medical devices

Abstract

A medical device is provided that includes a flexible electrode array having a bend radius of about 2 mm or less and a fluidic component, the fluidic component being fluidically actuatable to cause the fluidic component to change configuration, wherein the fluidic component and the flexible electrode array are configured such that a change in configuration of the fluidic component causes a change in configuration of the flexible electrode array.

Description

[Technical Field]

[0001] The present invention relates to medical devices having electrode arrays, and is particularly relevant to implantable devices that interact with biological tissues, such as the nervous system, for purposes such as recording cellular activity for scientific or diagnostic purposes, electrical stimulation, pain management, rehabilitation, and brain-machine interfaces. [Background technology]

[0002] Various medical devices can incorporate electrode arrays for either actively stimulating tissue or passively sensing (or a combination of the two). In recent years, implantable bioelectronic devices for treating and diagnosing disease have emerged as a key component of modern healthcare. When used to treat chronic disorders, implantable bioelectronic devices utilize electrical pulses to, for example, restore the physiological function of organs (as in the case of cardiac pacemakers and cochlear implants) or alleviate the chronic side effects of neurodegenerative syndromes (as in the case of deep brain stimulation (DBS) to stop tremors in Parkinson's disease). In addition to this, implantable bioelectronic devices are being used clinically for acute (up to 3 weeks) recording / mapping of neural activity in patients undergoing surgical brain resection of epileptogenic tissue.

[0003] However, the risk and cost of surgery to implant devices remains a limiting factor.

[0004] As a specific example, clinically available spinal cord stimulators (SCS) are used for pain management. To date, SCS devices have primarily been used for chronic pain management caused by failed back surgery syndrome and angina, among others. Such devices are implanted in the epidural space between the spinal cord and the vertebrae. They function by generating a local electric field that disrupts the transmission of neural signals from their source to their location in the brain.

[0005] Commercially available stimulation devices come in two types: linear and paddle designs. Linear arrays of electrodes (e.g., electrodes arranged sequentially on a single wire) can be implanted percutaneously through a needle in a simple and cost-effective procedure. Unfortunately, the advantage of easy implantation of this type of device is countered by both the very limited spatial resolution and lack of anatomical targeting capabilities that these thin-wire devices can offer. In contrast, paddles are millimeters thick and present electrodes, e.g., in rows, over a wider "paddle-shaped" area than single-wire devices, thus covering a larger surface area of ​​the spinal cord and providing a more specific and effective region for spinal cord electrical stimulation. However, implantation of larger paddle designs cannot be performed as simply and therefore requires a risky and expensive surgical procedure under general anesthesia.

[0006] While inflatable devices are known, they often suffer from several drawbacks. In particular, they may require significant space to deploy from an uninflated to an inflated state and / or may have undesirable side effects due to the device's expansion caused by the inflation process. Packaging for inflatable devices is also challenging, as the implant must be flexible enough to be rolled or folded into a compressed state small enough for percutaneous insertion. In contrast, clinically available devices such as spinal cord stimulators and electrocorticography arrays, as well as other proposed inflatable devices, have components such as thick metal electrodes or silicon tips that are too rigid to bend elastically over a sufficiently small radius.

[0007] Therefore, existing options for such medical devices are unsatisfactory.The present invention aims to at least partially address this problem. Summary of the Invention

[0008] A first aspect of the present invention provides a medical device comprising a flexible electrode array having a bend radius of about 2 mm or less and a fluidic component, the fluidic component being fluidically actuatable to cause the fluidic component to change configuration, wherein the fluidic component and the flexible electrode array are configured such that a change in configuration of the fluidic component causes a change in configuration of the flexible electrode array.

[0009] The electrode array of the above embodiment is highly flexible, with a bend radius of 2 mm or less, preferably 1.5 mm or less, and more preferably 1 mm or less. The bend radius, measured relative to the inner curvature, is the minimum radius that can be bent in at least one direction without damaging the component (in this case, the electrode array). As defined herein, bend radius refers to elastic deformation, as opposed to plastic deformation, such that an electrode array bent under an applied force to a radius greater than the minimum bend radius will at least partially return to its original shape upon removal of the applied force. In other words, the electrode array of the device of this embodiment can be bent to a 2 mm inner curvature, for example, by rolling when the device is being positioned for insertion into a patient, and subsequently deployed (e.g., unfolded) into an expanded, less bent configuration (e.g., a substantially flat configuration) and still function exactly as it did before being bent.

