Insertion device and method for inserting a medical device

Abstract

An insertion device (110) for inserting at least one insertable part of a medical device (112) into a body tissue (114) of a subject along an insertion axis (116) is disclosed. The insertion device (110) comprises an insertion tool (117), a cap (122), an insertion sleeve (124) and a guide sleeve (126) configured for guiding the insertion sleeve (124) therein, wherein the insertion sleeve (124) and / or the cap (122) in conjunction with the guide sleeve (126) form at least one friction pairing (128) comprising at least one elastic member (130) and at least one profile member (132), wherein at least one of the cap (122) and the insertion sleeve (124) comprises one of the at least one elastic member (130) and the at least one profile member (132) of the friction pairing (128) and wherein the guide sleeve (126) comprises the at least one other of the at least one elastic member (130) and the at least one profile member (132) of the friction pairing (128), wherein, for inserting the at least one insertable part of the medical device (112), the cap (122), the insertion tool (117) and the insertion sleeve (124) are configured to perform a movement (138) relative to the guide sleeve (126) from a distal position (134) to a proximal position (136) in a telescopic fashion, wherein the friction pairing (128), in response to an insertion force (140) acting on one or more of the cap (122) and the insertion sleeve (124) in a direction parallel to the insertion axis (116), is configured to provide a friction force changing with advancing of the movement (138) of one or more of the cap (122) and the insertion sleeve (124) from the distal position (134) to the proximal position (136), wherein in the distal position (136), the elastic member (130) and the profile member (132) of the at least one friction pairing (128) are spaced apart from each other, wherein one or both of the elastic member and the profile member comprises at least one material having a friction coefficient μ of 0.04 ≤ μ ≤ 0.12, specifically 0.06 ≤ μ ≤ 0.08. Further disclosed are an insertion system (111) and a method of inserting at least one insertable part of a medical device (112) into a body tissue (114) of a subject.

Description

[0001] Insertion device and method for inserting a medical device

[0002] Technical Field

[0003] The invention relates to an insertion device, an insertion system and a method for inserting at least one insertable part of a medical device into a body tissue of a subject. The medical device may specifically be configured for detecting at least one analyte in a body fluid of the subject. The insertion device and the method may be applied in the field of continuous monitoring of the analyte in the body fluid of the subject, specifically in the field of home care and in the field of professional care, such as in hospitals. Other applications, however, are also feasible.

[0004] Background art

[0005] Monitoring certain body functions, more particularly monitoring one or more analyte concentrations such as one or more metabolite concentrations in a body fluid of a subject plays an important role in the prevention and treatment of various diseases. Such analytes can by way of example, but not exclusively, include glucose, lactate, cholesterol or other types of analytes and metabolites. Without restricting further possible application, the invention will be described in the following text with reference to glucose monitoring. However, additionally or alternatively, the invention can also be applied to other types of analytes.

[0006] Blood glucose monitoring, besides by using optical measurements, specifically may be performed by using electrochemical biosensors. In addition to so-called spot measurements, in which a sample of a body fluid is taken from a used in a targeted fashion and is examined with respect to the analyte concentration, continuous measurements are increasingly becoming established. Thus, in the recent past, continuous measuring of interstitial tissue (also referred to as continuous monitoring, CM) for example, has been established as another important method for managing, monitoring and controlling a diabetes state.

[0007] In the process, an active sensor region is applied directly to a measurement site, which is generally arranged in an interstitial tissue, and, for example, converts glucose into electrical charge by using an enzyme (e.g. glucose oxidase, GOD) the charge of which is related to the glucose concentration and can be used as a measurement variable. Examples of such transcutaneous measurement systems are described in US 6,360,888 Bl or in US 2008 / 0242962 Al.

[0008] Hence, current continuous monitoring systems typically are transcutaneous systems or subcutaneous systems. This means that the sensor or at least a measuring portion of the sensor is arranged under the skin of the user. Typically, for arranging the sensor under the skin, an insertion instrument is used. Such insertion instruments are generally known.

[0009] US 11,266,335 B2 describes an apparatus for insertion of a medical device in the skin of a subject, as well as methods of inserting medical devices. Embodiments include removing a substantially cylindrical cap from an inserter to expose a substantially cylindrical sleeve, removing a cover from a substantially cylindrical container holding sensor components, and fitting the sensor components into the inserter.

[0010] WO 2023 / 239929 Al describes apparatuses, systems, and methods for deploying a medical device to skin of a host. The medical device may comprise a transcutaneous analyte sensor applied to the skin of a host.

[0011] Despite the advantages provided for by known devices and methods, still several technical challenges remain. Specifically, there is a continuing need for improving the handling of insertion systems to increase user convenience without compromising safety and measurement accuracy.

[0012] Problem to be solved

[0013] It is therefore desirable to provide an insertion device and an insertion system for inserting at least one insertable part of a medical device into a body tissue of a subject along an insertion axis as well as a method for inserting at least one insertable part of a medical device into a body tissue of a subject. Specifically, conveniently usable devices, systems and methods are desirable, which require a minimum amount of handling force, while at the same time minimizing the risk of accidental misplacement during insertion, thus still allowing for a safe and controlled insertion of at least the insertable part of the medical device into the body tissue of the subject.

[0014] Summary

[0015] This problem is addressed by an insertion device, an insertion system and a method for inserting at least one insertable part of a medical device into a body tissue of a subject with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.

[0016] As used in the following, the terms “have”, “comprise” or “include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions “A has B”, “A comprises B” and “A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

[0017] Further, it shall be noted that the terms “at least one”, “one or more” or similar expressions indicating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions “at least one” or “one or more” will not be repeated, non-withstanding the fact that the respective feature or element may be present once or more than once.

[0018] Further, as used in the following, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

[0019] In a first aspect of the present invention, an insertion device for inserting at least one insertable part of a medical device into a body tissue of a subject along an insertion axis is disclosed.

[0020] The term “subject” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically relates to a human being or an animal, independent from the fact that the human being or animal, respectively, may be in a healthy condition or may suffer from one or more diseases. The subject may be a patient. As an example, the subject may be a human being or an animal suffering from diabetes. The subject may be a user, e.g. a patient, intending to monitor an analyte value, such as a glucose value, in the user’s body tissue and / or to deliver medication, such as insulin, into the user’s body tissue. However, in an embodiment, the user of the insertion device may be different from the subject. Additionally or alternatively, the invention may be applied to other types of users or patients. As an example, when a person, such as medical staff, applies, e.g. uses, the insertion device, for inserting at least one insertable part of the medical device into a patient, then the person, e.g. medical staff, is referred to as “user”, while the patient is referred to as “subject”. Nevertheless, herein, the terms “user” and ’’subject” may be used interchangeably.

[0021] The term “medical device” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary element or article being configured for use in the field of medical technology, exemplarily in the field of medical analytics or medical diagnostics. The medical device may be configured for performing at least one medical function and / or for being used in at least one medical process, such as one or more of a therapeutic process, a diagnostic process or another medical process.

[0022] For example, the medical device may be or may comprise at least one analyte sensor for detecting at least one analyte in a bodily fluid of the subject, such as in a bodily fluid contained in a body tissue of the subject.

[0023] The analyte sensor may be configured for being used in qualitatively and / or quantitatively detecting the at least one analyte. The term “analyte” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a chemical and / or biological substance which takes part in the metabolism of the body of the subject. Specifically, the analyte may be a metabolite or a combination of two or more metabolites. As an example, the analyte may be selected from the group consisting of: glucose, lactate, triglycerides, cholesterol. Still, other analytes or combinations of two or more analytes may be detected. The body tissue specifically may be or may comprise fatty tissue and / or interstitium. Other types of body tissue, however, are feasible.

[0024] The term “analyte sensor” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a sensor which is capable of qualitatively or quantitatively detecting the presence and / or the concentration of the at least one analyte.

[0025] The analyte sensor may be an electrochemical analyte sensor. The analyte sensor may comprise at least two electrodes. Specifically, the analyte sensor may comprise at least one two- electrode sensor. The two-electrode sensor may comprise precisely two electrodes, such as a working electrode and at least one further electrode such as a counter electrode, in particular a working electrode and a combined counter / reference electrode. The working electrode may comprise a working electrode pad and, optionally, at least one test chemical disposed thereon. The counter electrode may comprise a conductive electrode pad. Additionally and optionally, one or more redox materials may be disposed thereon. The analyte sensor may further comprise one or more leads for electrically contacting the electrodes. The leads may, during insertion or at a later point in time, be connected to an electronics unit, such as one or more measurement devices adapted for measuring electrical currents and / or electrical voltages, such as to one or more potentiostats. Preferably, the leads already connected to the electronics unit before insertion of the analyte sensor.

[0026] Specifically, the analyte sensor may be a strip-shaped analyte sensor having a flexible substrate and the electrodes disposed thereon. As an example, the analyte sensor may have a total length of 5 mm to 50 mm, specifically a total length of 7 mm to 30 mm. The term “total length” within the context of the present invention relates to the overall length of the analyte sensor which means the portion of the analyte sensor which is inserted and the portion of the analyte sensor which is connected to the electronics unit. The portion of the analyte sensor which is inserted is also called the in-vivo portion, the portion of the analyte sensor which is connected to the electronics unit is also called the ex vivo portion. Preferably, the in vivo portion has a length in the range from 3 mm to 12 mm.

