger footprint than the adhesive patch 90 (e.g., such that the base surface of the lower housing 40 extends past the adhesive patch 90 in one or more directions in the plane of the disposable housing 40). This configuration can help prevent unwanted folding or wrinkling of the patch 90.

[0226] Now refer to Figure 91 , shows a bottom perspective view of one example of an adhesive patch 90a having a disposable housing 36 disposed thereon and having a removable liner 80a disposed on an opposing surface thereof. The removable liner 80a includes a first portion 81a having a release tab 83a that folds back from the patch 90a and a second portion 85a having a release tab 87a that also folds back from the patch 90a. The release tabs 83a, 87a are shown separated from one another for illustration purposes. The liner 80a includes an opening 89a through which the needle and sensor can pass during the insertion process. Figure 91In the embodiment illustrated in FIG, first portion 81a may extend across a substantially equal portion of the surface area of ​​patch 90a as second portion 85a such that first and second portions 81a, 85a meet at or near opening 89a in the center of adhesive patch 90a.

[0227] Now refer to Figure 92 , shows a bottom perspective view of another example of an adhesive patch 90b having a disposable housing 36 disposed thereon and having a removable liner 80b disposed on an opposing surface thereof. The removable liner 80b includes: a first portion 81b having a release tab ( Figure 92 and a second portion 85b having a release tab 87b also folded back from the patch 90b. The liner 80b includes an opening 89b through which the needle and sensor can pass during the insertion process. Figure 92 In the embodiment illustrated in FIG, first portion 81b may extend a greater portion of the surface area of ​​patch 90b than second portion 85b such that first and second portions 81b, 85b meet away from the center of adhesive patch 90b and away from opening 89b.

[0228] The sensor wire itself can have one or more contact areas separated by polyurethane layers, for example corresponding to an outer silver layer and an inner platinum layer. It will be understood that the specific composition of these conductive and insulator layers can vary depending on the embodiment. The conductive areas can be accessed directly (in the case of contact with the outer silver layer) or via removal of the silver and polyurethane layers to gain access to the platinum layer.

[0229] The wire may include a portion that is generally outside the body and a segment that is generally inside the body, both of which are about 1 / 2 inch in length. The outside-body portion may include electrical contacts, and the inside-body portion may include a sensing portion, which may be located at the distal tip of the inside-body portion or may be proximal to the distal tip of the inside-body portion. A transmitter may be employed that has electrical contacts (not shown) that contact the first and second pucks. Since the wire also contacts the pucks, the wire is in signal communication with the transmitter. To ensure that each puck contacts a separate portion of the wire, an insulating portion of the wire may be positioned between the pucks. In this way, a first contact (e.g., a silver portion) contacts the first puck, and a second contact (e.g., a platinum portion) contacts the second puck. In one embodiment, the diameter of the pucks is about 80 mils, and the distance between the pucks is about 215 mils.

[0230] Figures 17 to 19Another arrangement is shown in which a robust connection can be made from the sensor wire to the transmitter. Specifically, the seal carrier 26 is shown with spring connectors 133a and 133b. Each spring 133 includes a compression section 129 and an extension section 131. The springs 133 are typically metal, such as stainless steel, copper, etc., and may be electroplated with a coating such as gold, nickel, etc. In use within the seal carrier, the springs 133 replace the bumps 123 and 125 described above. Figure 17 In the arrangement shown in FIG, the top portion of the spring is a compression section 129 and is used to provide pressure against the transmitter contacts for a robust connection. The bottom section 131 is an extension spring and is therefore configured to pull the coils together in the relaxed state. The coils in the extension section are held apart by the cannula 78 during insertion (and partially during retraction). When the cannula is removed, the coils relax and contract onto the sensor wire 117, holding it in place with a strong friction connection, thereby connecting the sensor wire to the spring.

[0231] Figures 17 to 19 The embodiment has the advantage of reducing motion-induced noise in the signal in long duration sessions, eg, more than 10 days.

[0232] In an alternative embodiment of an applicator according to the principles of the present invention, a wearable device, such as embodied in a disposable housing 36 and a transmitter (described below), can be deployed in a subject using the systems and methods described in, and particularly as disclosed in, the applications incorporated by reference above. For example, in the applications incorporated by reference, the sensor wire is inserted into the subject through a cannula, and the wire is sealed with an elastomeric seal that is compressed by the insertion of the transmitter.

[0233] exist Figures 3 to 16 In the above embodiments, a supplemental source of stored energy (i.e., a separate assist spring) is disclosed to provide supplemental force to ensure that all steps of insertion and retraction can be effectively accomplished, i.e., the force applied during both the insertion and retraction steps is generally always greater than the desired force profile (see Figure 2 ). The primary force source spring 54 provides the energy source for the insertion force and even for a portion of the retraction force, particularly with respect to an insertion component such as a needle. The secondary force source spring 74 provides the energy source for the retraction force, particularly with respect to an insertion component such as a cannula. The additional retraction force is necessary in part because the insertion component (e.g., a cannula) is retracted by a source of resistance (e.g., an elastomeric seal). While a single large or larger spring could also be employed to achieve the same function, the use of these adversely increases the size of the applicator. Therefore, in order to ensure a compact applicator, particularly for use by children or young adults, Figures 3 to 16 The embodiment of provides a more advantageous alternative.

[0234] In embodiments employing a booster spring, the booster spring can activate upon full needle insertion and can be configured to facilitate retraction of the needle / cannula assembly, leaving the sensor behind and mounted in the sensor housing. However, upon activation of the booster spring, a considerable amount of force may be released. This force can cause significant acceleration of the internal needle hub against the cannula hub, potentially generating vibration or amplifying any existing oscillations in the mechanism. In embodiments, various design parameters of the booster spring can be adjusted to alter the spring's acceleration profile and thereby reduce or avoid any sudden acceleration upon activation. Embodiments can thus reduce or avoid any vibration imparted to the mechanism by the booster spring during retraction, providing safe and reliable retraction. For example, some embodiments may employ a variable-pitch booster spring, a variable-diameter (e.g., conical) booster spring, a variable-diameter wire booster spring, or multiple booster springs (e.g., one within another, or multiple springs in series) to achieve these goals. Furthermore, different materials and / or material processing techniques can be used to achieve the desired spring constant and thereby achieve these goals.

[0235] Generally speaking, Figures 3 to 16 The embodiment of provides an alternative example, wherein the additional force is provided by a supplementary stored energy source, which allows for more efficient insertion and retraction. Other embodiments of supplying additional force in a compact design will also be understood, and several of these embodiments are described below with respect to Figure 28 and 34 However, to achieve the same goal of efficient insertion and retraction, other alternatives may be employed. These involve having the user supply a portion of the force necessary for insertion and retraction, and these are referred to as manual or semi-manual alternatives, and several of these are also described below, with particular reference to Figure 21 to 2 4. In yet another alternative, the applicator mechanism may be made more efficient, or may be configured in a different manner, wherein the increased efficiency or different configuration eliminates the need for additional force, or otherwise reduces the need for force distribution, such as to facilitate removal of the cannula. Figure 20 、 25 Several of these alternatives are described in Figures 27, 32, and 33. The systems and methods described below address a variety of these possibilities. In some cases, a combination of techniques may be employed to perform the necessary insertion and retraction steps. For example, Figures 29 to 31 Embodiments are illustrated where additional force can be supplied, where the system can be made more efficient, and where the user's force can be employed.

[0236] As an example of a system configured to obviate any need for additional force, and with particular reference to Figure 20 , the sensor wire can be pre-inserted into the seal via the cannula. Figure 20In this embodiment, for example, the sensor line is inserted through a cannula that passes through the seal 24 located on the seal carrier 26. In this case, the transmitter insertion force is not required to perform the seal, but the transmitter insertion force can still be used to stabilize the seal and sensor line system. Moreover, for example, the systems and methods of application 13 / 826,372, incorporated by reference above, and particularly the Figure 3 Applicators A and 3B can be used to insert the thread into the sealing system described herein.

[0237] Figure 20 Implementation plan and Figures 3 to 16 One difference between the implementations of Figure 20 The embodiment includes only one spring 142. And in Figure 20 In the case that one of the springs is a coiled or helical wire spring, rather than Figure 6 Clock spring 54. It should be noted in this regard that clock springs or power springs generally provide a flatter torque performance curve over the spring's operating range and can have a lower k-factor than coil wire springs. However, any spring that provides a torsional force can be used, including both wire springs and clock springs. Furthermore, any suitable mechanism configured to convert a rotational force into a linear force can be used. The solutions described herein improve upon many prior art devices, as prior art devices generally do not perform as many actions as required with only one or two springs, such as needle and sensor insertion, needle retraction, cannula retraction, and the like. Figure 20 Advantages of the embodiment include high availability and smooth sinusoidal mechanism motion as caused by the scotch yoke.

[0238] As an example of using manual or semi-manual or user supplied force, and with particular reference to Figure 21 , the wheel 144 coupled to the torsion spring can be used for insertion as in the prior embodiment, but can provide separate manual forces for one or more individual steps. Figure 21 In the embodiment of the present invention, for example, the retraction step can be performed manually rather than using a spring-assisted method. Specifically, button 146 is coupled to a bar 154 that is configured to prevent rotation of wheel 144 until button 146 is moved in the proximal direction. For example, movement of the bar can push aside a peg or stop that previously prevented rotation of the wheel. Other techniques will also be appreciated.

[0239] Once the button 146 is moved in the proximal direction, the bar 154 no longer prevents the rotation of the wheel 144, and in the same manner as described above, the needle and sensor wire can be inserted into the body using the force of a torsion spring (not shown) coaxial with the wheel 144. Specifically, a yoke 158 is shown which can be driven downward by rotation of the wheel 144, thereby advancing the needle and sensor into the body. This aspect is also illustrated in FIG. 24 , where the initial movement of the button 146 to the right causes the needle and sensor wire to be inserted into the body. FIG. 24A to FIG. 24B The shift also causes the yoke 158 to move toward the button (to the left in the figure). A push rod mechanism as described above or in the applications incorporated by reference can be used to maintain the sensor in the body during needle retraction. The needle can be retracted by manually retracting the button or by using a torsion spring of the yoke 158 and continuous rotation of the wheel 144. Figure 24B As shown in FIG, the lowest point of the yoke is illustrated by the dashed yoke 158, while the initial retraction of the needle is illustrated by the solid yoke. To retract the cannula, the button 146 can be moved to engage the yoke; by continuing to move to the right, as shown Figure 24C and 24D The cannula can be removed from the seal and seal carrier as shown in . Manual cannula retraction can be particularly useful because it is generally the step that requires the most force. Figure 23 The applicator 160 is illustrated employing manual retraction.

[0240] The button 146 may be provided with an indentation that is biased in a manner to assist the user in positioning the button 146 as indicated by arrow 152 (see FIG. Figure 21 ) in the direction indicated by the , e.g., to remove a needle and cannula from the sealing system, seal carrier, and housing.

[0241] Figure 22 The resulting force distribution is shown. In the initial part of the movement indicated by segment 12", the force distribution is the same as that of line 12, since the same type of spring causes the movement. However, during the retraction phase, the available force rises to line 155, exceeding the force necessary to perform the remainder of the movement required by the step. Although Figure 22 The center line 155 indicates a constant level of force, but it will be understood that, where caused by a manual mechanism, the force is essentially arbitrary and is limited to the force that a user can bring to bear on the button 146 .

[0242] Other means may also be employed to convert the rotational energy (and therefore the rotational force) stored in the torsion spring into the more linear translation required in the sensor placement system. In other words, a basic requirement of the applicator system is that it is configured to perform insertion of the sensor in a percutaneous manner, such that a portion of the sensor is in the interstitial space in the subject in vivo (the distal portion) and a portion of the sensor (the proximal portion) is outside the body. In some cases, the sensor may have sufficient breaking strength and a sharp tip to be able to penetrate the skin itself using the systems and methods disclosed herein or in the applications incorporated by reference. In other cases, including in most embodiments disclosed herein, a needle is used for insertion of the sensor, and the sensor travels with the needle during insertion and remains in the body while the needle is retracted, i.e., the sensor is left in place. In other cases, as will be described, a needle is used to perform insertion, but the sensor wire has sufficient breaking strength to penetrate even deeper than the needle through the interstitial region of the patient.

[0243] Therefore, the generally required motions applicable to most embodiments are those of insertion and retraction, i.e., insertion of the insertion needle and sensor assembly and retraction of the removal needle. In some cases, the needle is provided with greater breaking strength, and the needle motion itself is significantly facilitated by the incorporation of a cannula, which is generally a low tube. For example and as Figures 3 to 16 In embodiments, rather than having the needle penetrate the seal, the cannula can be stationary within the seal during insertion, allowing the needle to be easily moved through the cannula to perform the sensor insertion step. However, to achieve a seal, the cannula will be removed, and this often encounters significant removal forces as the cannula is removed from the elastomeric seal. To reduce the number of movements required, in many embodiments, the cannula is removed simultaneously with the needle. For example, with respect to Figures 3 to 16 In the embodiments of the present invention, the cannula hub latches onto the internal needle hub, which is pushed in the proximal direction by the assist spring. In this way the cannula is removed. However, in all of these embodiments, a back and forth linear motion is required. If the energy is stored via a torsion spring, then a conversion from rotational force to linear force is also required. In the above embodiments, a scotch yoke is conveniently used. However, other devices and techniques can also be used. As long as the back and forth motion can be performed, the rest of the system can be as described above with respect to the applications incorporated by reference above or with respect to Figures 3 to 1610. The present invention provides a method for providing ...

[0244] As an example of an embodiment in which overall efficiency is increased thereby eliminating the need for additional force or drive mechanisms or stored energy sources, and see Figure 25 , the applicator 224 may include a slider crank mechanism 222 that converts rotational force into linear force in the same manner that a slider crank on a sewing machine converts linear motion into rotational motion. Figure 25 In the , the crank slider is driven from the bottom. Figure 26 In FIG, the crank slider is driven from the top, and specifically the crank slider 228 is driven by the rotation of the wheel 226. The crank slider 228 can be coupled to a point position on the needle / hub assembly 232, or can be coupled within its yoke 234.

[0245] Without wishing to be bound by theory, it is believed that the slider-crank mechanism is generally more efficient than the scotch yoke mechanism and subsequently results in a reduction in energy loss during the deployment cycle. In some embodiments, due to the reduction in energy loss, the slider-crank mechanism can be employed without an assist spring. Figures 3 to 16 In a similar embodiment, a similar button latch system may be employed to prevent rotational movement until such time as a user has activated a button, at which time a slider crank mechanism may be employed to insert and retract the needle and / or cannula in a similar fashion as described above.