[0010] Preferably, the flexible electrode array has a bend radius of about 1.5 mm or less, more preferably about 1 mm or less, more preferably about 0.5 mm or less. The lower bend radius of the flexible electrode may allow the electrode array to be rolled into a tighter (and therefore thinner) cylindrical structure for deployment, while still retaining the functionality of the electrode array when the device is deployed by changing the configuration of the fluidic components.

[0011] The device can have a proximal section and a distal section, with the flexible electrode array and fluidic components disposed in the distal section. The distal section can have a bend radius in a first direction of about 2 mm or less (preferably smaller, e.g., 1.5 mm, 1 mm, or 0.5 mm, or less). For example, when implanted in a patient, it is generally the distal section of the device that must unfold in order for the electrode array to be positioned to perform its function. Thus, it may be the distal section that changes configuration upon actuation of the fluidic components. Other portions of the device, such as connectors to external components, such as tubing and wires, that connect the device to additional devices, such as an implanted pulse generator, and which may (or may need to) be rigid, can be disposed in the proximal section and therefore do not affect the distal section's ability to change configuration upon fluidic actuation.

[0012] In certain configurations, the medical device, particularly the distal section of the device, can have different properties in different directions. For example, the distal section can have a bend radius in a second direction orthogonal to a first direction that is larger than the bend radius in the first direction. This can apply to the entire distal section or to a specific portion of the distal section (such as a flexible electrode array). Such a change in properties can take the form of, for example, a device that is relatively stiff or inelastic along the insertion axis, yet still sufficiently flexible in an orthogonal direction, to aid in implant positioning so that the device can be rolled or compressed to allow implantation through a small incision.

[0013] In certain embodiments, the medical device is elongated, and the first direction is substantially perpendicular to the longitudinal axis of the device. This allows the flexible electrode array and / or distal section to be packaged to reduce the thickness of the device (e.g., to pass through a small incision, opening, lumen, or catheter during deployment) and then deployed to a larger configuration by fluid actuation when in the desired location. In many cases, it is desirable to reduce the thickness dimension of the device to allow deployment through the smallest possible gap, but changing or reducing the length dimension of the device is not critical because it does not affect the size of the required incision, opening, lumen, or catheter.

[0014] In certain embodiments, the device has a removable support element. The removable support element can provide rigidity to the device in one or more directions to aid in deployment of the device. For example, the removable support element can be a rigid element that extends along some or all of the longitudinal extent of the device to maintain rigidity of the device during deployment (e.g., by preventing "crumpling" of the device as it is pushed into the patient).

[0015] In certain embodiments, the device is configured such that when the removable support element is removed, the distal section has a bend radius of about 2 mm or less (preferably less, e.g., 1.5 mm, 1 mm, 0.5 mm, etc.) in each of the first and second directions. Thus, the removable support element may provide temporary or removable support or rigidity to the device, which can then be removed when that support is no longer needed.

[0016] A further aspect of the present invention provides a medical device comprising a flexible electrode array and a fluidic component, the fluidic component being fluidly actuatable to cause the fluidic component to change configuration, the fluidic component and the flexible electrode array being configured such that a change in configuration of the fluidic component causes a change in configuration of the flexible electrode array, and further the flexible electrode array and the fluidic component being arranged such that a change in configuration of the fluidic component causes the flexible electrode array to transition between a compressed configuration and an expanded configuration having a larger projected surface area than the compressed configuration.

[0017] In certain embodiments, in the compressed configuration, the flexible electrode array and optionally the fluidic components are rolled. Rolling the flexible electrode array takes advantage of the cross-section available in an incision, opening, lumen, or catheter of limited diameter. Rolling is also facilitated by devices with small bend radii at the points where the configuration is changed.

[0018] In certain embodiments, the transition between the compressed and expanded configurations involves unwinding the flexible electrode array, which may be about an axis parallel to the longitudinal extent of the device and / or about an axis perpendicular to a direction in which the electrode array and / or fluidic components have a small bending radius (e.g., the first direction in the above embodiment).

[0019] In the compressed configuration, the flexible electrode array and / or fluidic components may be substantially cylindrical and / or have a circular cross-section. Compressing the electrode array and / or fluidic components to a cylindrical shape or to have a circular cross-section optimizes packing of the device into the diameter available for insertion into a patient.

[0020] In the expanded configuration, the flexible electrode array may be substantially planar. Preferably, in the expanded configuration, the electrode array conforms to the organ or tissue with which it is intended to interact, either actively or passively. While such a structure may have some curvature, the overall configuration of the device may still be substantially planar, for example, compared to the compressed configuration.