[0027] The analyte sensor may further comprise a biocompatible cover, such as a biocompatible membrane which fully or partially covers the analyte sensor and which prevents the test chemical from migrating into the body tissue and which allows for a diffusion of the bodily fluid and / or the analyte to the electrodes.

[0028] Other embodiments of electrochemical analyte sensors, such as three-electrode sensors, may be feasible. For example, the three-electrode sensor may comprise, in addition to the working electrode and the counter electrode, a reference electrode.

[0029] In another embodiment, the analyte sensor may be an optical analyte sensor. For example, the analyte sensor may comprise a flexible light guide with glucose sensitive coating at its end and / or a tube like carrier with functional elements at inner or outer walls. Other embodiments of the analyte sensor may be possible too. For potential embodiments of analyte sensors, reference may be made to the above-mentioned prior art documents.

[0030] The term “inserting” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an action or process of one or more of transcutaneously or subcutaneously implanting and / or positioning at least the insertable part of the medical device into the body tissue of the user. The medical device, such as the analyte sensor, may fully or partially be inserted into the body tissue. The insertion of the medical device may be performed by using the insertion device. After insertion, the medical device or at least a part of the medical device may remain in the body tissue of the subject for a predetermined period of time, such as for several hours, specifically for one or more days, more specifically for up to one week, even more specifically for up to two weeks or even more. The medical device may be configured for continuously monitoring and / or detecting the analyte in the body fluid of the subject.

[0031] The term “insertion device” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a device configured for inserting at least the insertable part of the medical device into the body tissue. The insertion device may be configured for transcutaneously or subcutaneously inserting the medical device into the body tissue, such as by performing an incision or a puncture in a skin of the subject and by transferring the medical device fully or partially into the body tissue. The insertion device may be removed fully or partially after inserting the medical device at least partially into the body tissue of the subject.

[0032] The insertion device comprises an insertion tool. Further, the insertion device comprises a cap. Furthermore, the insertion device comprises at least one insertion sleeve and at least one guide sleeve configured for guiding the insertion sleeve therein. The insertion sleeve and / or the cap in conjunction with the guide sleeve form at least one friction pairing. The friction pairing comprising at least one elastic member and at least one profile member, wherein at least one of the cap and the insertion sleeve comprises one of the at least one elastic member and the at least one profile member of the friction pairing and wherein the guide sleeve comprises the at least one other of the at least one elastic member and the at least one profile member of the friction pairing. For inserting the at least one insertable part of the medical device, the cap, the insertion tool and the insertion sleeve are configured to perform a movement relative to the guide sleeve from a distal position to a proximal position in a telescopic fashion. The friction pairing, in response to an insertion force acting on one or more of the cap and the insertion sleeve in a direction parallel to the insertion axis, is configured to provide a friction force changing with advancing of the movement of one or more of the cap and the insertion sleeve from the distal position to the proximal position, specifically from their respective distal positions to their respective proximal positions. In the distal position, e.g. in the insertion device’s distal position, specifically in the arrangement in which the cap, the insertion sleeve and the insertion tool are in their respective distal positions, the elastic member and the profile member of the at least one friction pairing are spaced apart from each other.

[0033] In particular, in order for inserting the at least one insertable part of the medical device into the body tissue of the subject, the insertion force may be greater than the friction force provided by the friction pairing in response to the insertion force moving the cap, the insertion tool and the insertion sleeve relative to the guide sleeve from their respective distal positions to their respective proximal positions.

[0034] As an example, the at least one friction paring may be formed, in conjunction, by the insertion sleeve and the guide sleeve. Additionally or alternatively, the at least one friction pairing may be formed, in conjunction, by the cap and the guide sleeve.

[0035] The present invention may allow for a convenient and safe insertion, since the at least one friction pairing, by providing the friction force changing with the advancing movement from the distal position to the proximal position, may prevent accidental and / or unintentional movement of the insertion device during insertion, thereby reducing the risk of misinsertion of the at least one insertable part of the medical device. Furthermore, the friction pairing may allow for a stable contact between the insertion device and the skin of the subject during the insertion, while still the friction force provided by the friction pairing may be conveniently low and manageable, such as to allow for a one-handed insertion by the subject. Specifically, the insertion sleeve and / or the cap in conjunction with the guide sleeve, in particular the at least one profile member and the at least one elastic member of the insertion sleeve and / or the cap and the guide sleeve respectively, forming the at least one friction pairing, may require a high enough insertion force to prevent unintentional misplacement of the insertion device during insertion, while still allowing easy, e.g. one-handed, handling of the insertion device for performing a controlled and intended insertion.

[0036] The term “insertion tool” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary object or element, which may be insertable at least partially into the body tissue, particularly in order to deliver or to transfer a further element. The insertion tool may be configured for supporting the insertion of at least the insertable part of the medical device, specifically when driven from its distal position to its proximal position. The insertion tool may comprise a tip or a sharp end for inserting the medical device into the body tissue. The insertion tool may be or may comprise an insertion cannula or an insertion needle. The term “insertion cannula” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a hollow needle, which may be at least partially slotted. The medical device may be received within the insertion cannula, such as within a lumen of the insertion cannula. The term “insertion needle” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a compact needle, specifically without a slot and without any hollow parts. The medical device may be received on an outer surface of the insertion needle.

[0037] After insertion, the medical device may remain in the body tissue of the subject. The insertion tool, however, may be retracted from the body tissue of the subject into the insertion device after inserting the medical device, specifically the at least one insertable part of the medical device. For retracting the insertion tool the insertion device may comprise an insertion tool retractor. The term “insertion tool retractor” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to at least one element of the insertion device configured for retracting the insertion tool. The insertion tool retractor may be configured for suspending the insertion tool during insertion movement and pull it out from the skin of the subject, specifically after the insertion, in a retraction movement. As an example, the insertion tool retractor may be configured for retracting the insertion tool from the body tissue of the subject when driven from its proximal position to its distal position, specifically to its distal retraction position.

[0038] The term “cap” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary shaped element configured for fully or partially enclosing one or more components of the insertion device and / or for providing protection for these one or more components, such as against mechanical influence and / or humidity. The cap may surround and / or may enclose fully or partially one or more further components, such as the insertion tool, e.g. the insertion tool retractor, the insertion sleeve and the guide sleeve, specifically the insertion sleeve and / or the cap and the guide sleeve forming, in conjunction, the at least one resistance pairing. The term “at least partially surround”, also referred to as “at least partially enclose”, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to embodiments wherein the cap fully surrounds the one or more further components of the insertion device and to embodiments wherein the cap may surround at least a part of the one or more further components. For example, the cap of the insertion device may fully surround the insertion sleeve, the insertion tool and optionally the insertion tool retractor. The cap may also at least partially surround the guide sleeve and, thus, may fully cover the guide sleeve except for a proximal end of the guide sleeve. The cap may be arranged such that it surrounds and / or encloses the further components of the insertion device, wherein a proximal side of the insertion device may be at least partially uncovered by the cap allowing contacting the subject’s skin with the guide sleeve and movement of the insertion tool out of the insertion device, i.e. through the subject’s skin and into the subject’s body tissue. The cap when being in the proximal position may align with the proximal end of the guide sleeve. The proximal side may be the side of the insertion device providing a contact area or region with the subject’s skin. A distal side may be a side of the insertion device opposite to the proximal side. The cap may be or may comprise a rigid cap, such as a rigid cap made of one or more of a plastic material, a metallic material or a cardboard material.

[0039] The cap specifically may be essentially rotationally symmetric, e.g. by having an axial rotational symmetry about an axis such as a cylinder axis or axis of extension, specifically around the insertion axis. The term “essentially rotationally symmetric” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the fact that the cap may be fully rotationally symmetric or may comprise at least one part being rotationally symmetric, whereas other parts of the cap may exhibit a form diverging from the rotational symmetry. The cap may be designed as a cylinder, a hemisphere or as a dome. The cap may comprise an inner structure, which may not be rotationally symmetric. An outer shape of the cap may also be asymmetrical, e.g. may be shaped ergonomically to be held by a user’s hand. The inner structure of the cap may correspond to an outer shape and / or structure of the insertion sleeve. For example, the inner structure of the cap may be cylindrical or prismatic.

[0040] Further, the cap may be configured for interacting with and / or holding at least one other component of the insertion device together. Specifically, the cap may be configured to transfer movement onto at least one other component of the insertion device, such as onto one or more of the insertion tool and the insertion sleeve and optionally the insertion tool retractor. Thus, as an example, by the movement of the cap from its distal position to its proximal position also the insertion tool and the insertion sleeve and optionally the insertion tool retractor may be moved from their respective distal positions to their respective proximal positions.

[0041] The term “insertion sleeve” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an element configured for at least partially enclosing the insertion tool. The insertion sleeve itself may be enclosed fully or partially by the guide sleeve and the cap of the insertion device.

[0042] The insertion sleeve may be prismatic. The insertion sleeve may be essentially rotationally symmetric, specifically in accordance with the symmetry of the cap and the guide sleeve. For example, the cap and the guide sleeve may have an axial rotational symmetry about an axis such as a cylinder axis or axis of extension, the insertion sleeve may have a similar axial rotational symmetry. The insertion sleeve may be configured for guiding the insertion tool and / or optionally the insertion tool retractor. For example, for guiding a cylindrical-shaped insertion tool retractor, the insertion sleeve may comprise a rotational symmetric hollow center. The rest of the insertion sleeve may have an irregular cross section.