[0246] In the same manner, and for the same purpose of increasing the efficiency of the device, and see Figure 27The device 242 in FIG. 2 may employ a rack and pinion mechanism to provide reciprocating or back and forth motion. Specifically, the rack 244 is coupled to an external needle hub, indicated by a yoke 248 in the figure. Of course, the attachment for coupling between the rack 244 and the external needle hub need not be a yoke, but may be any type of attachment. A pinion 246 is shown having teeth 252 on only one portion. Rotation of the pinion 246, caused by, for example, a torsion spring, thus causes movement of the rack 244. As shown, if the pinion 246 were to rotate clockwise under the influence of the torsion spring, the teeth 252 of the pinion 246 would engage the teeth 254 on the rack, thereby driving the rack downward. As the pinion 246 continues to rotate, the teeth 252 eventually engage the teeth 256 on the rack, thereby driving the rack (and the object to which it is attached) upward in the proximal direction, thereby completing the motion required to perform sensor and needle insertion and needle retraction. The remainder of the configuration may be as described above in Figures 3 to 16 described in .

[0247] One exemplary benefit of a rack and pinion mechanism is that it can offer advantages over a scotch yoke mechanism in some embodiments. For example, scotch yoke mechanisms typically have low and high torque points in their cycle, which can make them susceptible to stalling where high torque is needed. A rack and pinion mechanism generally provides a more constant torque and can be generally more efficient at transferring torsion spring energy into linear motion.

[0248] As another example of an embodiment in which an additional force is supplied, Figure 28 Another mechanism is shown that can be used to perform a reciprocating back-and-forth motion for insertion and retraction purposes. Specifically, applicator 262 includes an outer needle hub 266 containing a first compression spring 272, and an inner needle hub 268 containing a second compression spring 274. In one embodiment, spring 272 is maintained in a compressed state until use, and spring 274 is also maintained in a compressed state until use. Spring 272 can be coupled to the outer needle hub at a proximal end, and spring 274 can be coupled to the inner needle hub at a distal end.

[0249] Activation of the trigger can then cause the release and subsequent extension of spring 272, thereby driving the needle and sensor into the body. In the same manner as described above with respect to activation of the booster spring, for example using a pusher hub latched into a portion of the applicator housing, spring 274 can be activated, thereby causing the needle to retract out of the body while leaving a portion of the sensor within the body.

[0250] Figure 29Another embodiment of the drive mechanism 264 is shown, this embodiment employing only a single compression spring 278 within the applicator 276. In this embodiment, the spring 278 provides both a downward insertion force (distal, into the body) and an upward retraction force (proximal, out of the body) and is coupled to the applicator 276. Figure 28 Compared to the embodiment of the present invention, the present invention has the manufacturing benefit of eliminating one part. In this case, the spring 278 remains in a preloaded fully compressed state. The distal wall 277 that holds the spring against expansion in the distal direction is then removed or moved distally, and the spring is thereby expanded by being driven away from the proximal wall 279, which holds the spring against expansion in the proximal direction. During this insertion step, the spring releases approximately half of its stored energy to drive the needle into the body. The spring is now still half loaded, with the distal wall in the bottom position. The proximal wall is then released to use the second half of the spring energy to drive the needle (and cannula, if used in a given embodiment) in the proximal direction away from the distal wall.

[0251] In addition to manual retraction, another embodiment includes a user pre-loading step. This embodiment can be a variant of a single compression spring. However, for manual insertion, the spring can be placed on the shelf in a half-loaded state. The initial force input by the user pressing the plunger fully loads the spring. Then, the release is as described above with respect to Figure 29 The same is true for the single spring embodiment described.

[0252] One benefit of the manual insertion embodiment is that only a single coaxial spring is required, thus significantly reducing costs. In use, the user depresses the plunger against the resistance of the spring in the same way as compressing a button on a ballpoint pen against a spring. The needle is not activated before the plunger reaches the bottom of its stroke. When at the bottom of its stroke, the spring releases, and the needle and push rod are pushed forward under the skin. This position is maintained until the user releases the plunger, at which point the plunger retracts, thereby pulling the needle and cannula back and placing the sensor. As in other embodiments, the push rod can remain in the distal or bottom position, causing the sensor to be placed in the body. The user can then remove the applicator and install the transmitter.

[0253] Advantages of the user-preloaded insertion embodiment include lower cost and fewer components, as well as avoiding partial deployment because activation does not occur until the user fully depresses the plunger. Another significant advantage of manual insertion is that the spring is not fully preloaded, but rather half-loaded by the user just before activation. In this way, problems with sizing components for sustained loads in plastic components, such as creep, are avoided.

[0254] Figure 30Graph 210 in FIG. 1 illustrates an exemplary force profile, wherein it is seen that only half the force is applied before the plunger is at the bottom travel range, as shown in segment 202, but at that point (point 212), the force increases to a maximum value, caused by the spring being compressed to its maximum displacement (F = -kx max ) causes the spring to relax as it expands, as shown by segment 204, and the resulting force decreases linearly. At point 208, the user releases the plunger, causing additional spring force to enter the system, indicated by the force rise in graph 210. As the spring expands toward equilibrium, the force continues to decay, as shown by segment 206. The force is then used to retract the cannula and needle. As can be seen, the available force exceeds the force required to pass all points of insertion and retraction.

[0255] Figure 31 Flowchart 214 illustrates a method of use, wherein the first step is for the user to press the button plunger (step 216). No action occurs until the button reaches the bottom of its stroke. At the bottom of the stroke, the spring releases, which inserts the needle, sensor, and push rod (step 218). After the user pressure on the plunger is removed, the plunger begins to move in the opposite direction, causing the needle and cannula (in embodiments that include a cannula) to retract (step 222). In some cases, the user's pressing of the plunger can provide the force required to insert the needle and sensor. The sensor is deployed during needle retraction, while the push rod inhibits sensor movement.

[0256] Figure 28 and 29 The embodiments of the invention and manual insertion provide certain benefits over the above described scotch yoke mechanism in some cases. In particular, the torsion spring in the scotch yoke mechanism sometimes cannot provide enough energy to perform all deployment functions. Figure 28 and 29 As well as manual insertion, the use of compression springs provides a one-way assembly process which is convenient for automation. Figure 28 In the embodiment of the present invention, the dedicated springs for the "needle in" and "needle / cannula out" functions allow the springs to be custom designed and tuned according to the system requirements. In addition, the springs can be associated with certain assembly and manufacturing advantages.

[0257] Figure 32 Another embodiment of a drive mechanism is illustrated, this embodiment allowing for an even wider range of movement and motion of component parts. Specifically, the drive mechanism 302 includes a barrel cam 306 having an axle 304, which can be driven by, for example, a torsion spring or user motion. Figure 32 The embodiment of can be particularly useful for solving the problem of moving multiple components that need to change direction to perform sensor insertion depending on the embodiment. A barrel cam can be used that contains multiple tracks that control the movement of each component independently of each other and thus can be more reliable and controlled. In this way, it can be made Figure 32 The implementation scheme is particularly effective.

[0258] The barrel cam 306 performs the conversion of rotational force into linear or translational or longitudinal force. The barrel cam 306 includes one or more channels, shown as channels 308, 312 and 314. Parts such as the outer needle hub, inner needle hub, cannula hub, push rod hub and the like are driven by corresponding nodes that straddle the channels or tracks of the barrel cam 306. Specifically, node 316 is driven by the rotation of channel 308. Node 318 is driven by the rotation of channel 312. Node 322 is driven by the rotation of channel 314. The linear position of the needle hub, push rod hub and cannula hub can be controlled by the shape of the track in the barrel cylinder. In this way, component parts can be inserted and retracted as needed without the hubs falling off. As the cylinder rotates, each hub moves linearly independently of each other.

[0259] Figure 33 Another embodiment of a high efficiency drive mechanism is shown. This drive mechanism 324 includes a wheel 326 configured to cooperate with a first yoke 328 and a second yoke 332 to move the vehicle in a manner similar to Figures 3 to 16 The insertion and retraction process is facilitated in the manner described herein. The first yoke 328 is operatively coupled to the needle hub 340 and the push rod hub 338, and the second yoke 332 is operatively coupled to the cannula hub 342. The rotation of the wheel 326 can be driven, for example, by a torsion spring, such as described herein in conjunction with Figure 6 However, in this embodiment, the wheel 326 has a first pin 334 extending therefrom that is configured to engage with the first yoke 328 during at least a portion of the rotation of the wheel 326 and a second pin 336 extending therefrom that is configured to engage with the second yoke 332 during at least another portion of the rotation of the wheel 326. Figure 33 In the embodiment illustrated in FIG, the first pin 334 and the second pin 336 are positioned at different radii around the center of the wheel 326. Figure 33 In the configuration shown in FIG, the push rod hub 338 is fixed relative to (eg, locked to) the first yoke 328 and the needle hub 340, for example as described above in conjunction with FIG. Figure 7 and 11 As the wheel 326 rotates in the clockwise direction, under the influence of the torsion spring, the pin 334 pushes the first yoke 328 and the needle hub 340 in the distal direction as it travels within the first yoke 328. Figure 86, when (or after) the first pin 334 begins to move in the distal direction, continued rotation of the wheel 326 causes the second pin 336 to engage with the second yoke 332 (e.g., enter the second yoke 332). At this stage, the push rod hub 338 disengages from the needle hub 340, allowing the needle hub 340 to move in the proximal direction while the push rod hub 338 remains in the distal position. As the second pin 336 travels within the second yoke 332, it pulls the second yoke 332 in the proximal direction away from the seal carrier 26 and the disposable housing 36, thereby performing the retraction step. In other words, in this embodiment, the wheel 326 causes the first yoke 328 to perform insertion and the second yoke 332 to perform retraction. This configuration can provide the ability to precisely set different insertion and retraction forces as needed using a single torsion spring. The mechanical advantage of the cam can therefore be tuned according to the available spring force.

[0260] exist Figure 33 and 86 In the embodiment illustrated in , the first pin 334 remains engaged with the first yoke 328 while the second pin 336 engages the second yoke 332 and throughout the insertion and retraction process. However, other configurations are possible in which the first pin disengages from the first yoke before or after the second pin engages the second yoke. In an embodiment, one or both ends of the first yoke 328 may be opened to allow the pin 334 to engage with (e.g., enter) and / or be released from (e.g., exit) the first yoke 328 at a desired rotational position of the wheel 326. Similarly, one or both ends of the second yoke 332 may be opened to allow the pin 336 to engage with (e.g., enter) and / or be released from (e.g., exit) the second yoke 332 at a desired rotational position of the wheel 326. Figure 33 and 86 , the second pin 336 is disposed at a larger radius of the wheel 326 than the first pin 334 and extends from the underside of the radially extending arm of the wheel 326. In other embodiments, the second pin can be disposed at the same or a smaller radius than the first pin. In still other embodiments, the same pin can be configured to engage the first and second yokes during separate portions of the wheel's rotation.

[0261] Figure 87 and 88 A drive mechanism 350 according to yet another embodiment is shown. The drive mechanism 350 includes a wheel 352 configured to cooperate with a yoke 358 to rotate the drive mechanism in a manner similar to Figures 3 to 16 The insertion and retraction process is facilitated in the manner described herein. The yoke 358 is operatively coupled to the needle hub 356 and the push rod hub 354, as well as to the cannula hub 362. The rotation of the wheel 352 can be driven, for example, by a torsion spring, such as described herein in conjunction with Figure 6 However, in this embodiment, as Figure 88As shown in FIG, the drive mechanism 350 also includes a booster spring 364 configured to facilitate the cannula retraction process. Figure 87 and 88 In the configuration shown in FIG, the push rod hub 354 is fixed relative to (eg, locked to) the needle hub 356, for example, as described above in conjunction with Figure 7 and 11 356 . As wheel 352 rotates in a clockwise direction, under the influence of the torsion spring, pin 360 advances within yoke 358 and pushes needle hub 356 in the distal direction, while cannula hub 362 remains stationary (e.g., fixed in place or position). After pin 360 reaches its distal-most position, continued rotation of wheel 352 causes pin 360 to advance in the opposite direction within yoke 358, pulling yoke 358 and needle hub 356 in the proximal direction. At this stage, pusher hub 354 disengages from needle hub 356, allowing needle hub 356 to move proximally while pusher hub 354 remains fixed or locked in the distal position. Simultaneously or shortly thereafter, a release member is activated, which releases cannula hub 362 from engagement with the base of lower housing 40, thereby actuating assist spring 364. As the booster spring 364 expands, it pushes the cannula hub 362 away from the seal carrier 26 and disposable housing 36, thereby facilitating the retraction process in conjunction with the torsion spring. This configuration also provides the ability to precisely set different insertion and retraction forces as needed. Variations on the booster spring may also be employed, with the embodiment described using a Figures 3 to 16 . As mentioned above, in some cases, the cam can be made larger and the needle can be fully inserted and retracted by the torsion spring. The booster spring can be independently connected to the cannula hub and can be activated while the needle is still in motion and driven by the wheel. The cam can be smaller in this embodiment because it does not fully retract the needle from the seal. The booster is activated when the torsion spring has reached the end of its travel. The booster spring is attached to the needle hub and drives the needle (which picks up the cannula and cannula hub) out of the seal.

[0262] See now Figures 93 to 96 , illustrates an applicator assembly 20c (with its upper housing and other components removed for illustration purposes) configured in accordance with an alternative embodiment. Figure 9386c and a push rod 86c. The device 20c is shown in a resting state prior to deployment. The device 20c includes an outer needle hub 66c, an inner needle hub 68c, and a push rod 86c. The device 20c further includes a disposable housing 36c and a seal carrier 26c having a two-part configuration. The seal carrier 26c includes a first portion 27 that is operatively coupled to the disposable housing 36c at a hinge 28, at least prior to deployment of the device 20c. The seal carrier 26c also includes a second portion 29 that is coupled to both the push rod 86c and the needle 72 and is disposed separately from the first portion 27 and at a proximal end thereof prior to deployment. The second portion 29 includes at least one seal 24. The first portion 27 and the second portion 29 are both disposed at the same angle relative to the plane of the disposable housing 36c.