[0021] Preferably, in the expanded configuration, the medical device has a thickness of 5 mm or less, more preferably 3 mm or less, more preferably 2 mm or less, and in some embodiments, 1 mm or less. The thickness of the device can be important to ensure reduced or minimized interaction with surrounding tissue. While expansion of the electrode array in the expanded configuration to have a larger projected area than in the compressed configuration is desirable to extend over a larger treatment or detection area than the electrode array inserted into the patient, expansion in thickness is generally less desirable and should be reduced and avoided if possible.

[0022] In certain embodiments, the electrode array and / or fluidic components are positioned such that the electrode array retains its deployed shape even when the fluidic components are subsequently partially or fully retracted. This can help reduce the thickness of the device in the deployed configuration. In such embodiments, the thickness of the medical device in the expanded or deployed configuration can be 0.5 mm or less, preferably 0.2 mm or less, and more preferably 0.1 mm or less.

[0023] Preferably, the medical device is arranged to limit the expansion of the thickness of the device during the change in configuration.

[0024] In certain embodiments, the medical device further includes a constraining layer disposed substantially parallel to the fluidic component and including one or more portions of a stiff or inelastic or low-elasticity material arranged to prevent or limit expansion of the fluidic component through the thickness of the device during a change in configuration. References to "inelastic" in the following description will be understood to include materials having a low level of elasticity. While a lower level of elasticity is preferred for the expansion-limiting function, some elasticity may be desirable for other purposes.

[0025] The section of rigid material may comprise a plurality of strips arranged substantially parallel to one another, with the portions of the constraining layer between said strips being highly flexible.

[0026] Alternatively or additionally, the sections of rigid material may be arranged so as not to prevent configuration changes in directions other than the thickness direction.

[0027] In certain embodiments, limiting vertical expansion is achieved by incorporating a relatively inelastic material in one or more layers above and / or below the fluidic component. This relatively inelastic material may resist deformation and thus limit vertical expansion. Similarly, a flexible but inelastic material above and / or below the fluidic component may prevent the fluid chamber from stretching or expanding to a larger volume. Such a material system may take the form of, for example, a thin layer of Parylene-C or polyimide, with or without a layer of silicone.

[0028] Such inelastic materials may be specifically configured to take into account the overall flexibility requirements of the device for the deployment process. This can be achieved, for example, by providing regions of flexible material between strips of rigid material, the strips being oriented perpendicular to the direction of unrolling or unfurling of the device during deployment, so that the flexible material ensures that the entire device remains flexible enough to deploy, and the rigid strips prevent or reduce perpendicular expansion by increasing the force required to cause such expansion.

[0029] Alternatively or additionally, materials can be used to form layers within the device above and / or below the fluidic component that have anisotropic properties, whereby the material is flexible in the direction of rolling / unrolling but stiff in the perpendicular direction (e.g., longitudinally).

[0030] In certain embodiments, the fluidic component comprises a fluidic channel extending therethrough, and the fluidic component further comprises at least one tie joining opposing sides of the fluidic channel so as to prevent or limit expansion of the fluidic channel in the thickness direction of the device during a change in configuration.

[0031] The tie(s) can be fabricated as part of the channel itself, or can be formed by bonding or welding between the top and bottom layers of the fluid channel. The tie can be a spot bond, with multiple such bonds distributed along the channel, or it can be continuous along all or part of the channel.

[0032] Alternatively or additionally, the fluidic component can include multiple independently expandable chambers sized to prevent or limit expansion of the fluidic channel through the thickness of the device during configuration changes. If the cross-section of the individual chambers or sections of the fluidic component is sufficiently small, vertical expansion can be prevented or limited. Thus, the overall design of the fluidic component can provide fluidic channels with small cross-sections. Multiple such channels may be arranged parallel to one another and joined at either end.

[0033] Alternatively or additionally, the fluidic component further includes a pressure valve fluidly disposed between the first and second independently expandable chambers, the pressure preventing fluid from passing from the first chamber to the second chamber until a predetermined fluid pressure is reached in the first chamber. Vertical expansion of the device can be limited by the design of the chamber geometry and the pressure limit set by the valve.