[0043] The term “guide sleeve” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an enclosure of one or more components configured for guiding at least one movement of the enclosed components. The guide sleeve may fully or partially enclose the insertion sleeve and / or optionally the insertion tool retractor. The guide sleeve may be partially enclosed by the cap.

[0044] The guide sleeve may be essentially rotationally symmetric, specifically in accordance with the symmetry of the cap of the insertion device, in particular of the inner structure of the cap of the insertion device. For example, in case the cap may have an axial rotational symmetry about an axis such as a cylinder axis or axis of extension, the guide sleeve may have a similar axial rotational symmetry.

[0045] The guide sleeve may be movable with respect to the cap of the insertion device. For example, when using the insertion device, the guide sleeve may be configured for sliding into the cap of the insertion device. The guide sleeve, in particular the proximal end of the guide sleeve, may be in contact with the user’s skin when the insertion device is used.

[0046] Further, the guide sleeve may be movable with respect to the insertion sleeve and may be configured for guiding the insertion sleeve within its inner space. For example, when using the insertion device, the movement of the cap may drive a movement of the insertion sleeve, wherein the direction of the movement of the insertion sleeve may be guided by the guide sleeve, e.g. by an inner surface of the guide sleeve, for example along the insertion axis. Specifically, the guide sleeve may prevent the insertion sleeve from performing a tilting movement in response to the movement of the cap.

[0047] In conjunction, the guide sleeve and one or more of the insertion sleeve and the cap form at least one friction pairing. The friction pairing comprises at least one elastic member and at least one profile member.

[0048] The term “elastic member” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrarily formed elastic object protruding from at least one surface of an element. In particular, the elastic member may be elastically deformable. The elastic member may comprise at least one fixed end, where the elastic member is fixed to the surface of the element, for example to the guide sleeve or to one of the insertion sleeve and the cap. Further, the elastic member may comprise at least one free end, directed towards the other one of the guide sleeve and one of the insertion sleeve and the cap, respectively. As an example, the elastic deformation of the elastic member may be or may comprise a displacement of a position of the free end of the elastic member by at least 10 %, specifically at least 30%, more specifically at least 50%, of a maximum distance between the free end and the fixed end.

[0049] The term “profile member” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an obstacle arranged at a surface of an element, such as a cavity and / or indentation in at least one surface of an element or to a protrusion from a surface on the element, providing a profile according to which a movement of another object and / or element gliding on the surface of the element on which the profile member is located is deflected. In particular, during the movement from the distal position to the proximal position, the profile member, specifically the cavity or protrusion, may be configured for deflecting a position of the free end of the elastic member, wherein a surface profile of the profile member may be such that the position deflection changes with advancing of the movement.

[0050] However, in the distal position, e.g. in the insertion device’s distal position, specifically in the arrangement in which the cap, the insertion sleeve and the insertion tool are in their respective distal positions, the elastic member and the profile member of the at least one friction pairing are spaced apart from each other. Thus, as an example, in the distal position, the free end of the elastic member may be spaced apart from a surface of the profile member. Specifically, in the distal position, the elastic member may be in a relaxed, non-deformed state.

[0051] The term “friction pairing” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an at least two-piece interaction mechanism configured to provide detectable friction force to a user when performing the insertion by using the insertion device. In particular, the friction pairing may be configured for providing a friction force in reaction to the two pieces, specifically the elastic member and the profile member, being forcefully moved against each other, i.e. by the insertion force. Specifically, the friction pairing may provide the friction force in a direction along the insertion axis, when the insertion sleeve is moved from its distal position to its proximal position within the guide sleeve or when the cap is moved from its distal position to its proximal position with respect to the guide sleeve, in particular along the insertion axis. The friction force may for example be provided by the elastic member, specifically its free end, being forced to perform a deflection movement by the profile member. In particular, the friction force may be configured to slow down the movement of the insertion sleeve and / or the cap relative to the guide sleeve driven by the insertion force. As an example, the friction force of the friction pairing may be defined by the elasticity of the elastic member and by the profile of the profile member, i.e. the form and / or shape of the surface of the profile member over which the elastic member glides. Further, the material properties of the elastic member and of the profile member may influence the friction force of the friction pairing.

[0052] As outlined above, for inserting the at least one insertable part of the medical device, the cap, the insertion tool, the insertion sleeve and optionally the insertion tool retractor are movable relative to the guide sleeve from the distal position to the proximal position in a telescopic fashion, by applying the insertion force on one or more of the cap and the insertion sleeve. From the distal position to the proximal position, the friction force, provided by the friction pairing formed by the guide sleeve and one of the insertion sleeve and the cap in a direction parallel to the insertion axis, in response to the insertion force, changes. During the insertion, the guide sleeve may be regarded as a fix or non-moving component of the insertion device since the guide sleeve is positioned on the subject’s skin. The other components, such as the insertion tool, the insertion sleeve, the cap and optionally the insertion tool retractor may move in a proximal direction, e.g. along the insertion axis, relative to the skin of the subject and relative to the guide sleeve.

[0053] The term “distal position” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a position specification indicating a position of the insertion device and / or any parts thereof in relation to the subject in which the insertion tool and / or the cap are furthermost from the proximal side of the insertion device. Specifically, for inserting the insertable part of the medical device, the insertion device may be brought into contact with a skin site of the subject. The distal position may refer to a position being distanced to the skin site of the subject. Specifically, the distal position may refer to a most distanced position with regard to the skin site of the subject.

[0054] The distal position may be an initial position of the insertion device prior to the insertion movement of the insertion device and / or any parts thereof. Each component of the insertion device may have its own and / or individual distal position. For example, the cap, the insertion tool, the insertion sleeve and optionally the insertion tool retractor may each have their own and / or individual distal positions, respectively.

[0055] Prior to insertion, the cap, the insertion tool, the insertion sleeve and optionally the insertion tool retractor may be in their distal position(s) and may be ready for inserting the insertable part of the medical device into the body tissue of the subject. After insertion, the cap and optionally the insertion tool retractor may be moved back to their distal positions, respectively, and the insertion tool may specifically be retracted from the body tissue when the insertion tool retractor may be back in its distal position and thus the insertion tool may also be moved to its distal position. The distal position of the insertion device and / or any parts after the insertion of the medical device, specifically of at least the insertable part of the medical device, such as the distal position after retraction of the insertion tool, may also be referred to as “distal retraction position”. The distal retraction position of one or more of the components of the insertion device may be the same as the distal position, for example as an initial distal position. For example, the initial distal position may be the same as the distal retraction position. In particular, as an example, the distal position of the cap prior to the insertion may be the same as after the insertion. However, alternatively, the distal retraction position of at least one of the components of the insertion device may differ from the initial distal position of the same component. Thus, as an example, the distal position if the insertion tool prior to the insertion may differ from the distal position of the insertion tool after its retraction.

[0056] The term “proximal position” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a position specification indicating a position of the insertion device and / or any parts thereof in relation to the subject in which the cap, the insertion tool, the insertion sleeve and / or optionally the insertion tool retractor are closest to the proximal side of the insertion device. Specifically, for inserting at least the insertable part of the medical device, the insertion device may be brought into contact with the skin site of the subject. The proximal position may refer to a position being in close proximity to the skin site of the subject. Each component of the insertion device may have its own and / or individual proximal position. For example, the cap, the insertion tool, the insertion sleeve and optionally the insertion tool retractor may each have their own and / or individual proximal position(s), respectively. In case the cap, the insertion tool, the insertion sleeve and optionally the insertion tool retractor are in their proximal position, at least the insertable part of the medical device may be inserted into the body tissue of the subject. During insertion of the medical device, the guide sleeve may be in contact with the skin site of the subject and, thus, may be, during insertion, in its proximal position.

[0057] The movement of the cap together with the insertion tool, the insertion sleeve and optionally the insertion tool retractor from its distal position to its proximal position may be driven by an action of the user and / or subject. Specifically, the action of the user and / or subject may be or may comprise applying the insertion force to one or both of the cap and the insertion sleeve by the user, such as by manually pressing and / or pushing the cap and / or the insertion sleeve downward towards the proximal position, in particular towards the subject’s skin. In particular, the user and / or subject when pressing and / or pushing the cap may be required to apply the insertion force for overcoming the friction force provided by the friction pairing in response to the insertion force in order to move the cap, the insertion tool and the insertion sleeve from its distal position to its proximal position.

[0058] Further resistances may have to be overcome in order to start the movement from the distal position to the proximal position, such as resistance force, also referred to as insertion release force, required for actuating and / or initiating the movement, as described further below. This resistance force may be provided by a resistance member, i.e. an initial obstacle, being positioned in the path of the elastic member and / or any other object and / or element positioned on a surface of the guide sleeve and one of the cap and the insertion sleeve.

[0059] The insertion device may specifically be a mechanical insertion device, which preferably may be operated by hand, preferably without the need of electrical or electromechanical actuators. However, other embodiments are feasible.

[0060] The insertion movement may be completed when the cap and / or the insertion sleeve are in their respective proximal positions. The cap and / or the insertion sleeve when being in their proximal positions may align with the proximal end of the guide sleeve. Thus, in its proximal position, a proximal end of the cap and / or the insertion sleeve may contact the subject’s skin in a similar way as the guide sleeve may contact the subject’s skin. A movement of the cap, optionally together with the insertion tool retractor, from its proximal position to its distal position may be driven by relieving the action of the user and / or subject. Specifically, the user and / or subject may reduce or may stop applying the insertion force thereby initiating movement of the cap, optionally together with the insertion tool retractor, from its proximal position to its distal position. The term “relieving” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a process of completely stopping applying the action and to a process of partially stopping applying the action such as by reducing or diminishing the force.