[0263] During the insertion process, the outer needle hub 66c, the inner needle hub 68c, and the push rod 86c move in the distal direction along with the second portion 29 of the two-part seal carrier 26c. The second portion 29 slides into engagement with the first portion 27 and eventually snaps into engagement with the first portion 27. At this stage, the needle 72 and sensor wire are deployed into the patient's skin.

[0264] In a configuration with a two-part seal carrier, adverse interactions that could affect the required force or sensor positioning (e.g., friction or seal backlash) are prevented. This is achieved by eliminating relative movement between the seal component and the needle during the insertion phase of the cycle. This also has the additional benefit of reducing component count (e.g., eliminating the cannula) and maintaining a smaller lumen in the seal, which can have sealing benefits.

[0265] Figure 94 The device 20c is shown just after deployment, wherein the outer needle hub 66c, the inner needle hub 68c, and the push rod 86c have been driven in the distal direction, for example, by a drive mechanism including a torsion spring, a scotch yoke mechanism, a booster spring, and / or any other suitable drive mechanism, for example, as described herein. Under the continued influence of the torsion spring (or other drive mechanism), the inner needle hub 68c begins to retract and pull the needle 72 in the distal direction, while the outer needle hub 66c and the push rod 86c remain fixed in the distal position. Figure 95 As shown in FIG, at this stage the assist spring 74 may be activated to facilitate the retraction process in conjunction with the torsion spring. Once the needle 72 is retracted from the seal 24, the seal carrier 26c is free to rotate downward (e.g., under gravity or spring force) into the deployed position, ready to receive the transmitter.

[0266] Figure 34Another embodiment according to the principles of the present invention is shown in the figure, in which additional energy is supplied and in which a dual spring variant is used. In this case, dual constant force springs 192 and 194 are used instead of compression or tension springs. The use of constant force springs generally provides a different output force curve.

[0267] In all of the embodiments mentioned, a detrimental phenomenon known as "slingshot" can occur when the cannula 78 is removed from the seal 24, and much of the effort in systems and methods according to the principles of the present invention is directed toward reducing or eliminating slingshot. Specifically, when the cannula is removed, the seal, typically made of an elastomer, is pulled by the cannula due to friction at the contact point (actually, the contact cylinder). Consequently, a cylindrical portion of the seal, typically inside the seal and adjacent to the cannula, is temporarily pulled by the cannula during cannula removal.

[0268] As the cannula emerges from the seal, the lack of frictional "pull" of the cannula on the seal causes the seal to rebound in the distal direction. Depending on the configuration, the rebounding ("slingshot") seal may frictionally contact the sensor wire and / or needle and urge it forward, thereby adversely affecting the placement of the contact point on the sensor wire relative to the contact puck. For example, the slingshot can result in a position change of over 100 mils, compared to the puck diameter, which can be, for example, 80 mils, and the distance between the pucks, which can be, for example, 215 mils.

[0269] Some ways to counteract seal slingshot include modifying the seal to reduce its frictional contact with the cannula. These methods are discussed below. Another way to counteract seal slingshot is to perform an action with the cannula to ease its removal from the seal, or at least to perform an action that causes the seal to slingshot less. See Figure 35 and 36 One such method is to rotate the cannula during removal. In both figures, the cannula 78 is caused to rotate by a torsion spring 406, but it should be noted that the rotational force on the cannula can be caused by many different components, including the use of a cam that is rotationally coupled to the cannula. Figure 35 In FIG, a cannula driver 402 is disposed at one end of the cannula and is shown as being driven by a torsion spring 406 via a connecting rod 408. Figure 36 In FIG, the cannula 78 is caused to rotate by a cannula driver 404 disposed on one side of the cannula, and which is driven from a torsion spring 406 through a link 412. In one embodiment, the cannula is rotated before and during removal of the cannula, e.g., with a cycle time of less than 500 ms.

[0270] The amount of rotation required can be small, and it only needs to rotate during the time immediately before the cannula is removed until most or all of the cannula is removed. In one embodiment, and without wishing to be bound by theory, it is believed that in the absence of rotation, the static friction and adhesion between the cannula and the seal must be overcome so that the seal is not pulled by the cannula. If the cannula is caused to rotate, the static friction and adhesion have been overcome, and the only force required is the force caused by dynamic friction. Assuming the normal force is the same, since dynamic friction is generally less than static friction, the cannula force on the seal during removal is much smaller. The relative motion between the seal and the cannula about the axis of rotation does not cause deformation of the seal elastomer about the longitudinal axis. Therefore, the slingshot effect can be minimized by breaking the static friction and adhesion in the axis of rotation.

[0271] It will be appreciated that the cannula drive may be comprised of a number of devices, including those driven by the same energy source that performs insertion and / or retraction, devices specifically dedicated to this purpose, or the like. These devices may include cams, electric motors, and the like.

[0272] In addition to rotating the cannula (or causing it to perform another similar motion, such as vibrating it) to achieve the goal of reducing seal slingshot, another way to specifically reduce the effect of seal slingshot on the sensor wire is to retract the cannula before retracting the needle. In this way, the seal slingshot or "kickback" contacts the needle and does not contact the sensor wire itself. The needle shields the sensor wire from the slingshot effect.

[0273] See Figure 37 Flowchart 414 shows the steps of this embodiment of the retraction sequence. The first step is the needle retracting but remaining in the patient's body (step 416). The next step is the cannula being picked up by the moving needle in the manner described above, but the needle remains protruding from the cannula by a certain length, for example 1 mm (step 418). The final step is the cannula exiting the seal, followed shortly by the needle exiting. This embodiment may be similar to Figures 3 to 16 but in which the needle is made slightly longer.

[0274] Figure 37 The embodiment of can provide several benefits. Without wishing to be bound by theory, it is noted that the kink in the needle (described below with respect to FIG. 38 ) prevents forward movement during most of the seal recoil during the retraction step. Additionally, seal recoil is allowed while the sensor wires are still protected by the needle.

[0275] In yet another embodiment, and referring to Figures 38A to 38C , the length of the needle can be reduced so that the needle does not penetrate as deep as the sensor. The strength of the needle is generally required to penetrate the subject's skin, but once through the skin, even the breaking strength of the sensor wire is generally sufficient to allow further penetration into this interstitial region, for example at least 2 to 3 mm beyond the needle tip. Figure 38A 38 , needle 422 is shown penetrating the subject's skin. The needle contains a sensor wire 424 within it, and in FIG38 , a kink 426 and a push rod 428 are also visible.

[0276] exist Figure 38B In FIG, the sensor wire 424 has been pushed out to a greater distance (more distal end) than the needle 422. The needle is retracted in Figure 38C , resulting in the sensor wire 424 being placed into the body.

[0277] This implementation can be modified by Figures 3 to 16 38 , including extending the sensor past the location where the trauma from the needle occurs, reducing sensor artifacts and other deleterious signal effects such as "first day noise". In addition, this embodiment allows for a reduction in the height of the applicator, which is driven at least in part by the length of the needle. It should be noted in this regard that the needle is driven approximately 1 to 6 mm below the skin and the sensor is driven approximately 4 to 15 mm.

[0278] In an embodiment, the needle may be a single lumen needle having a single bevel at its tip, e.g. Figure 99 and 100 In some embodiments, the trailing edge or heel of the needle tip (i.e., Figure 99 The needle tip in FIG (the portion to the right of line AA) may undergo special processing during manufacturing, such as additional sandblasting at either or both of the inner and outer edges, to remove any fine burrs and avoid coring or other trauma to the patient's skin. Embodiments can thus avoid inaccurate glucose readings that might otherwise result from cellular damage to the patient's tissue during sensor deployment.

[0279] In some embodiments, the needle may be a multi-lumen needle, e.g. Figure 101 4. Needle 456 is shown in FIG. Needle 456 includes a metal outer lumen 458 and a polymer inner lumen 460. Embodiments incorporating an inner lumen comprising a compliant material, such as a polymer, may be used to limit or minimize tissue trauma.

[0280] In some embodiments, the needle may be a curved, C-shaped, or Tuohy needle. Figure 107As shown in FIG, needle 1010 includes a wall structure 1012, a cutting edge 1014, and a blunt profile 1016. Needle 1010 can advantageously be used to deliver a sensor 1018 (e.g., an analyte sensor, such as a glucose sensor) through the outer skin layer and into the sensor depth in a less invasive manner than is performed by prior art needles. In the needle design, the size of cutting edge 1014 is balanced against the distal portion of wall structure 1012 having blunt profile 1016. Thus, needle 1010 is able to cut the more durable outer skin layer (first phase) and then gradually widen the open incision for further advancement into the subcutaneous layer with minimal tissue trauma (second phase). When the needle, along with the sensor therein, is fully advanced, the needle and sensor are then separated, and the needle is retracted, leaving sensor 1018 in the desired position. Early testing has shown a reduction in "immersion and recovery" events (as well as a reduction in the average duration of events) where glucose sensors were delivered using the needles described herein.

[0281] The term "needle" as used herein should be interpreted as encompassing any delivery device that can contain a sensor 1018 for delivery to an appropriate depth. The "needle" can have any of a variety of shapes with respect to its wall structure 1012. For example, the wall shape can be cylindrical with a circular cross-section, or can have a V-shaped, square, or rectangular, or even some irregular cross-section. The wall shape also need not be an extruded shape with the same cross-section along its axis. For example, the wall shape can start as a cylindrical tube with a circular cross-section at the proximal end and then change to a V-shape (in cross-section) as it approaches the distal end. The wall shape can also define a slot or various openings along its length, such as a slot giving it a C-shape in cross-section. (The open cross-section of the C or V-shape provides clearance for attachment of, for example, wiring.)

[0282] Generally speaking, however, the wall structure 1012 defines some inner (relative to some outer surface of the wall) dimension (e.g., width or diameter) that supports or contains the sensor 1018 for subcutaneous delivery. For example, in a V-shaped cross-section, the inner portion of the V near its base has a diameter occupied by the sensor stored between the two inner wall surfaces. Thus, the "dimension" is defined by the location that the sensor occupies (or will occupy) during delivery in or on the wall structure 1012 of the needle 1010. The term "needle" also encompasses other devices (with different names) that share a similar wall structure and function (e.g., delivery of an implantable device), such as a tube, channel, cannula, catheter, or blunt dilator having a recess or opening for deployment of an implantable device (e.g., a sensor).

[0283] The wall structure 1012 of the needle 1010 is Figure 107The embodiment has a tubular shape that defines a central opening 1022 having a central axis 1020. The wall structure 1012 is formed by generally Figures 109 to 111 1 or 2. The proximal end of the wall structure 1012 retains its stock tubular shape and has an outside diameter of, for example, 0.018 plus 0.001 or minus 0.0005 inches. Preferably, the inside diameter is an internal dimension sized to contain the cross-section of the sensor 1018 for its delivery. The sensor 1018 has a cross-sectional diameter that is smaller than the diameter of the central opening 1022. The size and shape of the central opening 1022 can vary depending on the size and shape of the sensor 1018 being delivered. As described above, the needle 1010 can have a wall structure 1012 having a shape that varies axially and in cross section. For example, the wall structure cross section can have a rectangular, C-shaped, or V-shaped shape, as will be discussed in more detail below.

[0284] In some embodiments, the outer diameter of the wall structure 1012 at, for example, the proximal end can be approximately 0.0135 plus 0.001 or minus 0.0002 inches. The outer diameter and thickness of the wall structure 1012 reflect a balance between column stiffness and minimization of wound size for the needle to pass through the patient's skin. In certain embodiments, the diameter of the wall structure 1012 is minimized, but not to the extent that the needle 1010 readily buckles under the expected axial load from needle insertion.

[0285] In one aspect, the wall structure 1012 has a length configured to hold and protect the sensor 1018. In the case of one type of subcutaneously delivered glucose sensor, for example, the wall structure 1012 has a length of approximately 2.31 ± 0.02 inches.

[0286] The strength (e.g., breaking strength) of the wall structure 1012 is determined in part by its material composition. A range of materials may be used, such as steel (e.g., stainless steel), ceramic, titanium, tantalum, nickel, nickel-titanium, iridium, silver, palladium, platinum-iridium, iridium, ceramics, composites, and combinations or alloys thereof, and / or the like. Polymers that may be used include, but are not limited to, polycarbonate, polymethacrylic acid, ethylene vinyl acetate, polyester, polytetrafluoroethylene, and the like. Fluoropolymers, polyethylene, polypropylene, high-density polyethylene, nylon, polyethylene terephthalate, and polyester, combinations thereof, and the like. Harder materials such as stainless steel (SS304 with a full hard temper) can store more deformation energy than many other materials and have a higher modulus (190 to 203 GPa Young's modulus) and elastic limit (205 to 310 MPa), and therefore have good hardness and resistance to buckling and permanent (plastic) deformation. This helps maintain the shape of the needle (and its ability to deliver the sensor) during penetration of the skin to the depth of the sensor. Moreover, steel has the advantage that it can be processed (shaped, filed, ground, etc.) to produce a sharper edge than many other materials. In addition, steel tends to hold its edge better, and the above-mentioned modulus and energy storage capacity keep the edge sharp during its use.

[0287] The insertion force and buckling strength of needle 1010 have been determined. Needle 1010 was inserted into a 10N Syndaver at 45 degrees at 1 inch / minute. Peak insertion force was measured using a 10N load cell. Insertion force was measured over 8 attempts with an average of 0.22 lbf, a minimum of 0.156 lbf, a maximum of 0.298 lbf, and a standard deviation of 0.0505. Insertion force was also measured for conventional needles with a range of 0.163 lbf and 0.237 lbf, with an average of 0.191 lbf and a standard deviation of 0.0239.

[0288] The buckling strength was tested by compressing the needle 1010 against an impenetrable object (a metal plate) and measuring the axial force required to buckle the needle using a 10N load cell. The buckling strength of the needle 1010 was (for 8 samples) an average of 2.505 lbf, with a minimum of 2.185 lbf and a maximum of 2.280 lbf and a standard deviation of 0.2189. For conventional needles, an average of 2.458 lbf was measured with a minimum of 2.158 lbf and a maximum of 2.755 lbf.

[0289] The ratio of the buckling strength as a ratio to the insertion force ranges from about 7.3 to 14.6 times the insertion force.Thus, the needle 1010 is able to withstand buckling even in the presence of some relatively high percentage blunt profile of dilation of the skin opening.

[0290] The "center axis" is a reference point for the amount and positioning of the cutting edge 1014 and the blunt profile relative to the proximal portion of the sensor 1018 (or where it would be if the sensor were within the needle 1010). Figure 107 In the embodiment of the present invention, the central axis of the wall structure 1012 is defined by the unbent proximal end of the wall structure. That is, the central elongated axis of the proximal unbent tube of the wall structure shown by the interrupted dashed line is the central axis 1020.