[0034] A further aspect of the present invention provides a medical device comprising a flexible electrode array and a fluidic component, the fluidic component being fluidically actuatable to cause the fluidic component to change configuration, the fluidic component and the flexible electrode array being configured such that a change in configuration of the fluidic component causes a change in configuration of the flexible electrode array, the device having a proximal section and a distal section, the flexible electrode array and the fluidic component being disposed in the distal section, the device further comprising a fluid connector in fluid communication with the fluidic component and an electrical connector in electrical contact with the electrode array, the connector being provided in the proximal section of the device for connecting the fluidic component and the electrode array to an external device.

[0035] The distal section of the device may be more flexible in at least one direction than the proximal section.

[0036] Thus, the distal section of the device can include flexible and reconfigurable components such as fluidic components and electrode arrays, while less flexible (or non-flexible) components such as connectors can be located at the proximal end, which preferably do not change configuration during deployment of the device.

[0037] The terms distal section and proximal section are intended to refer to the relative arrangement of the components described in this aspect. In particular, in certain embodiments, it is not contemplated that the device itself will include wires or other connectors (e.g., tubing) that serve to connect the device to additional apparatus or devices (such as controllers and / or fluids and / or power sources) that are external to the patient or at the patient's skin level after insertion of the device. Thus, the proximal section of the device can include only the components necessary to make connections to such items.

[0038] In such an arrangement, the proximal section of the device may form a relatively small proportion of the overall device, for example 20% or less, preferably 15% or less, more preferably 10% or less, more preferably 5% or less of the total volume of the device in the deployed state (such that the distal section having the active components comprises 80%, 85%, 90% or 95% of the volume of the device, respectively).

[0039] The device may further comprise a conductive connector connecting the electrode array to the electrical connector, and a first sheath surrounding the conductive connector, the first sheath being electrically insulating.

[0040] In certain embodiments, the device may further comprise a fluid channel connecting the fluidic component to the fluidic connector, the first sheath also surrounding the fluidic channel.

[0041] The device may further comprise a second, removable sheath surrounding the flexible electrode array, the fluidic components, and the first sheath. The second sheath can function to protect the fluidic components, the electrode array, and the connector(s) during insertion of the device into a patient and / or to prevent deformation of the device during insertion.

[0042] In particular, the flexible electrode array and fluidic components may be disposed in a compressed configuration within the second sheath, and the device is arranged such that actuation of the fluidic components after removal of the sheath causes the fluidic components and flexible electrode array to change to an expanded configuration having a larger projected surface area than the compressed configuration.

[0043] The inner diameter of the second sheath is preferably 1 cm or less, optionally 5 mm or less, and further optionally 2 mm or less.

[0044] According to another aspect of the present invention, there is provided a medical device comprising one or more of a flexible electrode array and a fluidic component, the fluidic component being fluidically actuatable to cause the fluidic component to change configuration, wherein the fluidic component and the flexible electrode array are configured such that a change in configuration of the fluidic component causes a change in configuration of the flexible electrode array.

[0045] Optionally, the medical device is a bioelectric implant. The bioelectric implant may be an active implant, such as a spinal cord stimulator. The bioelectric implant is a passive implant, such as an electrocorticography sensor.

[0046] Optionally, the flexible electrode array comprises electrodes disposed on a flexible substrate. The flexible substrate may be 500 μm or less in thickness, optionally 200 μm or less in thickness, further optionally 100 μm or less in thickness, further optionally 50 μm or less in thickness, further optionally 25 μm or less in thickness, further optionally 10 μm or less in thickness, and further optionally 5 μm or less in thickness. The flexible substrate may be made from a polymeric material, optionally a thermoplastic, and may optionally include one or more of polyurethane, silicone, parylene, polyimide, polyamide, cyclic olefin polymer, cyclic olefin copolymer, polyacrylate, polyethylene terephthalate, and / or epoxy.

[0047] Optionally, the flexible substrate comprises a fluidic component.

[0048] Optionally, the fluid component comprises a fluid inlet for supplying fluid into the fluid component.

[0049] Optionally, the fluidic component comprises a fluidic channel connected to the fluid inlet, the channel extending within the fluidic component.

[0050] Optionally, the fluid channel is not rigid.

[0051] Optionally, the fluid channel has a maximum undistended width dimension of 5 mm or less, optionally 3 mm or less, further optionally 1 mm or less, further optionally 500 μm or less, further optionally 100 μm or less, further optionally 50 μm or less, and / or has a maximum distended thickness of 5 mm or less, optionally 2 mm or less, further optionally 1 mm or less, further optionally 500 μm or less.

[0052] Optionally, the fluidic component is actuated by supplying a fluid to the fluidic channel.