[0061] Optionally, the insertion device may comprise a spring configured for driving the insertion tool retractor to move from its proximal position to its distal position, specifically to its distal retraction position. Specifically, the spring may be configured for retracting the insertion tool retractor after insertion of the at least one insertable part of the medical device. The term “spring” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an element which, when being compressed or stretched from its resting position, may exert a force opposing to the compression or stretch. The spring may be configured for applying the force to one or more further elements of the insertion device. Specifically, the spring may be compressed or stretched when the at least one insertable part of the medical device is inserted into the body tissue or, alternatively, the spring may already be in a compressed or stretched state, such as in a pre-tensioned state, prior to use of the insertion device. The spring may be connected to the insertion tool retractor. The spring may be pre-tensioned, specifically in between the insertion sleeve and the insertion tool retractor. In particular, the spring may be located in a distal receptacle of the insertion sleeve. Provided that the user and / or subject applies the insertion force to the cap and / or to the insertion sleeve, the spring may not be able to move the insertion tool retractor and the cap from their proximal position to their distal position, respectively. The spring may be actuable by the user and / or subject releasing the insertion force applied to the cap and / or to the insertion sleeve. Specifically, the spring may be configured to drive the movement of the insertion tool retractor and of the cap from their proximal positions to their distal positions, specifically to their distal retraction positions. However, the spring may only be able to move from its compressed position towards its resting position, thereby applying the spring force, after the cap and / or insertion tool retractor have reached their proximal positions, respectively, and when the insertion force applied to the cap and / or to the insertion sleeve is reduced.

[0062] In particular, the cap, the insertion tool, the insertion sleeve and the guide sleeve may be formed such that a telescopic movement of the cap, the insertion tool and the insertion sleeve relative to the guide sleeve is possible. Thus, the cap, the insertion tool and the insertion sleeve may all be arranged coaxial to the guide sleeve, and may be formed such that they may all be stacked at least partially into each other.

[0063] The term “telescopic movement” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an extension and / or retraction movement of at least two at least partially stackable elements and / or objects, in which the participating elements and / or objects move in a coaxial fashion with regard to each other. Specifically, in order for the at least two elements and / or objects to be able to perform a telescopic movement, the shape and / or form of one of these objects may influence and / or restrict the shape and / or form of at least one other object, such as that one of the at least two objects must at least partially fit into the at least one other object, e.g. such as by being at least partially stackable, such as to allow for a space saving retracted position.

[0064] Thus, the cap, the insertion tool and the insertion sleeve being configured to perform a movement relative to the guide sleeve from a distal position to a proximal position in a telescopic fashion, may refer to a set-up in which the cap, the insertion tool, the insertion sleeve and the guide sleeve are at least partially stackable. As an example, the insertion tool may be formed such as to fit, at least partially, into the insertion sleeve, e.g. into the space enclosed within the insertion sleeve, wherein the insertion sleeve in turn may be formed such as to fit, at least partially, into the guide sleeve, e.g. into the space enclosed within the guide sleeve, wherein further the guide sleeve in turn may be formed such as to fit, at least partially, into the cap, i.e. into the space enclosed within the cap.

[0065] The elastic member and the profile member may be spaced apart from each other by one of a gap and a resisting member. Specifically, the resisting member may be physically connected to the profile member. As an example, the profile member and the resisting member may be formed integrally. The elastic member may for example be configured to engage, e.g. physically touch, the profile member at its free end. As an example, the elastic member, at its free end, may comprise at least one rounded surface. The rounded surface may specifically have at least one radius r. In particular, it may be that 0.5 mm < r < 2 mm. Specifically, it may be that 0.6 mm < r < 1.8 mm. More specifically, it may be that 0.7 mm < r < 1.5 mm. More specifically r may be 1 mm.

[0066] The elastic member from its free end to its fixed end may have a length L in a direction perpendicular to the insertion axis. In particular, it may be that 1 mm < L < 20 mm. Specifically, it may be that 1.5 mm < L < 10 mm. More specifically, it may be that 2 mm < L < 8 mm.

[0067] The friction pairing may comprise more than one elastic member configured for interacting with one profile member. Specifically, the friction pairing may comprise at least two elastic members, such as at least two elastic members configured for interacting with one profile member.

[0068] The at least two elastic members may be arranged such as to interact with the profile member on different sides of the profile member. For example, the at least two elastic members may be configured to interact with the profile member on opposing sides of the profile member, such as in a plier-like fashion.

[0069] The profile member may comprise at least one interacting surface configured for engaging with the at least one elastic member at least once during the movement from the distal position to the proximal position. In particular, the interacting surface may at least partially be sloped. As an example, in an arrangement where at least two elastic members are configured to interact with one profile member, the profile member may comprise more than one of such interaction surfaces.

[0070] The slope may have a gradient m, wherein the absolute value of m may be in the range of from 10% to 800 %. Specifically, the absolute value of m may be in the range of from 30% to 300 %. In particular, the gradient may be defined as m = Ay / Ax, or as m = Ax / Ay.

[0071] The at least one interacting surface may have a profile, such as a surface profile, at least partially comprising a form and / or shape selected from the group consisting of: a ramp, e.g. a fin and / or ramp having an increasing or decreasing gradient; a wave, e.g. a symmetrical subsequent rising and falling shape, such as a sine and / or cosine form; and a saw tooth, e.g. an asymmetric shape of subsequently arranged ramps having different gradients.

[0072] At least one of the insertion sleeve and the cap in conjunction with the guide sleeve may form more than one friction pairing. Specifically at least one of the insertion sleeve and the cap in conjunction with the guide sleeve may form at least two friction pairings. More specifically, at least one of the insertion sleeve and the cap in conjunction with the guide sleeve may form at least three friction pairings. For example, at least one of the insertion sleeve and the cap in conjunction with the guide sleeve may form at least four friction pairings. In particular, the more than one friction pairings may be equally arranged and spaced around the insertion axis. As an example, the profile member may be one continuous profile member surrounding the insertion axis.

[0073] In the friction pairing, the elastic member may for example be configured to exert a maximum force FK max onto the profile member, specifically in a direction perpendicular onto a surface of the profile member. As an example, the maximum force FK max may be more than or equal to 3 N. Specifically, the maximum force FK max may be in the range of from 3 N to 5 N.

[0074] The insertion device may further comprise at least one rail pairing configured for guiding the movement of the insertion sleeve relative to the guide sleeve, wherein the insertion sleeve may comprise one part of the rail pairing and wherein the guide sleeve may comprise the counterpart of the rail pairing.

[0075] The insertion sleeve may comprise the at least one profile member and the guide sleeve may comprise the at least one elastic member. As an example, the profile member may be connected to an outer surface of the insertion sleeve and the elastic member, specifically at its fixed end, may be connected to an inner surface of the guide sleeve. Specifically, the outer surface of the insertion sleeve may be a surface of the insertion sleeve facing the guide sleeve and the inner surface of the guide sleeve may be a surface of the guide sleeve facing the insertion sleeve. As an example, the profile member and the insertion sleeve may be integrally formed, such as in one piece, e.g. as a monolithic element. For example, the insertion sleeve and the profile member may be one injection molded piece. As an example, the elastic member and the guide sleeve may be integrally formed, such as in one piece, e.g. as a monolithic element. For example, the guide sleeve and the elastic member are one injection molded piece. Alternatively, the insertion sleeve may comprise the at least one elastic member, such that the elastic member may be arranged on the part of the rail pairing comprised by the insertion sleeve, and the guide sleeve may comprise the at least one profile member, such that the profile member may be arranged on the counterpart of the rail pairing comprised by the guide sleeve. As an example, the elastic member, specifically at its fixed end, may be connected to an outer surface of the insertion sleeve and the profile member may be connected to an inner surface of the guide sleeve. Specifically, the outer surface of the insertion sleeve may be a surface of the insertion sleeve facing the guide sleeve and the inner surface of the guide sleeve may be a surface of the guide sleeve facing the insertion sleeve. As an example, the elastic member and the insertion sleeve may be integrally formed, such as in one piece, e.g. as a monolithic element. For example, the insertion sleeve and the elastic member may be one injection molded piece. As an example, the profile member and the guide sleeve may be integrally formed, such as in one piece, e.g. as a monolithic element. For example, the guide sleeve and the profile member may be one injection molded piece.

[0076] One or both of the elastic member and the profile member may comprise at least one material having a friction coefficient p of 0.04 < p < 0.12. Specifically, p may be 0.06 < p < 0.08.

[0077] In particular, the at least one elastic member may comprise at least one polycarbonate, such as Makrolon®, specifically Makrolon® M204 LF. Other sliding-modified materials may also be feasible. Specifically, the at least one profile member may comprise at least one polycarbonate, such as Makrolon®, specifically Makrolon® M204 LF. Other sliding-modified materials may also be feasible. In particular, the elastic member and the profile member may be or may comprise one or more sliding modified material pairing for providing a predefined, repeatable and / or equally distributed friction characteristic.

[0078] The insertion device may further comprise the at least one insertion tool retractor and the at least one spring connected to the insertion tool retractor. In particular, as for example outlined above, the spring may be configured for driving the insertion tool retractor to move from its proximal position to its distal position. Specifically, the spring may be pretensioned and may be actuatable by releasing the insertion force applied to the cap and / or the insertion sleeve. As an example, the spring, by driving the insertion tool retractor from its proximal position to its distal position, may be configured to also drive the movement of the cap from its proximal position to its distal position.