[0291] The central axis 1020 is not limited to a linear shape. Generally speaking, the central axis will be defined by a line passing through a series of points, where the points are the centroids of a series of cross-sectional slices of the proximal end of the sensor 1018. Thus, when the path of the sensor 1018 bends or curves, the central axis 1020 will follow. (The "centroid" is the average position of all points in a shape. For a cylindrical sensor, it is the center of the circular cross-section. However, a sensor need not have any particular cross-sectional shape to define a central axis; even irregular cross-sectional shapes have a centroid.) Generally speaking, then, the central axis defines the center position of the composite path of the sensor 1018 approaching the edge and the blunt contour, serving as a reference point for positioning the cutting edge 1014 and the blunt contour 1016.

[0292] The central opening 1022 is an opening in the center defined by a closed boundary wall structure, such as Figure 107 The opening defined by the tubular portion of the needle 1010 wall structure 1012. The central opening 1022 is an opening configured (by sizing, finishing, etc.) to receive a major dimension (eg, diameter or width) of the sensor 1018 to be delivered.

[0293] Return to view Figure 107 、 108 and 112, the distal end of the wall structure 1012 has formed thereon a cutting edge 1014 and a blunt profile 1016. The blunt profile 1016 may include a bend 1030 in the wall structure 1012 of the needle 1010. Prior to application of the bevel and cutting edge 1014, the bend 1030 is formed in the tubing used to create the wall structure 1012, as shown. Figure 109 For a cutting edge 1014 configuration having a primary bevel angle ranging from 3 to 12 degrees and (optionally) a secondary bevel angle ranging from 8 to 24 degrees, the bend angle may range from about 5 degrees to about 30 degrees, in increments of one degree.

[0294] The bend can be any of a variety of angles, depending on the desired angle of entry for the tip of the cutting edge. Preferably, the bevel angle of the cutting edge 1014 is balanced with the amount of blunt profile 1016 seen by the skin when the skin is penetrated. For example, the amount of blunt profile and cutting edge "seen" by the skin is the projected area occupied by the blunt profile and cutting edge when viewed along the central axis 1020. (This captures a measure of the proportion of the blunt and cutting edges that impact the skin as the needle advances along the central axis.) The blunt surface area is the amount of area occupied by the blunt profile of the needle from this view, and the cutting surface area is the amount of surface area positioned opposite the blunt profile, starting with the cutting edge, as again viewed along the central axis 1020.

[0295] Generally speaking, designs with greater curvature (and a larger blunt profile area seen at the insertion site) are more conducive to reducing wound size. However, the degree of curvature (and the size of the blunt profile seen at the insertion site) is limited by the need for some aspect of the cutting edge 1014 to be positioned to penetrate the skin surface and form a hole large enough for expansion without further tearing. Therefore, the bevel angle or other angle of the cutting edge 1014 relative to the central axis balances the amount of angle of the bend 1030.

[0296] A lubricant or other material can be added to the lumen of needle 1010 to facilitate sensor withdrawal. For example, silane, silicone, parylene, or other materials with a low coefficient of friction can be added to the lumen surface of the needle. Coating the lumen wall with a lubricating fluid improves the ease of sensor release without damaging the sensor membrane or otherwise inhibiting sensor operation.

[0297] The cutting edge 1014 may comprise several sharp edges or portions thereof in a composite form or may comprise a single planar facet forming a single sharp edge. Figure 107 and 108 The cutting edge 1014 in the embodiment is formed on a set of beveled surfaces.

[0298] The beveled surface may include a primary or proximal bevel 1024 and a pair of secondary or distal bevels 1026, such as Figure 108 As shown in Figure 107 , the primary bevel can extend at an angle of about 7 degrees relative to a line parallel to the central axis and extending from the outer surface of the wall structure 1012 at the proximal uncurved end of the wall structure. The primary bevel can be at any of a variety of angles, depending on the desired proportions and orientation of the forward-facing cutting edge 1014 and the blunt profile 1016. For example, the primary bevel 1024 can be in the range of about 3 degrees to about 12 degrees, depending on the amount of upstream curvature in the wall structure 1012.

[0299] In one embodiment, the cutting edge 1014 can be defined on a single primary bevel 1024 having an angle within the angle ranges described above, e.g. Figure 110 The angles shown in . ( Figure 110 It is manufactured Figure 111 (This is an intermediate stage in the process of sharpening the needle 1010 in FIG. 1 , but represents where the single-bevel embodiment would stop for sharpening.) The distal edge of this primary bevel 1024 can then be sharpened to form a cutting edge 1014, which is sized in some desired ratio to provide a polished edge and a blunt profile to produce the desired two-stage cutting and expansion, which reduces invasiveness, as well as immersion and recovery. (A more detailed description of how the blunt cutting and cutting surfaces are balanced in terms of their ratios is described above and in more detail below.)

[0300] In some embodiments, for example Figure 107 、 108 111 to 114, two additional secondary or distal bevels 1026 are formed on the distal tip of the wall structure 1012 on the side of the wall structure opposite the bend 1030. Figure 109 and 110 Shown Figure 5 ) With respect to the same reference point, the bevel 1026 is at an angle of about 12.4 degrees, as shown in FIG. Figure 107 The two distal bevels 1026 can also define an angle between their proximal edges, such as Figure 128 and 129 As shown in . Figure 128 An angle of 120 degrees between the proximal bevel edges is shown. Figure 129 A 20 degree angle between the proximal bevel edges is shown.

[0301] The secondary bevel 1026 can vary in its angle to the outer surface line. However, a range of about 8 to 24 degrees balances the ratio of the cutting edge 1014 and the blunt profile 1016 for wound reduction. In some embodiments, the needle can have a 17-degree bend 30, a 7-degree primary bevel 1024, and a 16-degree secondary bevel 1026.

[0302] exist Figure 108 The distance between the closest point of the bevel surface (along the central axis 1020) and the furthest point of the bevel surface is 0.05 ± 0.01 inches. The distance between the closest point of the secondary bevel 1026 and the furthest point of the secondary bevel 1026 is 0.03 ± 0.006 inches.

[0303] Although the set of bevels 1024, 1026 form several axially oriented edges on the distal end of the wall structure 1012, not all of these edges are necessarily sharpened. Rather, the cutting edge 1014 is formed only on the more distal portion of the secondary bevel 1026. Specifically, for example, Figure 113 10. In the embodiment shown, a circle centered on the central axis surrounds the bottom edge of the proximal wall structure 1012 and extends above the bevel. In this embodiment, only the portion of the bevel within the circle is sharpened. Those bevels outside the circle are rounded.

[0304] exist Figure 113In the illustrated embodiment of FIG, the circle has a diameter of 0.018 inches, which is the same diameter as the tube used to form the wall structure 1012. The sharpened portion of the bevel 1026 extends only to the edge of the circle when it is reflected on the secondary bevel 1026. While having the advantage of matching the proximal cross-section of the wall structure 1012, the sharpened portion can be expanded or reduced based on the desired wound size, sensor characteristics, patient variability, etc.

[0305] The remainder of the edges of the bevels 1024, 1026 can be rounded to a smooth, non-cutting edge having a radius of about 2 to 3 thousandths of an inch or more. For example, the heel and other edges of the primary bevel 1024 can be sprayed with a medium to smooth them. Spraying the heel of the bevel (the proximal interior edge that defines the central opening 1022) can smooth it to reduce or eliminate coring, which occurs when the skin is picked up during insertion of the needle 1010 (sometimes also referred to as "coring").

[0306] like Figure 113 As shown in FIG, in some embodiments, the design of needle 1010 balances cutting edge 1014 and blunt profile 1016 to facilitate a two-stage cutting and dilation process for insertion of sensor 1018. Various metrics can be used to define and describe the balance between cutting edge 1014 and blunt profile 1015 in a needle design. For example, Figure 113 As shown in FIG, in one embodiment, the cutting edge 1014 occupies only about 60 degrees (33%) of the 180 degrees of the outer peripheral edge of the bevels 1024, 1026. Generally speaking, the smaller the ratio of sharpened edge to unsharpened edge of the bevels 1024, 1026, the smaller the initial wound before expansion. Variations from 50% of the total sharpened edge down to 20% are possible, in 5% increments.

[0307] In one embodiment, the bend 1030 advantageously repositions or offsets the leading point of a conventional needle (and the initial contact cutting feature) by 0.0112 inches to the opposite side of the circular cross section, such as by Figure 114 and 115 Thus, the tip's deflection pushes it past (0.002 inches, as Figure 113 ) central axis 1020. For example, the needle tip is about 62% of the way across the diameter to the opposite side of the circle. In this way, the central axis 1020 (as with any offset greater than 50% of the diameter or other relevant dimension associated with the location of the sensor) passes over the blunt contour 1016 rather than the cutting edge 1014.

[0308] It should be noted, however, that the advantages of presenting a blunt profile 1016 begin with any size bend 1030 (or other structure or modification) that moves the needle tip and other cutting edge 1014 within the outermost periphery of the surrounding wall structure 1012. Offsetting the cutting edge even 1% away from the outermost periphery and closer to (or past) the central axis than the adjacent outer edge results in some benefit of reduced invasiveness. This positioning presents a blunt profile to the skin during needle insertion. Generally speaking, the further the positioning across the dimension of the needle 1010, the greater the proportion of the area presented to the skin (to the cutting edge) constituted by the blunt profile. For example, in some embodiments, the cutting edge can be repositioned across the dimension in 5% intervals, from approximately 5% to approximately 65% ​​of the dimension. At the same time, a certain amount of cutting edge must be present, or no initial opening in the skin will be formed large enough to expand without being torn by the blunt dissection, hence the concept of a "balance" between cutting and blunt dissection described above.

[0309] While sometimes referred to as a diameter for purposes of the round conduit used for the wall structure 1012 in the illustrated embodiment, the relevant "dimension" is any principal dimension (or "cross-sectional dimension") across the portion of the wall structure 1012 configured to hold the sensor. Another metric that can be used to characterize the ratio of the cutting edge 1014 to the blunt profile 1016 is the projected area dedicated to the blunt profile 1016 projected from a perspective viewed along the central axis 1020. For example, Figure 113 As shown in the view along the central axis, approximately 2 / 3 of the area of ​​the circle surrounding the outer edge of the round wall structure 1012 is dedicated to the blunt profile 1016.

[0310] The various degrees of bend and bevel angles disclosed herein are not arbitrary. Rather, they affect wound size (and therefore immersion and recovery and other foreign body reactions) and sensor deployment, among other things. For example, Figures 118 to 126 Table 1 below shows the changes in bend angle and bevel angle and the effect on the ratio of blunt area (grey) to cutting area (cross-hatched). Figure 120 From as low as 0.85 to as high as Figure 124 The blunt area is 2.74 times the cutting area. It is worth noting that there is an interaction between the bend angle and the bevel angle that determines the final ratio. If a lower bend angle is used, it limits the amount of primary bevel angle before the blunt area drops off sharply and does not reduce wound formation. Ultimately, the blunt area is small enough to approach Figure 127 Similarly, if a high bend angle is used, the cutting edge may not be sufficient to penetrate the dermis during the initial cutting phase. The bend in the needle is also limited by other constraints. If the bend is too severe, the sensor may become lodged in the lumen of the needle and fail to deploy. Alternatively, the sensor may be damaged during deployment.

[0311] Table 1

[0312]

[0313] The relationship of the ratio (blunt surface area / cutting surface area) to the needle bend and primary bevel angle can be defined by the equation: For a primary bevel angle of 5 degrees, ratio (BSA / CSA) = 0.1895 + 0.2266*(bend angle) − 0.004952*(bend angle)². The constant changes with each change in the primary bevel angle. For a primary bevel angle of 7 degrees, ratio = 0.171 + 0.1379*(bend angle) − 0.003095*(bend angle)². For a primary bevel angle of 9 degrees, ratio = 0.1329 + 0.09457*(bend angle) − 0.002286*(bend angle)². The changing constant can be determined for different bevel angles by curve fitting the data in Table 1 above.

[0314] Figures 109 to 111 A partial diagram illustrates how needle 1010 is manufactured. A stock tube is first bent to a predetermined angle (e.g., approximately 10 or 17 degrees) to form a bend 1030 in wall structure 1012. A primary bevel 1024 is then ground or machined to a first desired angle. A secondary bevel 1026 is then ground to a second desired angle. The non-cutting edges are then blasted with material to round them and remove burrs. If necessary, a cutting edge 1014 is generated from the grinding or by further sharpening the axially directed bevel edge.

[0315] See now Figure 114 and 115 The needle 1010 can be designed with a slot 1034 (or multiple slots). These slots can facilitate delivery or removal of the sensor 1018 or help reduce wound trauma. Figure 114 and 115 For example, a slot 1034 is shown that is formed as a window near the distal end of the wall structure 1012 of the needle 1010. The slot 1034 is formed by cutting away a portion (e.g., about half the circumference of the tubular wall structure) and beveling or rounding the wall near the proximal and distal ends (radius of about 0.5 to about 1 inch) for a smooth transition. In the particular embodiment shown, the distal edge of the slot 1034 is about 0.8 mm from the end of the wall structure 1012 that begins with the primary bevel 1024. The slot 1034 is about 3 mm long. Advantageously, a sensor (shown in dotted lines) can be inserted into the farthest closed section of the wall structure 1012 through the slot 1034, thereby allowing it to be more easily delivered freely. It is expected that the size of the sensor to be inserted will depend at least in part on the size of the sensor to be inserted, corresponding to Figure 114 and 115The dimensions of the embodiments shown in the drawings may vary.

[0316] Figure 116 and 117 The needle is shown with a slot 1034 extending to the distal end of the needle 1010. In one embodiment, the proximal closed portion of the needle wall structure 1012 is approximately 8 mm, and the slot extends along the distal 6 mm of the wall structure. When viewed along the central axis, the slot 1034 forms a C-shape at the distal end of the needle.

[0317] Sensor delivery systems that utilize needles without slots are generally not capable of delivering pre-connected sensors (i.e., sensors that are connected to the sensor electronics prior to sensor insertion). With these systems, the electrical connection between the sensor and the sensor electronics occurs after the sensor has been inserted and often after the needle has been retracted. In some embodiments, for example Figure 116 and 117 In the embodiment illustrated in FIG, slot 1034 facilitates removal of the needle from a pre-connected sensor, which may be designed to be connected to the sensor electronics via wires that extend through the slot before and during sensor insertion. After sensor insertion, slot 1034 allows removal of the needle from sensor 1018 without disturbing the electrical connection established prior to insertion.