[0053] Optionally, the fluid channel has a branched and / or symmetrical structure within the fluid component.

[0054] Optionally, the medical device may be configured in a first configuration having a diameter of 1 cm or less, optionally 5 mm or less, further optionally 2 mm or less, and further optionally 1 mm or less.

[0055] Optionally, the medical device is actuable by fluid actuation from said first configuration to an expanded configuration having a larger projected surface area than the first configuration.

[0056] Optionally, the device is configured such that fluid actuation unfurls or unfolds the fluid component, thereby unfurling or unfolding the flexible electrode array.

[0057] Optionally, the fluidic component is separate or separable from the flexible electrode array.

[0058] The fluidic components and flexible electrode array in any of the above devices may be separate or separable, allowing the fluidic components to be used to deliver and deploy the electrode array, but then withdrawn, leaving only the array in the patient. This can significantly reduce the size of the device retained within the patient and provide a lower level of disruption to surrounding tissues and organs (thus potentially reducing side effects from device implantation).

[0059] The medical device of any of the above embodiments may include one or more components that are imageable by X-ray, such as a strip of polymeric material infused with BaSO4, which allows for checking and / or monitoring the position of the device during and / or after it is deployed in a patient.

[0060] Unless otherwise indicated, any of the features (including optional or preferred features) described in connection with one of the above aspects is equally applicable in combination with a medical device according to any of the other above aspects.

[0061] According to a further aspect of the present invention, there is provided a method of using a medical device according to any of the foregoing aspects (including some, all or none of the optional and preferred features of these aspects), the method comprising at least one step of supplying fluid to the fluidic component to cause a change in configuration of the fluidic component, the fluidic component, when changing configuration, causing a change in configuration of the flexible electrode array.

[0062] Optionally, the method further comprises removing the fluid component from the flexible electrode array.

[0063] Optionally, the method further includes configuring the bioelectric implant in a first configuration suitable for deployment, deploying the bioelectric implant, and fluidically actuating the bioelectric implant to change the bioelectric implant from the first configuration to a second configuration.

[0064] The bioelectric implant may be deployed percutaneously or through a burr hole, optionally no greater than 20 mm in diameter, further optionally no greater than 10 mm, further optionally no greater than 5 mm, and further optionally no greater than 2 mm.

[0065] Optionally, the actuating step further comprises bringing an electrode of the bioelectric implant into contact with or proximity to the target tissue.

[0066] According to a further aspect of the present invention there is provided a method of treating the human or animal body, the method comprising the step of implanting a medical device or bioelectric implant according to any of the method variations of the above aspects.

[0067] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0068] [Figure 1] FIG. 1 is a diagram of a medical device comprising a flexible electrode array and a fluidic component. [Figure 2] 2A-2C show examples of (A) longitudinal and (B) lateral unfolding / expansion of a medical device such as that shown in FIG. 1. [Figure 3] 1A-1C illustrate various patterns that may be used for fluidic components of a medical device. [Figure 4] 1 illustrates a medical device according to one embodiment of the present invention. [Figure 5] 1A-1D illustrate a medical device and coatings for certain components of the device according to one embodiment of the present invention. [Figure 6]FIG. 10 illustrates deployment of the device into a spinal location. [Figure 7] 1A-1C are schematic diagrams illustrating cross-sectional configurations of fluid channels within a medical device. [Figure 8] FIG. 1 illustrates steps in the protocol for creating a flexible electrode array. [Figure 9] FIG. 10 shows steps of another protocol for making a flexible electrode array. [Figure 10] FIG. 10 illustrates steps in a protocol for combining fluidic components with a flexible electrode array. [Figure 11] FIG. 10 illustrates steps of another protocol for combining fluidic components with a flexible electrode array. [Figure 12] FIG. 10 illustrates steps of yet another protocol for combining fluidic components with a flexible electrode array. DETAILED DESCRIPTION OF THE INVENTION

[0069] The present disclosure relates to medical devices, particularly implantable bioelectronic devices, incorporating fluidic components that can be used to actuate the unfolding / unwinding of the device after implantation (note that "fluid" can be any of a liquid, gas, gel, or foam, or a combination thereof; "fluidic component" covers both pneumatic and hydraulic components, as well as components actuated by gels or foams, or a combination thereof; "fluidically actuable" means that a component may be actuated by any of a liquid, gas, gel, or foam, or a combination thereof). Providing a flexible device that can be rolled up before implantation allows the device to be deployed relatively easily, for example, percutaneously. Once deployed, the ability to control unfolding allows the device to be positioned as needed and have a relatively large active surface area compared to the size of the device in its rolled configuration.