[0079] As outlined above, the medical device may comprise at least one analyte sensor for detecting at least one analyte in a bodily fluid of the subject. As an example, the medical device may comprise the analyte sensor received in the sensor patch, e.g. as described in further detail below. Thus, the insertion device may be configured for receiving the sensor patch and for attaching the sensor patch to the skin site of the user. The insertion device may be configured for attaching and / or arranging the sensor patch to the skin site of the user, in particular simultaneously with the insertion of the insertion tool into the body tissue of the user. In particular, the insertion sleeve may comprise at least one receptacle for the sensor patch, e.g. located on the proximal end of the insertion sleeve, in which the sensor patch may be deposited before insertion.

[0080] In a further aspect of the present invention, an insertion system for inserting at least one insertable part of a medical device into a body tissue of a subject is disclosed. The insertion system comprises the insertion device as disclosed herein, specifically as described above or as further described below, and a medical device. For possible definitions and options of the insertion system, reference is made to the disclosure of the insertion device according to the present invention.

[0081] In particular, the medical device may comprise at least one analyte sensor for detecting at least one analyte in a bodily fluid of the subject. Specifically, the medical device may be or may comprise one or more of the medical devices as described herein, specifically as described above, e.g. with regard to the insertion device, or as further described below.

[0082] The medical device may further comprise at least one sensor patch. In particular, the sensor patch may be held in a receptacle of the insertion sleeve, in particular in a proximally positioned receptacle of the insertion sleeve. Thus, during insertion, the sensor patch may be configured to move together with the insertion sleeve and to be released from the insertion sleeve when the insertion sleeve is in its proximal position. The term “sensor patch” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an element configured for being attached to the skin site of the subject. In particular, the sensor patch may have a flat base, which is configured for being attached to the skin site of the subject. The sensor patch may comprise an electronics unit, which may be configured for being connected to the medical device, specifically to the analyte sensor. The electronics unit may have large dimensions compared to the analyte sensor and to the insertion tool. The diameter of the insertion tool may be as large as 1 mm while the sensor patch may extend for up to 2 to 4 cm. The sensor patch may comprise at least one adhesive means for being attached to the skin site of the subject. The sensor patch may remain attached to the skin site of the subject after the insertable part of the medical device, e.g. of the analyte sensor, has been inserted into the body tissue of the subject. The insertion tool may protrude through the sensor patch received in the insertion device, specifically in the insertion sleeve of the insertion device.

[0083] In particular, if the medical device comprises a sensor patch, the insertion of the insertable part of the medical device into the body tissue of the subject may be facilitated and more reliable. When the insertion system is applied to the skin, the skin typically bulges toward the interior of the insertion device. The short time delay between the insertion device, in particular the insertion tool, being in the proximal position and the insertion device, in particular the insertion tool, being moved back in its distal position may allow the application of pressure onto the bulged skin by the sensor patch. This may compensate the inward bulging of the skin as well as the indenting of the inward bulged skin by the insertion tool. Thus, the sliding of the insertion tool together with the insertable part of the medical device into the skin may be facilitated.

[0084] In a further aspect of the present invention, a method of inserting at least one insertable part of a medical device into a body tissue of a subject is disclosed. The method comprises using at least one insertion system as disclosed herein, specifically as described above or as further described below. Thus, for possible definitions and options, reference may be made to the disclosure of the insertion system and / or the insertion device according to the present invention.

[0085] The method comprises the following steps, which specifically me be performed in the given order. The method may comprise further method steps that are not listed.

[0086] The method comprises the following steps: a) inserting the medical device into the body tissue of the subj ect by applying an insertion force in a parallel direction of the insertion axis on one or both of the cap and the insertion sleeve of the insertion device thereby moving the cap, the insertion tool and the insertion sleeve relative to the guide sleeve from a distal position to a proximal position, wherein the insertion force is greater than the friction force provided by the friction pairing in response to the insertion force, wherein the friction force changes with the advancing of the movement of one or more of the cap and the insertion sleeve relative to the guide sleeve from the distal position to the proximal position; and b) retracting the insertion tool by relieving the insertion force applied to one or both of the cap and the insertion sleeve, thereby moving the insertion tool from its proximal position to its distal position, e.g. via the movement of one or both of the cap and the insertion sleeve from their respective proximal positions to their respective distal positions.

[0087] The movement of the cap, the insertion tool and the insertion sleeve from their respective distal positions to their respective proximal positions in step a) may be driven by an action of the subject, i.e. by the subject applying the insertion force on one or both of the cap and the insertion sleeve. The insertion force may be applied by the user and / or subject of the insertion device before and during the insertion of the at least one insertable part of the medical device into the body tissue of the subject. The insertion of the at least one insertable part of the medical device may be started by setting the guide sleeve, in particular the proximal end of the guide sleeve, in contact with the skin of the subject, specifically at an insertion site. Thus, step a) of the method may comprise applying the insertion device to the skin site of the subject, in particular applying the guide sleeve of the insertion device to the skin site of the subject.

[0088] Prior to insertion, the insertion sleeve may be in its distal position and may be at least partially enclosed by the guide sleeve in its distal position. The cap may be in contact to the insertion sleeve, specifically at the distal end of the insertion sleeve. Prior to insertion, the insertion tool, and optionally the insertion tool retractor, may be in its starting position and may be at least partially enclosed by the insertion sleeve. The starting position of the insertion tool, and optionally of the insertion tool retractor, may be at a proximal position relative to the insertion sleeve. As an example, the spring may be in between the insertion tool retractor and the insertion sleeve and the elastic member may be at full tension. The insertion sleeve and / or the cap are arranged relative to the guide sleeve, such that the elastic member and the profile member of the at least one friction pairing are spaced apart from each other, e.g. by one of a gap and a resisting member arranged between the elastic member and the profile member.

[0089] In order to insert at least the insertable part of the medical device into the body tissue, the arm of the user and / or subject exerts the insertion force onto the insertion device, specifically onto the cap and / or onto the insertion sleeve of the insertion device, for example by using one or more fingers or a palm of the hand, wherein the insertion force has to be higher than the friction force with which the at least one friction pairing acts against the force exerted by the user and / or subject. Depending on the profile of the profile member, the friction force may increase and / or decrease with the advancing of the movement from the distal position to the proximal position. This may specifically prevent any lifting and / or detaching movement of the insertion device away from the skin and thus any displacement of the insertion device during the insertion process. Furthermore, the change in the friction force, e.g. an increase of the friction force and / or a decrease of the friction force, during the advancing of the movement, may ensure a pre-tensioning of the skin, e.g. a constant pre-tensioning, by the guide sleeve always being in contact with the skin and forwarding the pressure onto the skin, which may further support an adequate penetration of the skin by the insertion needle, thereby ensuring a proper implantation of the insertable part of the medical device, i.e. of the analyte sensor. The movement may be stopped when the insertion device reaches its proximal position, e.g. when the proximal end of the cap and / or the insertion sleeve aligns with the proximal end of the guide sleeve.

[0090] The movement of the cap, the insertion tool and the insertion sleeve from their respective proximal positions to their respective distal positions in step b) may be initiated by a relieving action of the subject, i.e. by the subject removing the insertion force from one or both of the cap and the insertion sleeve. Specifically, step b) may comprise relieving the insertion force applied to the cap and / or the insertion sleeve. In particular, the movement of the cap together with the insertion tool, the insertion sleeve and optionally the insertion tool retractor from its proximal position to its distal position, specifically to its distal retraction position, may be initiated by a relieving action of the subject, e.g. by the subject removing the insertion force from the cap and / or the insertion sleeve. As an example, triggered by relieving the insertion force applied to the cap and / or to the insertion sleeve, the spring may force the insertion tool, optionally via the insertion tool retractor, and in consequence the cap into movement towards the distal position.

[0091] The devices, systems and methods according to the present invention provide a large number of advantages over known methods and devices. Specifically, the devices, systems and methods according to the present invention may allow for a specified, low scattering and reproducible insertion force, specifically within predefined limits, in particular due to the friction pairing formed by one of the insertion sleeve and the cap in conjunction with the guide sleeve. Specifically, a friction force scatter may be reduced to a minimum, while at the same time allowing for a reproducible friction force curve within predefined and specified limits. Furthermore, due to the friction force requiring a permanent force onto the insertion device during the insertion, a movement, e.g. a bouncing movement, of the insertion device during the insertion process may be effectively prevented. Thus, the devices, systems and methods according to the present invention, specifically due to the construction of the friction pairing, may ensure successful application of the analyte sensor, and thus also of the optional sensor patch, into the body tissue. Furthermore, the devices, systems and methods according to the present invention, specifically due to the construction of the friction pairing, may prevent plastic deformation of the insertion device and / or its components before, e.g. during storage times, and during the insertion.