[0318] In short, a C-shape, V-shape, or other shape formed by a slot 1034 extending through the distal end of the needle 1010 can provide for delivery of a pre-connected sensor 1018. Wires from the sensor can extend through the slot 1034, while the remainder of the sensor remains within the opening 1022. More than one slot can be used, for example, for several electrical connectors. Additionally, the slots can vary in size, shape, and positioning depending on the desired use and / or reduction in invasiveness.

[0319] Windows and slots can be used with Figures 107 to 113 The bend and other characteristic combinations of the needles are shown in FIG.

[0320] Figure 130 and 131 Another embodiment of a needle 1010 is shown. Needle 1010 includes a single primary bevel 1024 with a 13-degree angle for bend 1030 from the lower horizontal wall line of wall structure 1012. The needle tip is elevated 0.152 (+ / - 0.051) mm from the bottom wall line of the wall structure. Needle 1010 has an inner diameter of 0.343 (+0.025 / -0.013) mm and an outer diameter of 0.457 (+0.025 / -0.013) mm. The primary bevel has a gentle curvature extending from its tip to the proximal edge. Figure 131A bevel length of 1.270 (+ / - 0.152) mm is shown. Cross-hatching shows a sandblasted (for burr removal and anti-coring) proximal length of 0.762 (+ / - 0.152) mm. Advantageously, reducing the bend angle from 17 degrees to 13 degrees reduces the chance of sensor damage during deployment.

[0321] Figure 132 Another embodiment of a single bevel needle 1010 is shown having a 13 degree bend 1030, but does not have a gentle curve in its bevel 1024. Instead, the primary bevel is straight and angled at approximately 13.5 degrees relative to the top outer edge of the wall structure 1012.

[0322] Figure 133 Another embodiment of a needle 1010 is shown having a single bevel 1024, comprising a 17 degree bend angle and a 7 degree bevel angle. The needle tip is elevated 0.012 inches from the bottom edge of the wall structure 1012.

[0323] Figure 134 Another embodiment of a needle 1010 is shown, in which the wall structure defines a proximal slot 1040. The proximal slot fans out into a portion of the needle on the side of the needle 1010 with the needle tip. The sensor 1018 includes a kink 1042 configured to rest in the proximal slot 1040 to maintain the sensor's orientation. Specifically, the proximal portion of the sensor dips downwardly into and optionally extends somewhat out of the proximal slot 1040, then reverses direction and continues distally into alignment with the needle's central opening 1022, which is opposite the proximal slot. Advantages of the proximal slot 1040 include retaining the sensor 1018 in a designated position until the push rod moves it out of position. Furthermore, maintaining the sensor 1018 in a desired or predictable position facilitates needle assembly. Another advantage is that by biasing the distal end of the sensor 1018 to the opposite side of the wall structure 1012, the bend 1030 of the needle 1010 can be cleared. The sensor 1018 will be less likely to run into the bend in the central opening 1022 during deployment.

[0324] Embodiments may incorporate various additional or alternative features to avoid or limit tissue trauma. For example, some embodiments may be configured to reduce vibration and / or lateral movement of the needle tip during the insertion and retraction phases of sensor deployment by decoupling at least a portion of the device from the needle. For example, some embodiments may include additional bearing features operatively coupled to the internal needle hub to decouple the internal needle hub from the external needle hub or other portions of the device and minimize the transmission of any vibrational forces to the needle. Additionally or alternatively, some embodiments may include features configured to counteract any torque placed on the needle during the insertion or retraction phases, or otherwise restrict or constrain the needle's path to a straight line during the insertion and retraction phases, thereby avoiding or reducing the potential for tissue trauma. In some embodiments, the needle hub itself may comprise a semi-rigid or slightly compliant material to provide attenuation of high-frequency vibrations and / or lateral movement during actuation and ensure that the needle follows a prescribed path. In some embodiments, the needle itself may comprise a relatively low temper (e.g., less than fully hard stainless steel) to allow the needle shaft to flex during the insertion and retraction phases.

[0325] Other aspects of systems and methods according to the principles of the present invention are now described. Figures 39 to 48 The diagram illustrates the steps of inserting a transmitter into a sensor housing according to a variation of the principles of the present invention. Figure 39 , illustrates a disposable housing 36 having the various components as described above, including the seal carrier 26 and the seal 24. In the figure, the seal carrier 26 is illustrated as part of a retraction step in the position it will be in immediately after removal of the cannula hub. Specifically, the seal carrier 26 is at approximately a 45° angle to the plane of the disposable housing 36. In many cases, the effects of gravity will overcome the frictional resistance of the hinge axis, causing the seal carrier 26 to rotate generally toward the disposable housing 36. However, in some cases it is unable to do so, and therefore the seal carrier remains at the 45° angle. This is generally a minor inconvenience as the user can easily push the seal carrier down into the disposable housing prior to attachment of the transmitter. See, e.g. Figure 40 , which depicts the transmitter 500 inserted into the disposable housing 36, and in particular wherein the tab 501 ( Figure 41 ) is inserted into the corresponding slot 442 ( Figure 40 ). The transmitter 500 then passes through the transmitter thumb pad 502 ( Figure 41 ) snaps into place by the user of the transmitter 500. In some embodiments, the snap fit between the transmitter 500 and the disposable housing 36 can be configured such that greater than about 2 pounds, greater than about 5 pounds, greater than about 10 pounds, or greater than about 20 pounds of force is required to remove the transmitter from the disposable housing 36 in order to prevent unwanted (or premature, in the case of a reusable transmitter) separation of the transmitter from the disposable housing.

[0326] If the seal carrier 26 is dropped into place in the disposable housing 36 after removal of the cannula hub, it is generally obvious to the user how the transmitter 500 will snap into place in the disposable housing. However, when the seal carrier 26 is retained at a large angle relative to the disposable housing 36, it is not always obvious to the user how the transmitter will snap into place in the disposable housing, especially if the angled position of the seal carrier blocks the user's view of the slot 442. Therefore, it is desirable to have a component for applying a force to rotate (or otherwise push) the seal carrier 26 downward into place in the disposable housing 36.

[0327] In some embodiments, as Figure 102 and 104 As shown in FIG, the transmitter 500a can include one or more keys 522a configured to engage with corresponding seats 524a in a corresponding disposable housing 36a. Figure 103 Another transmitter 500b is shown having a key 522b that has a different configuration than key 522a. The configuration of key 522b prevents transmitter 500b from resting in disposable housing 36a, such that transmitter 500b cannot be pressed, snapped, or otherwise installed in disposable housing 36a (e.g., as shown in FIG. Figure 40 Similarly, a seat (not shown) in the disposable housing configured to receive transmitter 500b can be configured to prevent transmitter 500a from resting in the disposable housing. Figure 104 A cross-sectional view of a transmitter 500a mounted in a compatible disposable housing 36a is shown, the cross-section being taken along surface A of the transmitter 500a (see FIG. Figure 102 By providing a corresponding key and socket for a corresponding transmitter / disposable housing combination that is incompatible with the key and socket of other combinations, a user can be prevented from installing the wrong transmitter (e.g., an incompatible transmitter) in the disposable housing. Figure 102 As shown in FIG, key 522a comprises a pair of protrusions extending from lower surface B of transmitter 500a. In other embodiments, a single protrusion or more than two protrusions are possible. Furthermore, while key 522a has a tapered configuration when extending in the direction of surface A, other key configurations are possible; for example, the key may taper in opposite directions or may have any other regular or irregular shape. In embodiments, one or more keys may extend from surface A in a direction orthogonal to surface A.

[0328] See now Figure 44 and 45, spring 38 can be coupled to the upper applicator housing 30, preloaded and biased against tab 504 on the seal carrier 26. It will be appreciated that in alternative embodiments, spring 38 can be replaced by other types of drive assemblies, and it can be coupled to other features of the applicator, so long as the feature remains stationary relative to the seal carrier 26. Moreover, spring 38 can be biased against other portions of the seal carrier, or even against the seal. Figure 42 Indicates the arrangement of the components when the cannula hub 32 is in place, and Figure 43 The arrangement of the components is indicated after retraction of the cannula hub 32. In the latter figure, the spring 38 applies a force in the direction of arrow 506 and since there is no longer a cannula hub positioned to resist this force, the seal carrier 26 will be urged downwardly into the disposable housing 36 by the spring 38.

[0329] See Figure 44 and 45 , the seal carrier 26 may be further provided with tabs 508 that engage and lock into corresponding slots 512 in the disposable housing 36 via a snap-fit ​​connection, thereby not allowing the seal carrier to move from the desired downward / flat position. Figure 45 A more detailed view of how this connection is formed is shown.

[0330] Return to view Figure 40 The disposable housing 36 is further configured to provide a single-use feature. This single-use feature prevents multiple reinsertion of the transmitter to protect the integrity of the seal, seal grease, and conductive bump, as well as the sensor position. It further prevents sensor restarts, i.e., reuse of the sensor for a second time, which is generally harmful and inconsistent with labeling. Additionally, the single-use feature can ensure that the transmitter 500 remains in place within the disposable housing 36 during removal of the combined transmitter / disposable housing / sensor ("wearable device") from the patient's body.

[0331] In more detail, the disposable housing 36 includes a rupturable section 432, which is attached to the remainder of the disposable housing 36 via frangible portions 436 and 438. In some embodiments, an access strip 434 can be employed to further facilitate removal of the rupturable section 432 from the remainder of the disposable housing 36. For example, a user can grasp, push, or pull the access strip 434 and twist or pull to remove the rupturable section 432 from the remainder. That is, the rupturable section 432 can be configured to bend or rupture apart, thereby removing the transmitter from the disposable housing once it has been removed from the body. In some embodiments, the rupturable section can be configured to detach from the remainder of the disposable housing 36 with a force between approximately 2 and 4 pounds. Furthermore, in some embodiments, the rupturable section can be configured to detach from the remainder of the disposable housing 36 at a rupture angle between approximately 30 and 60 degrees.

[0332] Figure 47 Illustrated is a system in which the rupturable section is being twisted as part of its removal process, after which the transmitter 500 can be removed and reused. Figure 47 Also illustrated is an adhesive portion 516 that attaches the wearable device to the user's skin.

[0333] The disposable housing 36 containing the rupturable section 432 comes with additional advantages. It allows for minimizing the insertion force required to latch the transmitter onto the disposable housing. This system minimizes deflection of the disposable housing due to compression of the seal. The system maintains the compression of the seal over time and temperature, thereby resisting harmful effects, including creep. The system provides a user-friendly removal process to separate the transmitter from the disposable housing after the wearable device has been removed from the body.

[0334] Return to view Figure 39 and 41 , the system may include a one-way double buckle feature configured to make it generally impossible to remove the transmitter while on the body. (This aspect is also discussed in Figure 48 514, where the flush nature of the transmitter 500 relative to the disposable housing 36 becomes apparent.) The dual snaps may be located on the sidewalls of the disposable housing and are embodied in part by cavities 519 defined in the disposable housing 36 that cooperate with tabs 514 on the transmitter 500. Specifically, the tabs 514 snap into the cavities 519 during insertion of the transmitter. The sidewall snaps also help minimize deflection and maintain seal compression.

[0335] As described above, many of the embodiments described provide ways to make additional power and force available to perform the steps of inserting or retracting. In some cases, the additional force does not result in an increase in overall force, but rather results in a better force distribution so that force is available when needed to perform the required steps. In some cases, and as described below, systems and methods according to the principles of the present invention involve ways to reduce the required force, for example, to reduce the force required in a given force distribution. Many of the systems and methods described below achieve this effect by modifications to the seal assembly 24 generally discussed above and modifications to its associated seal carrier 26. Additionally, in addition to relaxing the force requirements for inserting and retracting the assembly, systems and methods according to the principles of the present invention also involve reducing the effect of the seal slingshot as described above, also by modifications to the seal 24 and / or by other means of preventing movement of the sensor wire.

[0336] Specifically, Figures 49 and 51 to 56 describe a method of reducing the slingshot. Figures 73 to 77 Describes a way to hold a sensor (e.g., sensor wire) more stably or in a stronger form, which also counteracts the slingshot, and Figure 50 , 57 to 72 and 78 to 83 describe ways of separating a seal from an insertion assembly (e.g., from a cannula) in order to reduce the force required to remove the cannula.

[0337] In more detail, Figures 49A to C One approach to modifying a seal to reduce or eliminate seal slingshot is described. In this figure, a seal 624, for example an elastomeric seal such as a silicone seal, is overmolded onto a seal carrier 626, where the overmolding includes bonding between the elastomeric seal 624 and the seal carrier 626, which can be constructed of, for example, a hard, rigid polycarbonate material. While overmolding is discussed here, it will be understood that other methods of adhesion, including the use of glue, can also be employed.

[0338] In this embodiment, various ribs can be provided to reduce seal deformation during cannula removal. Ribs can be attached to the seal during the overmolding process to even more completely position the seal in place. One or more columnar ribs 602 at least partially surround the conductive puck (not shown). The columnar ribs 602 can completely surround the puck or can only partially surround the puck. In some configurations, sidewall ribs can also be provided to reduce seal deformation during cannula removal. Continuous wall ribs 604 are illustrated, which, for example, extend from one side of the seal carrier to the other along the distal / proximal axis. The ribs as described can be formed of a material similar or identical to the seal carrier 626 and can be integral therewith. The ribs can also be formed of different materials, but generally the material should have a durometer hardness higher than that of the seal 624. Additional ribs 606 are shown and may be “floating” ribs, located within the seal 624 but not directly connected to the seal carrier 626 , or the additional ribs 606 may be directly connected to the seal carrier 626 .

[0339] It will also be understood that variations in these configurations of the ribs can help reduce seal slingshot, for example by inhibiting movement of the seal in and along the distal / proximal axis. Certain of these configurations are described below. For example, to even further reduce the effect or likelihood of seal slingshot, a cavity 608 can be defined in the seal 624 to reduce the amount of seal material that comes into contact with the cannula, thereby reducing the effect of seal slingshot.