[0092] Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

[0093] Embodiment 1. An insertion device for inserting at least one insertable part of a medical device into a body tissue of a subject along an insertion axis, the insertion device comprising an insertion tool, a cap, an insertion sleeve and a guide sleeve configured for guiding the insertion sleeve therein, wherein the insertion sleeve and / or the cap in conjunction with the guide sleeve form at least one friction pairing comprising at least one elastic member and at least one profile member, wherein at least one of the cap and the insertion sleeve comprises one of the at least one elastic member and the at least one profile member of the friction pairing and wherein the guide sleeve comprises the at least one other of the at least one elastic member and the at least one profile member of the friction pairing, wherein, for inserting the at least one insertable part of the medical device, the cap, the insertion tool and the insertion sleeve are configured to perform a movement relative to the guide sleeve from a distal position to a proximal position in a telescopic fashion, wherein the friction pairing, in response to an insertion force acting on one or more of the cap and the insertion sleeve in a direction parallel to the insertion axis, is configured to provide a friction force changing with advancing of the movement of one or more of the cap and the insertion sleeve from the distal position to the proximal position, wherein in the distal position, the elastic member and the profile member of the at least one friction pairing are spaced apart from each other.

[0094] Embodiment 2. The insertion device according to the preceding embodiment, wherein the elastic member and the profile member are spaced apart from each other by one of a gap and a resisting member, wherein specifically the resisting member is physically connected to the profile member, e.g. the profile member and the resisting member are formed integrally.

[0095] Embodiment s. The insertion device according to any one of the preceding embodiments, wherein the elastic member is configured to engage the profile member at its free end.

[0096] Embodiment 4. The insertion device according to the preceding embodiment, wherein the elastic member, at its free end, comprises at least one rounded surface. Embodiment 5. The insertion device according to the preceding embodiment, wherein the rounded surface has at least one radius r, wherein 0.5 mm < r < 2 mm, specifically 0.6 mm < r < 1.8 mm, more specifically 0.7 mm < r < 1.5 mm, more specifically r may be 1 mm.

[0097] Embodiment 6. The insertion device according to any one of the preceding embodiment, wherein the elastic member from its free end to its fixed end has a length L in a direction perpendicular to the insertion axis, wherein 1 mm < L < 20 mm, specifically 1.5 mm < L < 10 mm, more specifically 2 mm < L < 8 mm.

[0098] Embodiment 7. The insertion device according to any one of the preceding embodiments, wherein the friction pairing comprises more than one elastic member, specifically at least two elastic members, such as at least two elastic members configured for interacting with one profile member.

[0099] Embodiment 8. The insertion device according to the preceding embodiment, wherein the at least two elastic members are arranged such as to interact with the profile member on different sides of the profile member, e.g. on opposing sides of the profile member, such as in a plier-like fashion.

[0100] Embodiment 9. The insertion device according to any one of the preceding embodiments, wherein the profile member comprises at least one interacting surface configured for engaging with the at least one elastic member at least once during the movement from the distal position to the proximal position, wherein the interacting surface is at least partially sloped.

[0101] Embodiment 10. The insertion device according to the preceding embodiment, wherein the slope has a gradient m, wherein the absolute value of m is in the range of from 10% to 800 %, specifically from 30% to 300 %.

[0102] Embodiment 11. The insertion device according to any one of the two preceding embodiments, wherein the at least one interacting surface has a profile at least partially comprising a form and / or shape selected from the group consisting of: a ramp, e.g. a fin and / or ramp having an increasing or decreasing gradient; a wave, e.g. a symmetrical subsequent rising and falling shape, such as a sine and / or cosine form; and a saw tooth, e.g. an asymmetric shape of subsequently arranged ramps having different gradients. Embodiment 12. The insertion device according to any one of the preceding embodiments, wherein at least one of the insertion sleeve and the cap in conjunction with the guide sleeve form more than one friction pairing, specifically at least two friction pairings, more specifically at least three friction pairings, e.g. at least four friction pairings.

[0103] Embodiment 13. The insertion device according to the preceding embodiment, wherein the more than one friction pairings are equally arranged and spaced around the insertion axis.

[0104] Embodiment 14. The insertion device according to the preceding embodiment, wherein the profile member is one continuous profile member surrounding the insertion axis.

[0105] Embodiment 15. The insertion device according to any one of the preceding embodiments, wherein in the friction pairing, the elastic member is configured to exert a maximum force FK max onto the profile member, specifically in a direction perpendicular onto a surface of the profile member, of more than or equal to 3 N, specifically in the range of from 3 N to 5 N.

[0106] Embodiment 16. The insertion device according to any one of the preceding embodiments, further comprising at least one rail pairing configured for guiding the movement of the insertion sleeve relative to the guide sleeve, wherein the insertion sleeve comprises one part of the rail pairing and wherein the guide sleeve comprises the counterpart of the rail pairing.

[0107] Embodiment 17. The insertion device according to any one of the preceding embodiments, wherein the insertion sleeve comprises the at least one profile member and wherein the guide sleeve comprises the at least one elastic member.

[0108] Embodiment 18. The insertion device according to the preceding embodiment, wherein the profile member is connected to an outer surface of the insertion sleeve and the elastic member, specifically at its fixed end, is connected to an inner surface of the guide sleeve, specifically wherein the outer surface of the insertion sleeve is a surface of the insertion sleeve facing the guide sleeve and wherein the inner surface of the guide sleeve is a surface of the guide sleeve facing the insertion sleeve.

[0109] Embodiment 19. The insertion device according to any one of the two preceding embodiments, wherein the profile member and the insertion sleeve are integrally formed, such as in one piece, e.g. as a monolithic element, for example the insertion sleeve and the profile member are one injection molded piece.

[0110] Embodiment 20. The insertion device according to any one of the three preceding embodiments, wherein the elastic member and the guide sleeve are integrally formed, such as in one piece, e.g. as a monolithic element, for example the guide sleeve and the elastic member are one injection molded piece.

[0111] Embodiment 21. The insertion device according to embodiment 16, wherein the insertion sleeve comprises the at least one elastic member, such that the elastic member is arranged on the part of the rail pairing comprised by the insertion sleeve, and wherein the guide sleeve comprises the at least one profile member, such that the profile member is arranged on the counterpart of the rail pairing comprised by the guide sleeve.

[0112] Embodiment 22. The insertion device according to the preceding embodiment, wherein the elastic member, specifically at its fixed end, is connected to an outer surface of the insertion sleeve and the profile member is connected to an inner surface of the guide sleeve, specifically wherein the outer surface of the insertion sleeve is a surface of the insertion sleeve facing the guide sleeve and wherein the inner surface of the guide sleeve is a surface of the guide sleeve facing the insertion sleeve.

[0113] Embodiment 23. The insertion device according to any one of the two preceding embodiments, wherein the elastic member and the insertion sleeve are integrally formed, such as in one piece, e.g. as a monolithic element, for example the insertion sleeve and the elastic member are one injection molded piece.

[0114] Embodiment 24. The insertion device according to any one of the three preceding embodiments, wherein the profile member and the guide sleeve are integrally formed, such as in one piece, e.g. as a monolithic element, for example the guide sleeve and the profile member are one injection molded piece.

[0115] Embodiment 25. The insertion device according to any one of the preceding embodiments, wherein one or both of the elastic member and the profile member comprises at least one material having a friction coefficient p of 0.04 < p < 0.12, specifically 0.06 < p < 0.08. Embodiment 26. The insertion device according to any one of the preceding embodiments, wherein the at least one elastic member comprises at least one polycarbonate, such as Makrolon®, specifically Makrolon® M204 LF.

[0116] Embodiment 27. The insertion device according to any one of the preceding embodiments, wherein the at least one profile member comprises at least one polycarbonate, such as Makrolon®, specifically Makrolon® M204 LF.

[0117] Embodiment 28. The insertion device according to any one of the preceding embodiments, further comprising at least one insertion tool retractor and at least one spring connected to the insertion tool retractor, wherein the spring is configured for driving the insertion tool retractor to move from its proximal position to its distal position.

[0118] Embodiment 29. The insertion device according to the preceding embodiment, wherein the spring is pretensioned and is actuatable by releasing the insertion force applied to the cap and / or the insertion sleeve.

[0119] Embodiment 30. The insertion device according to any one of the two preceding embodiments, wherein the spring by driving the insertion tool retractor from its proximal position to its distal position is configured to also drive the movement of the cap from its proximal position to its distal position.

[0120] Embodiment 31. The insertion device according to any one of the preceding embodiments, wherein the cap, when being in its proximal position, aligns with a proximal end of the guide sleeve.

[0121] Embodiment 32. The insertion device according to any one of the preceding embodiments, wherein the medical device comprises at least one analyte sensor for detecting at least one analyte in a bodily fluid of the subject.

[0122] Embodiment 33. An insertion system for inserting at least one insertable part of a medical device into a body tissue of a subject comprising the insertion device according to any one of the preceding embodiments and the medical device.

[0123] Embodiment 34. The insertion system according to the preceding embodiment, wherein the medical device, specifically the at least one analyte sensor for detecting at least one analyte in a bodily fluid of the subject, comprises a sensor patch. Embodiment 35. The insertion system according to any one of the two preceding embodiments, wherein the sensor patch comprises a flat base that is configured for being attached to a skin site of the subject.

[0124] Embodiment 36. A method of inserting at least one insertable part of a medical device into a body tissue of a subject by using at least one insertion system according to any one of the preceding embodiments referring to an insertion system, the method comprising: a) inserting the medical device into the body tissue of the subj ect by applying an insertion force in a parallel direction of the insertion axis on one or both of the cap and the insertion sleeve of the insertion device thereby moving the cap, the insertion tool and the insertion sleeve relative to the guide sleeve from a distal position to a proximal position, wherein the insertion force is greater than the friction force provided by the friction pairing in response to the insertion force, wherein the friction force changes with the advancing of the movement of one or more of the cap and the insertion sleeve relative to the guide sleeve from the distal position to the proximal position; and b) retracting the insertion tool by relieving the insertion force applied to one or both of the cap and the insertion sleeve, thereby moving the insertion tool from its proximal position to its distal position, e.g. via the movement of one or both of the cap and the insertion sleeve from their respective proximal positions to their respective distal positions.

[0125] Embodiment 37. The method according to the preceding embodiment, wherein the movement of the cap, the insertion tool and the insertion sleeve from their respective distal positions to their respective proximal positions in step a) is driven by an action of the subject, i.e. by the subject applying the insertion force on one or both of the cap and the insertion sleeve.

[0126] Embodiment 38. The method according to any one of the two preceding embodiments, wherein the movement of the cap, the insertion tool and the insertion sleeve from their respective proximal positions to their respective distal positions in step b) is initiated by a relieving action of the subject, i.e. by the subject removing the insertion force from one or both of the cap and the insertion sleeve.

[0127] Short description of the Figures Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.

[0128] In the Figures:

[0129] Figure 1 shows an embodiment of an insertion device in a sectional view;

[0130] Figures la to Id show enlarged details of the insertion device of Figure 1;

[0131] Figures le and If show alternative embodiments of a profile member in sectional views;

[0132] Figure 2 shows another embodiment of an insertion device in a sectional view;

[0133] Figure 2a shows an enlarged detail of the insertion device of Figure 2;

[0134] Figures 3 a to 3 c show details of another embodiment of an insertion device in sectional views (Figures 3a and 3b) and in a top plane view (Figure 3 c);

[0135] Figure 4 shows another embodiment of an insertion device in a perspective view;

[0136] Figures 4a to 4c show enlarged details of the insertion device of Figure 4;

[0137] Figure 5 shows another embodiment of an insertion device in a sectional view;

[0138] Figure 5a shows an enlarged detail of the insertion device of Figure 5;

[0139] Figure 5b shows the insertion device of Figure 5 in a top plane view;

[0140] Figure 6 shows a graph of the friction force provided by the friction pairing of the insertion device of Figure 5; and Figure 7 shows a method of inserting at least one insertable part of a medical device into a body tissue of a subject by using at least one embodiment of an insertion system comprising an embodiment of an insertion device.

[0141] Detailed description of the embodiments

[0142] Figures 1, 2, 3a to 3c, 4 and 5 illustrate different embodiment of an insertion device 110, while Figure 7 illustrates a method of inserting at least one insertable part of a medical device 112 into a body tissue 114 of a subject by using at least one embodiment of an insertion system 111 comprising an embodiment of the insertion device 110. The insertion system 111 comprises the insertion device 110 and the medical device 112. The figures are described together.

[0143] The insertion device 110 is configured for inserting the at least one insertable part of the medical device 112 into the body tissue 114 of the subject along an insertion axis 116. The insertion device 110 comprises an insertion tool 117. Optionally, the insertion device 110 comprises one or more of an insertion tool retractor 118 and a spring 120. The insertion device 110 further comprises a cap 122, an insertion sleeve 124 and a guide sleeve 126 configured for guiding the insertion sleeve 124 therein. The insertion sleeve 124 and / or the cap 122 in conjunction with the guide sleeve 126 form at least one friction pairing 128 comprising at least one elastic member 130 and at least one profile member 132. For the purpose of better visibility, the insertion tool 117 and the cap 122 are not illustrated in Figures 1 to 5.

[0144] As an example, the friction pairing 128 may comprise more than one elastic member 130, specifically at least two elastic members 130, such as at least two elastic members 130 configured for interacting with one profile member 132. In particular, the at least two elastic members 130 may be arranged such as to interact with the profile member 132 on different sides of the profile member 132, e.g. on opposing sides of the profile member 132, such as in a plier-like fashion. Such as set-up is exemplarily illustrated in Figures 3a to 3c.

[0145] At least one of the cap 122 and the insertion sleeve 124 comprises one of the at least one elastic member 130 and the at least one profile member 132 of the friction pairing 128 and the guide sleeve 126 comprises the at least one other of the at least one elastic member 130 and the at least one profile member 132 of the friction pairing 128. As an example, the insertion sleeve 124 may comprise the at least one profile member 132 and the guide sleeve 126 may comprise the at least one elastic member 130. This set-up is exemplarily illustrated in the embodiments shown in Figures 1, la to If, 2, 2a, 3a to 3c, 4 and 4a to 4c. Alternatively, the insertion sleeve 124 may comprise the at least one elastic member 132 and the guide sleeve 126 may comprise the at least one profile member 130. This set-up is exemplarily illustrated in the embodiment shown in Figures 5, 5a and 5b.

[0146] As an example, the at least one of the insertion sleeve 124 and the cap 122 in conjunction with the guide sleeve 126 may form more than one friction pairing 128, specifically at least two friction pairings 128. In particular, they may form at least four friction pairings 128. For example, the more than one friction pairings 128 may be ranged and / or spaced equally around the insertion axis 116.

[0147] For inserting the at least one insertable part of the medical device 112, the cap 122, the insertion tool 117 and the insertion sleeve 124 are configured to perform a movement relative to the guide sleeve 126 from a distal position 134 to a proximal position 136 in a telescopic fashion. In Figures la, Id, le, If, 2a, 3 a 4c, 5 a and 7, the movement direction 138 of the cap 122, the insertion tool 117 and the insertion sleeve 124 from the distal position 134 to the proximal position 136 relative to the guide sleeve 126 is exemplarily illustrated by arrow 138. The same arrow 138 also indicates the direction parallel to the insertion axis 116 in which an insertion force 140 is acting on one or more of the cap 122 and the insertion sleeve 124 in order to drive the insertion of the insertable part of the medical device 112 into the body tissue 114. The friction pairing 128, in response to the insertion force 140 acting on one or more of the cap 122 and the insertion sleeve 124 in the direction parallel to the insertion axis 116, is configured to provide a friction force changing with advancing of the movement 138 of one or more of the cap 122 and the insertion sleeve 124 from the distal position 134 to the proximal position 136. The friction force at least partially acts parallel to the insertion axis 116 in a counter direction to the movement 138 and the insertion force 140.

[0148] The friction force may result from a force with which the elastic member 130 presses against the profile member 132, or vice versa. As an example, the force with which the elastic member 130 presses against the profile member 132 may be a clamping force, specifically in case two elastic members 130 act on one profile member 132. In Figure 3b, the acting direction of the friction forces are indicated by arrows FR and the acting direction of the clamping forces are indicated by arrows FK.

[0149] In the distal position 134, i.e. in the insertion device’s 110 distal position 134, e.g. when all the part of the insertion device 110 are in their respective distal positions 134, the elastic member 130 and the profile member 132 of the at least one friction pairing 128 are spaced apart from each other. This set-up is exemplarily illustrated in Figures 1, la, lb, 2, 2a, 3a, 4, 4a, 4c and 5. As an example, the elastic member 130 and the profile member 132 may be spaced apart from each other by one of a gap 142 and a resisting member 144. Specifically, the resisting member 144 may be physically connected to the profile member 132. In particular, the profile member 132 and the resisting member 144 may even be formed integrally, as exemplarily illustrated in Figures 2, 2a 5 and 5a.

[0150] In the friction pairing 128 and specifically during the movement from the distal position 134 to the proximal position 136, the elastic member 130 may be configured to engage the profile member 132 at its free end 146. The elastic member 130 from its free end 146 to its fixed end, e.g. to the end where the elastic member 130 is fixed to one of the cap 122, the insertion sleeve 124 and the guide sleeve 126, may have a length L 147 in a direction perpendicular to the insertion axis 116, wherein as an example L may be 1 mm < L < 20 mm. The elastic member 130, specifically at its free end 146, may comprise at least one rounded surface. This rounded surface may specifically be beneficial for defining a line of contact 148 between the elastic member 130 and the profile member 132 and thus, for tailoring a profile 150 of the profile member 132 in order to result in a desired friction force during the progress of the movement 138. Thus, depending on the desired friction force, the profile 150 may have different shapes. As an example, the profile 150 may comprise the shape of a ramp 152, e.g. a fin having an increasing gradient, as exemplarily illustrated in Figure Id, such as to gradually increase the friction force with advancing movement 138. Additionally or alternatively, the profile 150 may comprise the shape of a decreasing ramp 152 in order to include a decrease of the friction force with the advancing movement 138, e.g. to temporarily speed up the movement progression, i.e. at constant insertion force 140. This shape is exemplarily illustrated in Figure Id. Additionally or alternatively, the profile 150 may comprise the shape of a wave 154, as exemplarily illustrated in Figure le, and / or of a saw tooth 156, as exemplarily illustrated in Figure If. However, other shapes of the profile 150 are also possible.