[0340] Another way to relax the force requirements for insertion and retraction is to Figure 50 A description is provided, which illustrates a system designed to reduce the force required to remove an inserted component, such as a cannula. In the figure, a conductive puck 123' is illustrated having a cored section 518, which is cored in the same manner as a pineapple is cored before slicing. The cannula 78 is also illustrated, but the seal surrounding the conductive puck 123' and the remainder of the seal carrier assembly are omitted for clarity. By coring the conductive puck, frictional resistance is reduced when the cannula is retracted from the puck. Resistance from the seal may still exist, but it can also be reduced as described below. Coring allows for a minimum wall thickness to remain in the cylindrical wall, for example, at least approximately 0.030", to allow for compression on the puck and prevent buckling. The shape can be generally cylindrical to prevent the need to key the puck during assembly, but other shapes are possible. For example, square, hexagonal, or hourglass shapes, but these may be less preferred due to increased assembly difficulty.

[0341] Figures 51 to 56Another embodiment 628 of a seal for use in a seal carrier is shown, this embodiment being referred to as a hybrid seal. A hybrid seal embodiment can utilize different materials having different durometer hardnesses. A rigid or high durometer material can be utilized for sensor placement, thereby reducing slingshot, and a softer or lower durometer seal material can be utilized for increased sealing capabilities. Figures 51 to 56 In one embodiment, a hybrid dual-material design is employed that provides the properties of a high-durometer material, such as silicone, necessary for sensor placement, but with a different, softer material strategically placed for sensor wire sealing. This embodiment addresses certain issues that arise when the seal material is a single, single type, particularly materials like silicone. Silicone has properties that are favorable and result in accurate sensor placement relative to the puck in the applicator device. However, as mentioned, the same properties that facilitate accurate sensor placement can sometimes make sealing around the sensor wire more difficult.

[0342] In more detail, a first material 634, which can be a high durometer material such as an elastomer (e.g., silicone), can be placed in locations that make significant contact with the cannula, needle, and sensor wires. A second, lower durometer material 632 can then be placed to form the remainder of the seal 628 and, specifically, in locations where sealing functionality is desired. The second material 632 can be, for example, a thermoplastic elastomer (TPE). As described, the second material 632 typically has a lower durometer hardness than silicone, allowing it to achieve a better seal.

[0343] Figures 51 to 56 The embodiment of provides a unique solution for at least sterilization reasons. TPE is generally more robust to sterilization effects than silicone (e.g., to gamma rays and electron beams), and thus the hybrid seal 628 provides significant advantages over non-hybrid seals.

[0344] Figures 57 to 59 illustrate another embodiment of a seal according to the principles of the present invention, referred to as a flow seal 636. Specifically, as described above during application deployment, the force required to remove the cannula from the seal creates stress within the assembly and increases risk due to the preloaded and stressed assembly, especially in long shelf life situations. The embodiment of Figures 57 to 59 addresses this issue by significantly reducing the force required to remove the cannula from the seal. It solves this problem by removing a significant portion of the seal from the seal carrier and replacing it with a flowable material.

[0345] Specifically, cannula 78 passes through a channel 646 formed between sealing portion 638 and seal carrier 644. During manufacturing, a fluid, such as grease (e.g., petroleum jelly), is injected into channel 646. Once injected, it need not occupy the entire channel. However, when the launcher is placed on top of the seal and forced onto the seal and seal carrier, making contact with knobs 123 and 125, sealing portion 638 will be significantly compressed, forcing the grease through the channel. The grease provides a moisture barrier and significantly reduces the retraction force required for the cannula, thereby reducing slingshot.

[0346] Grease can be inserted through the diaphragm 642, for example, with a needle. A front diaphragm 648 can be provided and can advantageously be used to help hold the sensor wire in place via friction. The diaphragm 648 (and diaphragm 642) can be made of a seal material (e.g., an elastomer) and are generally prestressed to "close" when the cannula or needle is removed. In some embodiments, the diaphragm can be made of a more rigid elastomer to allow for a more rigid hold on the wire. For this reason, there may still be an increase in the force required when the cannula begins to retract from the diaphragm, but in many applicator embodiments, the start of cannula retraction is at a point when the retraction driver (e.g., a spring) has considerable energy to apply the force, e.g., the spring is not at the end of its travel, and therefore easily performs this retraction.

[0347] The knobs 123 and 125 can "float" in the sense that they are held by the sealing portion 638 and are not penetrated by the cannula (nor by the sealing portion 638) except at the septum 648. However, the knobs 123 and 125 can be retained within the sealing portion 638 by the use of annular tabs 652 that move within cylindrical channels 654.

[0348] Figures 57A to 57C Illustration of the needle and grease before insertion ( Figure 57A ), the needle has been inserted but before grease is injected ( Figure 57B ) and finally after grease injection ( Figure 57C ) sealing portion 638. Figure 59 A perspective view indicating the flow seal 636 in place within the seal carrier 644 .

[0349] The embodiments of Figures 57 to 59 offer various advantages. For example, when the transmitter is forced onto the disposable housing and seal / seal carrier, grease flows through the interior of the seal carrier, significantly protecting the wires from moisture. Another significant advantage is achieved in the embodiments of Figures 57 to 59, particularly compared to using a completely solid seal. Specifically, the elastomeric seal can become "cured" during the sterilization process. Therefore, when the seal is manufactured and sterilized with the cannula in place, removal of the cannula can sometimes leave a void. In current systems, grease or petroleum jelly can provide a gap-filling function. Another significant advantage is achieved in the function of the flow seal on the applicator mechanism. For example, the flow seal can reduce the force required to retract the seal, eliminating the need for a booster spring or other "extra" retraction force mechanism.

[0350] Alternatives to the systems of Figures 57 to 59 will also be appreciated. For example, while Figure 57 shows only a single wire-retaining septum, septum 648, another septum could be placed on the other side of the seal, creating a dual-septum system that would serve to trap grease between the two septa. Additionally, the septum serves the additional purpose of removing grease from the cannula so that it remains within the sealing area.

[0351] In another alternative, the cannula can be held just proximal to the septum, rather than piercing it. During deployment, i.e., needle insertion, the needle pierces the septum and sensor insertion is performed. The cannula still serves the purpose of preventing the needle from coming into contact with the grease inside the flow seal. This embodiment has the benefit of maintaining the septum in a stress-free state during sterilization and storage. This aspect eliminates compression settings that would otherwise reduce the septum's retention of the sensor after sterilization and storage.

[0352] In yet another embodiment, Figures 60 to 62 As shown in FIG, seal 662 can be constructed with a plurality of rings or annular seals 664, such as a face seal having one or more concentric annular protrusions or ridges on the sealing face. Embodiments employing multiple rings can provide multiple sealing barriers against intrusion and can also focus sealing forces on more critical areas of the seal. In some embodiments, one or more O-rings can be positioned adjacent to one or more of the annular protrusions (e.g., in a groove between two ridges) to create an additional seal. As with the previous embodiment, the top of the annular seal contacts the emitter and the bottom contacts the seal carrier.

[0353] This embodiment can reduce the amount of force required to remove the cannula from the seal. In addition, it allows, for example, a seal rupture to occur in one ring without affecting the sealing integrity of the other rings. (Seal rupture can occur due to surface imperfections, tolerances, and the like.) Figures 60 to 62In variations of the embodiments, the number of rings may vary, their cross-sectional shapes may vary, and the shapes of the rings themselves may vary, for example, non-circular rings may be employed in some embodiments.

[0354] Another embodiment that can be used to reduce the normal force of the seal on the cannula and thus make the cannula easier to remove is to use a sandwich seal. Figures 63 to 69 This sandwich seal is illustrated.

[0355] In particular, as described, the force required to remove the cannula from the seal often stresses the seal and components of the applicator system. Efforts have been made to reduce the force required to remove the cannula by slitting the seal, but this seal slitting operation is often undesirable and harmful.

[0356] The sandwich seal utilizes a two-part design, with the cannula sandwiched between the two parts. This results in generally much lower cannula pull force requirements, as the seal exerts less friction on the cannula along its length. Other advantages include eliminating the need for grease for sealing, and the sensor remains decoupled from the seal, making it much more robust. Ideal sealing materials, such as low-durometer elastomers, can be used because the sealing function is decoupled from other functions, such as sensor placement.

[0357] More specifically, a sandwich seal can be used that increases the gap between the seal and the cannula. Instead of a single block of elastomeric material, two blocks can be used, and the cannula can pass through the middle of the blocks. The cannula thus has a larger opening to pass through, minimizing drag and slingshot.

[0358] First see Figure 63 , a seal carrier 668 is shown having a bottom sandwich seal assembly 672. A passage 674 having a generally "U" shape is seen passing through cylindrical posts 676. A round block (not shown) may be placed between each set of cylindrical posts. The seal carrier 668 may be made of a rigid material such as polycarbonate, and the bottom sandwich seal assembly 672 may be made of an elastomer or other material such as silicone, or any material that allows for sensor retention.

[0359] The top sandwich assembly 678 is shown having a top frame 682 and a top seal 684. The top sandwich assembly 678 can be hingedly connected to the bottom sandwich seal assembly 672 (see FIG. Figure 64 ), and the top sandwich assembly can then be quickly retained to the bottom sandwich seal assembly 672 by the latch tab 686, which can pass through and quickly retain to the tab 688 in the bottom assembly.

[0360] In use, and during insertion, the system may be in an unlatched position, e.g. Figure 64. Any of the applicators described above can be used to deploy the sensor wire between the top seal 684 and the bottom sandwich seal assembly 672. The top and bottom seals (as well as the top frame and seal carrier) can then snap together using latch tabs 686 and 688. The top and bottom seals can snap together when the transmitter is inserted, providing the desired seal and sensor retention. A knob can be included in the top seal and can again snap down over the sensor wire when the transmitter is inserted.

[0361] In one embodiment, the bottom sandwich seal assembly 672 can have a higher durometer hardness than the material of the top seal 684. In another embodiment, the opposite may be true. The bottom sandwich seal assembly 672, having a higher durometer hardness, allows the sensor wires to be supported in a manner that creates a reliable connection to the dome, but also allows for a good seal when clipped to the lower durometer material snapped down from above. In some cases, both the frame 682 and the top seal 684 can be made of an overmolded low durometer seal material.

[0362] Figures 63 to 65 Variations of the embodiment may include one or more of the following. A diaphragm may be placed at the distal end of the seal, such as within the top frame 682, and may be pre-punctured by a needle. After deployment, the sensor wires may be retained by the diaphragm. In another variation, the bottom housing may include a puck retention feature that prevents the wires from moving out of the puck conductive path and provides increased stability to the puck.

[0363] In yet another variation, the top portion of the seal (top frame 682 and top seal 684) can remain above the needle, and the septum (described above) is not pierced in its manufactured state. Instead, the needle pierces the septum after activation of the applicator. In this variation, the cannula can be eliminated, thereby reducing parts and increasing manufacturability. The septum is beneficially maintained in a stress-free state during sterilization and storage. The advantage of this aspect is that the limited compression setting that would otherwise reduce the retention of the septum on the sensor after sterilization and storage. In this variation, the top portion of the seal can be kept out of the path of the needle before and during deployment and during storage, which can be achieved by placing a buckle on the top seal assembly or incorporating features into the carrier that hold the seal in the applicator and prevent the top seal from compressing on the needle.

[0364] Figure 66A specific embodiment of a sandwich seal 694 is shown, showing a low durometer seal 684' material held in a top frame 682, which is hingedly attached to the seal carrier 668. In this embodiment, a diaphragm 696 is positioned, wherein the diaphragm material has a relatively high durometer hardness, such as silicone having a durometer hardness of 50 to 70 Shore A, such as having an exemplary thickness of, for example, 0.062". Unlike Figures 63 to 65 implementation plan, in Figure 66 In the embodiment of the present invention, the lower durometer seal material from the top seal 684 is not in the path of the cannula. Instead, the high durometer silicone of the septum provides retention for the sensor wire to prevent it from being removed before the seal is fully snapped down. As before, after insertion of the transmitter, the seal can be snapped down to the final configuration. Even before reaching this final configuration, the sensor wire is still firmly held in place by the septum to reduce the chance of accidental removal of the sensor wire before the transmitter is snapped down.

[0365] Figures 67 to 69 The progressive steps for using the sandwich seal 694 with the diaphragm are illustrated. Figure 67 shows a profile view of the sandwich seal in an open position, and Figure 68 A side view is shown. Figure 67 A side view is shown in the closed position.

[0366] Figures 63 to 69 Advantages of embodiments of the present invention may include one or more of the following. In some embodiments, the cannula can be removed from the design. Embodiments can significantly reduce or eliminate the slingshot effect of retraction. The top or bottom portion of the seal design, or both, can be overmolded. Embodiments allow for improved product manufacturability and reliability. For example, the cutting and swapping process required in a single piece seal can be eliminated in these embodiments. In some embodiments, additional force devices such as booster springs can be eliminated because the force that the cannula or needle has to retract has been reduced.

[0367] Figures 70 to 72 Another embodiment of a seal design 702 is illustrated, specifically showing a "stacked" seal. Similar to a sandwich seal, this embodiment applies less normal force to the cannula, resulting in a lower cannula retraction force requirement. The sensor remains decoupled and can be much more robust, as this can be achieved with a diaphragm. Figure 70 The embodiment does not require grease for sealing and can use ideal sealing materials, such as low durometer hardness TPE, because the sealing function is decoupled from other functions such as sensor placement. In addition, the undesirable seal cutting process is no longer required.

[0368] In an embodiment according to these principles, the seal housing 704 contains a diaphragm 705 as described above for holding the sensor wire, located at the distal portion of the seal subassembly. Material 706 is shown overmolded onto the rigid plastic component 703. Material 706 can be a low durometer component such as TPE or silicone or other sealing material. Material 706 also contacts the bottom portion of the rigid plastic component 703, as shown. Figure 71 The blocks 708 and 710 are shown together with the cannula 712 in the figure. Figure 70 The implementation scheme has Figure 63 Some similarities between sandwich seals, one difference is Figure 70 An embodiment includes an overmolded top sealing material rather than a sealing material that is mechanically inserted into the frame.

[0369] Figures 73 to 77 Other ways to counteract the slingshot and ensure accurate sensor placement are shown. Figure 73 and 74 , the seal carrier 732 can have a base 734 and a top portion 736, which can be according to any of the described embodiments. Either or both (the base portion is shown) can incorporate a spring element 738, which, for example, engages an element 742 integral with the base 734 and is held in place thereby. The spring element 738 includes a contact element 744, which engages the cannula 746 and provides pressure against it prior to removal of the cannula. Figure 73 A seal carrier having one spring element 738 is shown. Figure 74 A seal carrier 732' is shown incorporating two spring elements. Whether one or two spring elements are used, the operation is the same.

[0370] When the cannula is removed during retraction, the spring element 738, and in particular the contact element 744, no longer engages the cannula but engages the sensor wire, thereby providing additional force against movement of the sensor wire. In one variation, the spring element 738 can be configured to provide a greater force when in contact with the sensor wire than when in contact with the cannula. In another variation, the spring element 738 can be prevented from moving so that the contact element 744 does not even engage the cannula until, for example, the cannula is removed, and then the prevention of movement can be removed, causing the spring element to contact and provide force against the sensor wire.

[0371] Figure 75Another embodiment of a spring element system is shown, in which a spring element 739 has a first portion 740 and a second portion 745, and these portions are arranged on opposite sides of a seal carrier 737. By being located on opposite sides of the seal carrier 737, the spring element 739 can be firmly engaged with the seal carrier 737 by friction and by spring force. The second portion 745 can include, for example, two fingers 741 and 743, which are held apart by the cannula or an element through which the cannula passes. After the cannula is removed, or after the element through which the cannula passes is removed, the two fingers 741 and 743 close down onto the sensor wire and securely hold the sensor wire.

[0372] Figure 76 An alternative embodiment is shown in which, instead of the cannula or sensor wire being held securely by a spring element, the seal is held against the slingshot by a spring element. Specifically, a seal carrier 754 is shown with a seal 756, Figure 76 is shown in cross-section in FIG. A cannula 762 is shown through which the needle and sensor wire can be delivered as described above. A spring element 754 is employed to securely hold the seal 756, and in particular to resist movement such as by a slingshot. In this way, the seal is prevented from moving during cannula removal, thereby reducing the effect of the slingshot on the sensor wire.

[0373] Figure 77 An assembly 772 is illustrated that operates in a manner similar to a mousetrap. In this embodiment, a spring element 773 provides a force on the distal side of the seal that is generally perpendicular to the direction of cannula retraction.

[0374] Figures 78 to 83 Further illustrated is the manner in which the cannula is removed and the sensor wire is placed within the elastomeric seal in accordance with the principles of the present invention. As described, friction between the seal and the cannula can cause the elastomeric seal to move, and this movement can cause undesirable side effects, such as sensor placement errors due to slingshotting.

[0375] Figure 78 Embodiments such as those described herein provide a means of reducing the amount of seal interaction with the sensor wires by creating cavities along the sensor path. Additionally, anchoring features are provided to limit the amount of seal movement. For example, a solid wall can be employed within the sensor housing to limit the amount of sensor movement, and / or glue can be employed to further limit seal movement. Furthermore, certain embodiments described herein provide for a reduction in the force required to remove the cannula.

[0376] For more details, see first Figures 78 to 79, shows a design for a seal assembly 802 having a seal housing, wherein an undercut is created through the puck hole to create a cavity in the cannula / wire path. Cavity 804 is shown adjacent to puck hole 808a (for the distal puck hole), and cavity 806 is shown adjacent to puck hole 808b (for the proximal puck hole). In both cases, the undercut below the top of the puck hole is positioned to create the cavity. In the illustrated embodiment, material is removed around both sides of the distal puck, while for the proximal puck, only material is removed up to the puck support wall. An insert 810 for the distal portion of the seal is shown, allowing it to be inserted from the front of the seal carrier. Insert 810 serves the following purposes: to expose the tip of the cannula (so that no seal is pierced by a moving needle) and to limit the wall thickness of the seal material between cavity 804 and insert 810.

[0377] Figures 80 to 81 Another embodiment is shown in the figure, where glue wells are added on the front and back. Glue is added through the openings to attach the elastomer to the rigid seal carrier. This example further illustrates the Figures 78 to 79 Same cavity and insert as shown in .

[0378] In more detail, the seal housing 812 includes one or more glue wells 814. Figure 80 , four glue wells 814 are shown, two on the front and two on the back of the seal assembly. A seal 816 is also shown, and further reference is made to Figure 81 It can be seen how a glue well 814 is formed in the seal 816. The glue well can be chamfered and rounded. The glue well can extend to the bottom layer of the seal carrier, and once the glue has been placed in the glue well, the seal is adhesively coupled to the seal housing, thereby reducing seal movement and subsequent slingshot.

[0379] Figures 82 to 83 Another embodiment is illustrated in which material is removed along the sensor line and cannula path, again by creating a shaped cavity formed from the top surface. In embodiment 818, a front seal cavity 820 is formed or defined which may have, for example, an oval shape of the seal material removed. The dome support is still maintained. This cavity has no undercuts and thus simplifies the corresponding manufacturing tooling. Also shown is an intermediate seal cavity 822 which again may have an oval shape of the material removed, but in this cavity as well as the front seal cavity, non-oval shapes may also be removed. The dome support is again maintained and similar to the front seal cavity, the intermediate seal cavity has no undercuts, thereby simplifying the manufacturing tooling. As Figures 78 to 79 In some embodiments, the distal seal can be inserted from the front of the seal carrier.

[0380] will understand that in Figure 78In any of the embodiments of the present invention, variations in the placement and shape of the cavities and glue wells are possible and depend on the specific seal assembly design, as well as the sensor wire and / or cannula placement and the desired removal force distribution.

[0381] Variations of the above will also be appreciated. For example, in some cases, a user may find it difficult or inconvenient to hold the applicator flat on their skin while simultaneously pushing the activation button. This is particularly true if the user inserts the sensor on their side or rear. For these reasons, and referring to Figure 84 The applicator 902 can be automatically triggered by a remote activation device 906 by causing the electromechanical device 904 to activate a trigger. Although the receiver 904 is shown in the figure as occupying the position of a button, it will be understood that it can be completely internal to the applicator 902.

[0382] The activating device 906 and the activated device 902 (i.e., the applicator) can be communicatively coupled in many ways, including wirelessly or via a wired link. The wireless communication scheme can include, for example, an RF link that can be implemented through the Bluetooth protocol, WiFi, or the like. Other communication schemes will also be understood. The advantages of these systems and methods according to the principles of the present invention are described above, but also include that the user can position the applicator on their body in a more stable manner, rather than having to use one of their fingers to push the activation button (or manipulate another activator, such as a slider or the like disclosed herein).

[0383] The activation device 906 can be, for example, a smart phone, a smart watch, a computing device, a dedicated receiver or transmitter, such as a garage door opener or other remote control, or the like. It can also incorporate a timer or other time delay device. In an alternative embodiment, a button on the applicator can be used, such as Figures 3 to 16 However, a time delay may be used.

[0384] In another variation, see Figure 85 , shows an embodiment in which a transition zone is provided at the intersection of the adhesive portion 516 and the disposable housing 36. Specifically, a transition zone comprising a volumetric solid 910 is provided to facilitate the transition between the adhesive portion 516 and the disposable housing 36. The transition zone can comprise a material such as silicone, which can be formed and can provide a contoured transition between the adhesive patch and the transmitter housing on the wearable device. The transition zone limits the occurrence of features on the wearable device that could snag on elements (e.g., the user's clothing) and tear off the wearable device. The material can be flexible for patient comfort.

[0385] In another embodiment, and referring to Figure 105 and 106 , applicator device ( Figure 105The disposable housing 36d may be adapted for use when the disposable housing 36d is applied to the patient's skin. The disposable housing 36d may be positioned over the adhesive patch 90d. The disposable housing 36d may be configured to receive a transmitter 500d adapted for single use (see FIG. Figure 106 ). The disposable housing 36d may include a slot 442d configured to receive a corresponding tab on the transmitter 500d ( Figure 106 Not shown, but similar to Figure 41 501) to help position the transmitter 500d when installing the transmitter in the disposable housing 36d in a similar manner to the transmitter 500 and the disposable housing 36.

[0386] -A1; US Figure 40 However, Figure 40 In contrast to the transmitter 500 and disposable housing 36 shown in FIG, the disposable housing 36d and transmitter 500d can be configured without any rupturable features, release tabs, or snaps, or other release features designed to facilitate removal of the transmitter 500d after installation in the disposable housing 36d. Thus, some embodiments may include a single-use disposable housing configured for use with a single-use transmitter. In some embodiments, such a disposable housing can be configured to occupy a smaller area than a disposable housing configured with a rupturable portion or other release features designed to facilitate removal of a reusable transmitter.

[0387] In an embodiment, the sensor insertion device may generally include, for example, an upper housing, a lower housing, a protective tab (e.g., a safety frangible), a trigger button, a torsion spring housing or cam, a torsion spring, an outer needle hub, an inner needle hub, a needle, a sensor, a push rod hub, a push rod, a cannula hub, a cannula, a compression spring, a seal carrier, a seal, a disposable housing, and an adhesive patch as described herein. In some embodiments, the sensor insertion device may be configured to be generally deployed as follows. In an initial configuration, for example, when manufactured and provided to a consumer, the upper housing and the lower housing are coupled together to accommodate the internal components of the device. The torsion spring and the compression spring are pre-energized or preloaded. The outer needle hub, the inner needle hub, the cannula hub, and the push rod hub are fixedly coupled to each other in an initial pre-deployment configuration, with the needle and push rod in an initial proximal position. The cannula is in an initial distal position and is operatively coupled to the disposable housing via a seal. In some embodiments, the cannula extends through the elastomeric seal in frictional engagement with the elastomeric seal. The seal carrier is hingedly coupled to the disposable housing but positioned at an angle relative to the disposable housing that matches the insertion angle. In the initial configuration, the cannula hub cooperates with the ribs of the lower housing to secure the seal carrier in this angled position. Furthermore, in the initial configuration, the tabs or other protrusions of the trigger are positioned to block or prevent rotation of the torsion spring housing and thereby prevent activation of the torsion spring. The sensor is positioned completely within the lumen of the needle at the distal end of the push rod. The push rod, needle, and cannula are arranged in a telescopic manner along the insertion axis of the sensor.

[0388] To deploy the device, the user first decouples or otherwise removes a protective tab that was initially coupled to the trigger to prevent inadvertent deployment of the device. The user then depresses the trigger. The trigger slides through a track in the upper housing, and the tab is displaced from its blocking engagement with the torsion spring housing, thereby releasing or activating the torsion spring and causing the torsion spring housing to rotate about its central axis.

[0389] The torsion spring housing includes a pin that is configured to engage with a slot or yoke in the outer needle hub. When the torsion spring housing begins to rotate (under the force of the activated torsion spring), the pin pushes the slot in the distal direction and, therefore, the outer needle hub. Since the inner needle hub and the push rod hub are both fixed to the outer needle hub at this stage, but the cannula hub is fixed in the distal direction (for example, prevented from moving distally by the positioning of the seal carrier and the disposable housing), the inner needle hub and the push rod hub both move distally relative to the cannula hub. By this movement, the inner needle hub moves from a first engagement position with the cannula hub to a second engagement position with the cannula hub. The needle, sensor, and push rod together advance to their most distal position, and the needle and sensor are inserted into the skin.

[0390] After (or simultaneously with) the outer needle hub, the inner needle hub, and the pusher hub reach their distal-most positions, an arm or other feature of the pusher hub engages a corresponding tab or other position-engaging feature of the lower housing to lock the pusher hub in its distal position (e.g., to prevent proximal movement of the pusher hub). A return spring feature forming part of (or coupled to) the pusher hub deforms when the pusher hub reaches its distal position to bias the pusher hub against the position-engaging feature of the lower housing, thereby fixing the position of the pusher hub (and pusher) in the axial direction.

[0391] As the torsion spring housing continues to rotate (still under the force of the activated torsion spring), the drive mechanism reverses itself and the engagement of the pin with the slot begins to move the outer needle hub back in the proximal direction, thereby initiating needle retraction. Because the pusher hub is fixed in the distal position at this stage (e.g., prevented from proximal movement by its engagement with the lower housing), the pusher provides a backstop for the sensor in the distal position and prevents proximal movement of the sensor when the needle moves in the proximal direction.

[0392] Movement of the outer needle hub in the proximal direction causes the outer needle hub to decouple from the push rod hub (e.g., by causing features of the outer needle hub and the push rod hub to disengage or interengage). As the outer needle hub continues to move proximally relative to the push rod hub, a tab or protrusion of the push rod hub engages with a tab or protrusion of the inner needle hub, releasing the inner needle hub from engagement with the outer needle hub. At or approximately the same time, the torsion spring housing rotates into a section of the upper housing containing one or more engaging ratchet teeth and a hard stop. This structure engages the ratchet arm of the torsion spring housing and prevents rotational movement of the torsion spring housing, as well as linear movement of the outer needle hub. Decoupling of the inner needle hub from the outer needle hub serves to release or otherwise activate the compression spring, which further drives the inner needle hub in the proximal direction. As the inner needle hub is driven proximally, it couples with a second engagement feature of the cannula hub. Movement of the inner needle hub pulls the needle, cannula hub, and cannula in the proximal direction. This drives the cannula out of the seal and drives the cannula and needle to the fully retracted proximal position.

[0393] Once the cannula hub is removed from beneath the seal carrier to a proximal position, the seal carrier is free to rotate about its hinged coupling with the disposable housing from its initial angled orientation to a flat or other final orientation within the disposable housing, in which the disposable housing can receive the transmitter. In some embodiments, this rotation is aided by, for example, the addition of a spring-like arm biased against the seal carrier. At this stage, the disposable housing is also decoupled from the rest of the device, allowing the device to be lifted by the user, leaving the disposable housing applied to the skin and ready to receive the transmitter.

[0394] It should be understood that all methods and processes disclosed herein can be used in any continuous or intermittent glucose monitoring system. It should further be understood that the embodiments and / or execution of all methods and processes can be performed by any suitable device or system, whether local or remote. In addition, any combination of devices or systems can be used to implement the methods and processes of the present invention.