[0151] Further, the insertion device 110 may comprise at least one rail pairing 158 configured for guiding the movement 138 of the insertion sleeve 124 relative to the guide sleeve 126, wherein the insertion sleeve 124 may comprise one part of the rail pairing and wherein the guide sleeve 126 may comprise the counterpart of the rail pairing 158. As exemplarily illustrated in Figures 5, 5a and 5b, the insertion sleeve 124 may comprise the at least one elastic member 130 and the guide sleeve 126 may comprise the at least one profile member 132, such that the elastic member 130 is arranged on the part of the rail pairing 158 comprised by the insertion sleeve 124 and the profile member 132 is arranged on the counterpart of the rail pairing 158 comprised by the guide sleeve 126. As an example, in order to insert the at least one insertable part of the medical device 112 into the body tissue 114 of the subject, the subject and / or user may have to apply the insertion force 140 onto the cap 122 and / or onto the insertion sleeve 124. This force application may in turn lead the elastic member 130, specifically after having overcome the gap 144 or the resisting member 144, to engage the profile member 132. During the advancing movement 138, the elastic member 130 may have to deform and / or deflect due to the profile member 132, resulting in a friction force, e.g. acting in a direction opposite to the insertion force 140. A graph of a measured friction force changing over and / or with the advancing of the movement 138 from the distal position 134 to the proximal position 136 is exemplarily illustrated in Figure 6. In the graph, the x-axis 160 shows the moving progress, e.g. the moving distance in millimeter [mm], from the distal position 134 to the proximal position 136, while the y- axis 162 shows the friction force in Newton [N], The graph illustrates measurement results of the friction force taken from a prototype of the insertion device 110 as illustrated in Figures 5, 5a and 5b, in eight movements 138. As can be seen from the graph, the insertion device 110 allows for a specified, low scattering and reproducible insertion force, specifically within predefined limits, in particular due to the friction pairing 128. In detail, in the first movement 138, the maximum friction force was 23,98 N, in the second movement 138, the maximum friction force was 24,16 N, in the third movement 138, the maximum friction force was 24,50 N, in the fourth movement 138, the maximum friction force was 24,09 N, in the fifth movement 138, the maximum friction force was 24,26 N, in the sixth movement 138, the maximum friction force was 24,19 N, in the sevenths movement 138, the maximum friction force was 24,03 N, in the eights movement 138, the maximum friction force was 24,23 N.

[0152] The medical device 112 may comprise at least one analyte sensor 164 for detecting at least one analyte in a bodily fluid of the subject and at least one sensor patch 166 comprising a flat base 168 configured for being attached to a skin site 170 of the subject.

[0153] The transition from the setup on the left to the setup in the middle of Figure 7 and the transition of the setup of the middle to the setup on the right of Figure 7 exemplarily illustrates the method. The method of inserting the at least one insertable part of the medical device 112 into the body tissue 114 of the subject by using the at least one insertion system 111 comprises the following steps: a) (denoted by reference number 172) inserting the medical device 112 into the body tissue 114 of the subject by applying an insertion force in a parallel direction of the insertion axis 116 on one or both of the cap 122 and the insertion sleeve 124 of the insertion device 110 thereby moving the cap 122, the insertion tool 117 and the insertion sleeve 124 relative to the guide sleeve 126 from a distal position 134 to a proximal position 136, wherein the insertion force 140 is greater than the friction force provided by the friction pairing 128 in response to the insertion force 140, wherein the friction force changes with the advancing of the movement 138 of one or more of the cap 122 and the insertion sleeve 124 relative to the guide sleeve 136 from the distal position 134 to the proximal position 136; and b) (denoted by reference number 174) retracting the insertion tool 117 by relieving the insertion force 140 applied to one or both of the cap 122 and the insertion sleeve 124, thereby moving the insertion tool 117 from its proximal position 136 to its distal position 134, e.g. via the movement of one or both of the cap 122 and the insertion sleeve 124 from their respective proximal positions 136 to their respective distal positions 134. In particular, in the setup on the right of Figure 3, the insertion tool 117 may be in its distal position 134, specifically in its distal retraction position.

[0154] List of reference numbers insertion device insertion system medical device body tissue insertion axis insertion tool insertion tool retractor spring cap insertion sleeve guide sleeve friction pairing elastic member profile member distal position proximal position movement direction acting direction of insertion force gap resisting member free end length L line of contact profile ramp shape wave shape saw tooth shape rail pairing x-axis y-axis analyte sensor sensor patch flat base skin site step a) step b)

Claims

Claims1. An insertion device (110) for inserting at least one insertable part of a medical device (112) into a body tissue (114) of a subject along an insertion axis (116), the insertion device (110) comprising an insertion tool (117), a cap (122), an insertion sleeve (124) and a guide sleeve (126) configured for guiding the insertion sleeve (124) therein, wherein the insertion sleeve (124) and / or the cap (122) in conjunction with the guide sleeve (126) form at least one friction pairing (128) comprising at least one elastic member (130) and at least one profile member (132), wherein at least one of the cap (122) and the insertion sleeve (124) comprises one of the at least one elastic member (130) and the at least one profile member (132) of the friction pairing (128) and wherein the guide sleeve (126) comprises the at least one other of the at least one elastic member (130) and the at least one profile member (132) of the friction pairing (128), wherein, for inserting the at least one insertable part of the medical device (112), the cap (122), the insertion tool (117) and the insertion sleeve (124) are configured to perform a movement (138) relative to the guide sleeve (126) from a distal position (134) to a proximal position (136) in a telescopic fashion, wherein the friction pairing (128), in response to an insertion force (140) acting on one or more of the cap (122) and the insertion sleeve (124) in a direction parallel to the insertion axis (116), is configured to provide a friction force changing with advancing of the movement (138) of one or more of the cap (122) and the insertion sleeve (124) from the distal position (134) to the proximal position (136), wherein in the distal position (136), the elastic member (130) and the profile member (132) of the at least one friction pairing (128) are spaced apart from each other, wherein one or both of the elastic member and the profile member comprises at least one material having a friction coefficient p of 0.04 < p < 0.12, specifically 0.06 < p < 0.08.

2. The insertion device (110) according to the preceding claim, wherein the elastic member (130) and the profile member (132) are spaced apart from each other by one of a gap (142) and a resisting member (144).

3. The insertion device (110) according to any one of the preceding claims, wherein the elastic member (130) is configured to engage the profile member (132) at its free end (146), wherein the elastic member (130), at its free end (146), comprises at least one rounded surface, wherein the rounded surface has at least one radius r, wherein 0.5 mm < r < 2 mm.

4. The insertion device (110) according to any one of the preceding claims, wherein the friction pairing (128) comprises more than one elastic member (130), wherein the at least two elastic members (130) are arranged such as to interact with the profile member (132) on different sides of the profile member (132).

5. The insertion device (110) according to any one of the preceding claims, wherein the profile member (132) comprises at least one interacting surface configured for engaging with the at least one elastic member (130) at least once during the movement (138) from the distal position (134) to the proximal position (136), wherein the interacting surface is at least partially sloped, wherein the at least one interacting surface has a profile (150) at least partially comprising a form and / or shape selected from the group consisting of: a ramp (152); a wave (154); and a saw tooth (156).

6. The insertion device (110) according to any one of the preceding claims, wherein at least one of the insertion sleeve (124) and the cap (122) in conjunction with the guide sleeve (126) form more than one friction pairing (128), wherein the more than one friction pairings (128) are equally arranged and spaced around the insertion axis (116).

7. The insertion device (110) according to any one of the preceding claims, further comprising at least one rail pairing (158) configured for guiding the movement (138) of the insertion sleeve (124) relative to the guide sleeve (126), wherein the insertion sleeve (124) comprises one part of the rail pairing (158) and wherein the guide sleeve (126) comprises the counterpart of the rail pairing (158).

8. The insertion device (110) according to any one of the preceding claims, wherein the insertion sleeve (124) comprises the at least one profile member (132) and wherein the guide sleeve (126) comprises the at least one elastic member (130).

9. The insertion device (110) according to claim 7, wherein the insertion sleeve (124) comprises the at least one elastic member (130), such that the elastic member (130) is arranged on the part of the rail pairing (158) comprised by the insertion sleeve (124),and wherein the guide sleeve (126) comprises the at least one profile member (132), such that the profile member (132) is arranged on the counterpart of the rail pairing (158) comprised by the guide sleeve (126).

10. The insertion device (110) according to any one of the preceding claims, wherein the at least one elastic member and / or the profile member comprises at least one polycarbonate.

11. The insertion device (110) according to any one of the preceding claims, further comprising at least one insertion tool retractor (118) and at least one spring (120) connected to the insertion tool retractor (118), wherein the spring (120) is configured for driving the insertion tool retractor (118) to move from its proximal position (136) to its distal position (134).

12. An insertion system (111) for inserting at least one insertable part of a medical device (112) into a body tissue (114) of a subject comprising the insertion device (110) according to any one of the preceding claims and the medical device (112).

13. The insertion system according to the preceding claim, wherein the medical device (112) comprises a sensor patch (166).

14. A method of inserting at least one insertable part of a medical device (112) into a body tissue (114) of a subject by using at least one insertion system (111) according to any one of the preceding claims referring to an insertion system (111), the method comprising: a) inserting the medical device (112) into the body tissue of the subject by applying an insertion force (140) in a parallel direction of the insertion axis (116) on one or both of the cap (122) and the insertion sleeve (124) of the insertion device (110) thereby moving the cap (122), the insertion tool (117) and the insertion sleeve (124) relative to the guide sleeve (126) from a distal position (134) to a proximal position (136), wherein the insertion force (14) is greater than the friction force provided by the friction pairing (128) in response to the insertion force (140), wherein the friction force changes with the advancing of the movement (138) of one or more of the cap (122) and the insertion sleeve (124) relative to the guide sleeve (126) from the distal position (134) to the proximal position (136); andb) retracting the insertion tool (117) by relieving the insertion force (140) applied to one or both of the cap (122) and the insertion sleeve (124), thereby moving the insertion tool (117) from its proximal position (136) to its distal position (134).

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