[0395] Methods and apparatus suitable for use in conjunction with aspects of the preferred embodiments are disclosed in the following patents: U.S. Patent No. 4,757,022; U.S. Patent No. 4,994,167; U.S. Patent No. 6,001,067; U.S. Patent No. 6,558,321; U.S. Patent No. 6,702,857; U.S. Patent No. 6,741,877; U.S. Patent No. 6,862,465; U.S. Patent No. 6,931,327; U.S. Patent No. 7,074,307; U.S. Patent No. 7,081,195; U.S. Patent No. 7,108,778; U.S. Patent No. 7,110,803; U.S. Patent No. 7,134,999; U.S. Patent No. 7,136,68 9; U.S. Patent No. 7,192,450; U.S. Patent No. 7,226,978; U.S. Patent No. 7,276,029; U.S. Patent No. 7,310,544; U.S. Patent No. 7,364,592; U.S. Patent No. 7,366,556; U.S. Patent No. 7,379,765; U.S. Patent No. 7,424,318; U.S. Patent No. 7,460,898; U.S. Patent No. 7,467,003; U.S. Patent No. 7,471,972; U.S. Patent No. 7,494,465; U.S. Patent No. 7,497,827; U.S. Patent No. 7,519,408; U.S. Patent No. 7,583,990; U.S. Patent No. 7,591,801; U.S. Patent No. 7,599,726; U.S. Patent No. 7,613,491; U.S. Patent No. 7,615,007; U.S. Patent No. 7,632,228; U.S. Patent No. 7,637,868; U.S. Patent No. 7,640,048; U.S. Patent No. 7,651,596; U.S. Patent No. 7,654,956; U.S. Patent No. 7,657,297; U.S. Patent No. 7,711,402; U.S. Patent No. 7,713,574; U.S. Patent No. 7,715,893; U.S. Patent No. 7,761,130; U.S. Patent No. 7,771,352; U.S. Patent No. 7,774,1 U.S. Patent No. 45; U.S. Patent No. 7,775,975; U.S. Patent No. 7,778,680; U.S. Patent No. 7,783,333; U.S. Patent No. 7,792,562; U.S. Patent No. 7,797,028; U.S. Patent No. 7,826,981; U.S. Patent No. 7,828,728; U.S. Patent No. 7,831,287; U.S. Patent No. 7,835,777; U.S. Patent No. 7,857,760; U.S. Patent No. 7,860,545; U.S. Patent No. 7,875,293; U.S. Patent No. 7,881,763; U.S. Patent No. 7,885,697; U.S. Patent No. 7,896,809;U.S. Patent No. 7,899,511; U.S. Patent No. 7,901,354; U.S. Patent No. 7,905,833; U.S. Patent No. 7,914,450; U.S. Patent No. 7,917,186; U.S. Patent No. 7,920,906; U.S. Patent No. 7,925,321; U.S. Patent No. 7,927,274; U.S. Patent No. 7,933,639; U.S. Patent No. 7,935,057; U.S. Patent No. 7,946,984; U.S. Patent No. 7,949,381; U.S. Patent No. 7,955,261; U.S. Patent No. 7,959,569; U.S. Patent No. 7,970,448; U.S. Patent No. 7,974,6 U.S. Patent No. 72; U.S. Patent No. 7,976,492; U.S. Patent No. 7,979,104; U.S. Patent No. 7,986,986; U.S. Patent No. 7,998,071; U.S. Patent No. 8,000,901; U.S. Patent No. 8,005,524; U.S. Patent No. 8,005,525; U.S. Patent No. 8,010,174; U.S. Patent No. 8,027,708; U.S. Patent No. 8,050,731; U.S. Patent No. 8,052,601; U.S. Patent No. 8,053,018; U.S. Patent No. 8,060,173; U.S. Patent No. 8,060,174; U.S. Patent No. 8,064,977; U.S. Patents 8,073,519; 8,073,520; 8,118,877; 8,128,562; 8,133,178; 8,150,488; 8,155,723; 8,160,669; 8,160,671; 8,167,801; 8,170,803; 8,195,265; 8,206,297; 8,216,139; 8,229,534; 8,229,5 U.S. Patent No. 35; U.S. Patent No. 8,229,536; U.S. Patent No. 8,231,531; U.S. Patent No. 8,233,958; U.S. Patent No. 8,233,959; U.S. Patent No. 8,249,684; U.S. Patent No. 8,251,906; U.S. Patent No. 8,255,030; U.S. Patent No. 8,255,032; U.S. Patent No. 8,255,033; U.S. Patent No. 8,257,259; U.S. Patent No. 8,260,393; U.S. Patent No. 8,265,725; U.S. Patent No. 8,275,437; U.S. Patent No. 8,275,438; U.S. Patent No. 8,277,713;U.S. Patents 8,280,475; 8,282,549; 8,282,550; 8,285,354; 8,287,453; 8,290,559; 8,290,560; 8,290,561; 8,290,562; 8,292,810; 8,298,142; 8,311,749; 8,313,43 4; U.S. Patent No. 8,321,149; U.S. Patent No. 8,332,008; U.S. Patent No. 8,346,338; U.S. Patent No. 8,364,229; U.S. Patent No. 8,369,919; U.S. Patent No. 8,374,667; U.S. Patent No. 8,386,004; U.S. Patent No. 8,394,021; U.S. Patent No. 8,527,025; U.S. Patent No. 7,896,809; U.S. Patent No. 9,119,528; and U.S. Patent No. 9,119,529.

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[0398] The above description presents the best mode of carrying out the invention as contemplated, and the best mode of making and using the manner and process of the invention, in complete, clear, concise, and precise terms, so as to enable any person skilled in the art to which the invention pertains to make and use the invention. However, the invention is susceptible to fully equivalent modifications and alternative constructions from what has been discussed above. Therefore, the invention is not limited to the specific embodiments disclosed. On the contrary, the invention encompasses all modifications and alternative constructions that fall within the spirit and scope of the invention as generally expressed by the appended claims, which specifically point out and expressly claim the subject matter of the invention. Although the present disclosure has been described and illustrated in detail in the drawings and the foregoing description, this illustration and description are to be regarded as illustrative or exemplary rather than restrictive.

[0399] All references cited herein are incorporated herein by reference in their entirety. To the extent that publications and patents or patent applications incorporated by reference conflict with the disclosure contained in this specification, the specification is intended to supersede and / or take precedence over any such conflicting disclosure.

[0400] Unless otherwise defined, all terms (including technical and scientific terms) are to be given their ordinary and customary meaning to those skilled in the art and are not to be limited to special or customary meanings unless expressly so defined herein. It should be noted that the use of a particular term when describing certain features or aspects of the present disclosure should not imply that the term is redefined herein to be limited to encompass any particular characteristic of the feature or aspect of the present disclosure to which the term is associated. The terms and phrases used in this application and variations thereof, especially in the appended claims, should be interpreted as open ended and not restrictive unless expressly stated otherwise. As an example of the foregoing, the term 'comprising' should be understood to mean 'including without limitation', 'including but not limited to' or similar meanings; the term 'including' as used herein is synonymous with 'including', 'containing' or 'characterized by' and is inclusive or open ended and does not exclude additional, unstated elements or method steps; the term 'having' should be interpreted as 'having at least'; the term 'including' should be interpreted as 'including but not limited to'; the term 'example' is used to provide an illustrative example of the item under discussion rather than an exhaustive or limiting list thereof; for example, 'known', 'normal', Adjectives such as 'standard' and terms of similar import should not be construed as limiting the described items to a given time period or to items available with respect to a given time, but rather should be understood to encompass known, normal, or standard technologies that may be available or known at any time now or in the future; and the use of terms such as 'preferably', 'preferred', 'required', or 'desirable' and words of similar import should not be understood to imply that certain features are critical, essential, or even important to the structure or function of the invention, but rather are intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the invention. Similarly, a group of items associated with the conjunction 'and' should not be understood as requiring that each and every one of those items be present in the group, but rather should be understood as 'and / or' unless expressly stated otherwise. Similarly, a group of items associated with the conjunction 'or' should not be understood as requiring mutual exclusivity among the group, but rather should be understood as 'and / or' unless expressly stated otherwise.

[0401] Where a range of values ​​is provided, it is understood that the upper and lower limits of that range and every intervening value therebetween are encompassed within the embodiments.

[0402] With respect to the use of any plural and / or singular terms herein in general, those skilled in the art may translate from the plural to the singular and / or from the singular to the plural as appropriate in the context and / or application. For the sake of clarity, various singular / plural permutations may be explicitly stated herein. The indefinite article 'a' does not exclude a plurality. A single processor or other unit may fulfil the functions of several items stated in a claim. The mere fact that certain measures are stated in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

[0403] Those skilled in the art will further understand that if a specific number of introduced claim statements is intended, this intention will be expressly stated in the claim, and in the absence of such a statement, such intention is absent. For example, as an aid to understanding, the subsequently appended claims may contain the use of the introductory phrases 'at least one' and 'one or more' to introduce claim statements. However, the use of these phrases should not be construed to imply that the introduction of a claim statement by the indefinite article 'a' limits any particular claim containing such introduced claim statement to embodiments containing only one such statement, even when the same claim contains the introductory phrases 'one or more' or 'at least one' and an indefinite article such as 'a' (e.g., 'a' should generally be interpreted to mean 'at least one' or 'one or more'); the same applies to the use of definite articles to introduce claim statements. In addition, even if a specific number of introduced claim statements is expressly stated, those skilled in the art will recognize that such statement should generally be interpreted to mean at least the stated number (e.g., the mere statement 'two statements' without other modifiers generally means at least two statements, or two or more statements). Furthermore, in those instances where a convention similar to 'at least one of A, B, and C, etc.' is used, it is generally constructed with the expectation that one skilled in the art will understand the meaning of the convention (e.g., 'a system having at least one of A, B, and C' will include, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In those instances where a convention similar to 'at least one of A, B, or C, etc.' is used, it is generally constructed with the expectation that one skilled in the art will understand the meaning of the convention (e.g., 'a system having at least one of A, B, or C' will include, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Those skilled in the art will further understand that virtually any disjunctive word and / or phrase presenting two or more alternatives, whether in the description, claims, or drawings, should be understood to contemplate the possibility of including one, either, or both of the items. For example, the phrase 'A or B' will be understood to include the possibility of 'A' or 'B' or 'A and B'.

[0404] All numbers used in the specification expressing the amounts of ingredients, reaction conditions, and the like should be understood as being modified in all instances by the term 'about'. Therefore, unless otherwise indicated, the numerical parameters set forth herein are approximate values ​​that may vary depending on the desired properties sought to be obtained. At a minimum, and without attempting to limit the application of the doctrine of equivalents to the scope of any claim in any application claiming priority to the present application, each numerical parameter should be interpreted in light of the number of significant digits and ordinary rounding techniques.

[0405] Furthermore, although the foregoing has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be apparent to those skilled in the art that certain changes and modifications may be practiced. Therefore, the description and examples should not be construed as limiting the scope of the invention to the particular embodiments and examples described herein, but rather to encompass all modifications and alternatives that come within the true scope and spirit of the invention.

Claims

1. An applicator for applying an on-skin sensor assembly to the skin of a subject, the applicator comprising: an applicator housing operatively coupled to the disposable housing, the disposable housing configured to receive an electronics unit, and the electronics unit configured to generate analyte information based on the signal from the sensor; an insertion assembly comprising an insertion member configured to insert the sensor into the skin of the subject; a first drive assembly containing a first amount of stored energy, the first drive assembly configured to drive the insertion member in a distal direction during a first phase and in a proximal direction during a second phase; as well as a second drive assembly containing a second amount of stored energy, the second drive assembly being configured to drive the insertion member in the proximal direction, Wherein the first drive assembly is configured to activate the second drive assembly while driving the insertion member in the proximal direction during the second stage.

2. The applicator of claim 1, wherein the drive assembly is self-reversing from the first stage to the second stage. 3 . The applicator of claim 1 , wherein the first drive assembly is configured to drive the insertion member in the proximal direction after the insertion member reaches an insertion position.

4. The applicator of claim 1, wherein the first drive assembly is configured to activate the second drive assembly in response to the first drive assembly reaching a trigger position during the second stage.

5. The applicator of claim 1 , further comprising a resistance member operatively coupled to the insertion assembly during the first stage, wherein the second drive assembly is configured to decouple the resistance member from the insertion assembly during the second stage.

6. The applicator of claim 5, wherein the second amount of stored energy is sufficient to decouple the resistance member from the insertion assembly.

7. An applicator according to claim 5 or 6, wherein the insertion assembly comprises a cannula.

8. The applicator of claim 7, wherein the distal end of the insertion member extends toward the distal end of the cannula during the second stage.

9. The applicator of claim 7, wherein the insertion member is configured to advance through the cannula during the first stage.

10. The applicator of claim 7, wherein the resistance member is releasably coupled to the cannula.

11. The applicator of claim 7, wherein the cannula is fixed relative to the disposable housing when the insertion member is moved distally.

12. The applicator of claim 1, wherein at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion to linear motion.

13. The applicator of claim 1, wherein at least one of the first drive assembly and the second drive assembly comprises a scotch yoke, a crank slider, a barrel cam, or a rack and pinion.

14. The applicator of claim 1, wherein at least one of the first drive assembly and the second drive assembly comprises a spring.

15. The applicator of claim 1, wherein at least one of the first drive assembly and the second drive assembly comprises a torsion spring.

16. The applicator of claim 1, wherein the second amount of stored energy is greater than the first amount of stored energy.

17. The applicator of claim 1, further comprising a ratchet member configured to prevent back driving of the first drive assembly.

18. A method of applying an on-skin sensor assembly to the skin of a subject, the method comprising: An assembly is provided, comprising an applicator housing operatively coupled to the disposable housing, An insert assembly comprising an insert member, a first drive assembly containing a first amount of stored energy, and a second drive assembly containing a second amount of stored energy; as well as activating a trigger of the assembly, wherein activating the trigger causes the first drive assembly to drive the insertion member in a distal direction during a first phase, wherein a sensor is inserted into the skin of the subject, and the first drive assembly to drive the insertion member in a proximal direction during a second phase, wherein the first drive assembly activates the second drive assembly while driving the insertion member in the proximal direction during the second phase, and The second drive assembly drives the insertion member in the proximal direction during the second stage.

19. The method of claim 18, further comprising installing an electronics unit in the disposable housing, the electronics unit configured to generate analyte information based on the signal from the sensor.

20. The method of claim 18, wherein the assembly further comprises a resistance member coupled to the insertion assembly.

21. The method of claim 20, wherein activating the trigger causes the second drive assembly to decouple the resistance member from the insertion assembly during the second stage.

22. The method of claim 20, wherein the second amount of stored energy is sufficient to decouple the resistance component from the insert assembly.

23. The method of claim 20, wherein the resistance member comprises a seal.

24. The method of claim 18, wherein the insertion assembly comprises a cannula.

25. The method of claim 18, wherein the second amount of stored energy is greater than the first amount of stored energy.

26. The method of claim 18, wherein at least one of the first drive assembly and the second drive assembly is configured to convert rotational motion to linear motion.

27. The method of claim 18, wherein the first drive assembly activates the second drive assembly in response to the first drive assembly reaching a trigger position during the second stage.

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