[0070] Such a device addresses a significant shortcoming of other implant technologies, such as those used for spinal cord stimulation (SCS) mentioned above, in that it reduces the surgical invasiveness of implantation, allowing for percutaneous implantation of large implants.

[0071] In the following description, for ease of reference, the terms "gathered" or "compressed" configuration are used in contrast to "expanded" configuration. Those skilled in the art will understand that a gathered configuration can encompass any form or combination of folding, rolling, pleating, etc.

[0072] FIG. 1 illustrates a medical device 100. The medical device 100 may be, for example, a bioelectric implant. The bioelectric implant 100 may be an active implant, such as a spinal cord stimulation (SCS) device. Alternatively, the bioelectric implant may be a passive implant, such as an electrocorticography sensor. In other applications, the device 100 may have both active and passive functions. Other applications of such a device 100 include use in peripheral nerve implants or recording / stimulating muscle activity.

[0073] The medical device 100 includes a flexible electrode array 10. The flexible electrode array 10 includes electrodes 11 connected to conductive traces 12 disposed on a flexible substrate 30. As a non-limiting example, the flexible electrode array may be approximately 5 μm thick. The electrode array 10 is flexible so that it can change configuration in response to being actuated by a fluidic component 20, as described below. Accordingly, the phrase "flexible electrode array" is used herein to mean an array that can undergo such a change in configuration. This includes arrays that are fully flexible or semi-flexible (e.g., including some portions or features that are rigid or more rigid than other, more flexible portions, provided that they are still capable of undergoing a change in configuration actuated by a fluidic component).

[0074] The medical device 100 also includes a fluidic component 20. The fluidic component 20 is fluidically actuatable to cause the fluidic component 20 to change configuration, as described below. The fluidic component 20 can be a microfluidic component. In other arrangements, there may be one or more fluidic components, although a single fluidic component 20 is shown for ease of understanding.

[0075] The fluidic component 20 and the flexible electrode array 10 are configured such that a change in the configuration of the fluidic component 20 causes a change in the configuration of the flexible electrode array 10 .

[0076] In the illustrated embodiment, the substrate 30 of the electrode array 10 includes the fluidic component 20, so that a change in the configuration of the fluidic component 20 causes a change in the configuration of the electrode array 10. In this manner, the fluidic component 20 and the electrode array 10 are integrally connected.

[0077] However, in other configurations, the fluidic component 20 may be separate or separable from the electrode array 10. In fact, as will be understood from the description below, the fluidic component 20 and the electrode array 10 may not be connected by any means other than assembling the components together prior to implantation. An advantage of having separate or separable electrode array 10 and fluidic component 20 is that the fluidic component 20 can be removed after implantation of the electrode array 10. However, in other scenarios, it may be acceptable (or indeed preferable) to maintain the fluidic component 20 in situ and remain part of the implanted device 100.

[0078] Flexible substrate 30 may be 500 μm or less in thickness, optionally 200 μm or less in thickness, further optionally 100 μm or less in thickness, further optionally 50 μm or less in thickness, further optionally 25 μm or less in thickness, further optionally 10 μm or less in thickness, and further optionally 5 μm or less in thickness. A thin substrate facilitates the creation of small gathered configurations in medical device 100.

[0079] The flexible substrate 30 may be made from a polymeric material, optionally a thermoplastic, and may optionally include one or more of polyurethane, silicone, parylene, polyimide, polyamide, cyclic olefin polymer, cyclic olefin copolymer, polyacrylate, polyethylene terephthalate, and / or epoxy. Such materials are suitable for implantation within the body and provide flexibility that facilitates configuring the device into a gathered configuration that can be actuated into an expanded configuration.

[0080] 1, fluidic component 20 comprises a fluidic channel 21 extending through substrate 30 and having an inlet 22 and an outlet 23. Inlet 22 (and outlet 23) may be embodied, for example, as a tube formed separately and subsequently connected to fluidic channel 21.

[0081] The inlets 22 are for supplying fluid (i.e., liquid or gas) to the fluidic component 20. Generally, there may be one or more such inlets 22. Such supply actuates the fluidic component 20. Actuation can be the result of the supply increasing the fluid pressure and / or amount of fluid within the fluidic channels 21 of the fluidic component 20. In some arrangements, the supply of fluid can cause, for example, an expansion or straightening of the channels 21 in the substrate 30.

[0082] In some arrangements, there may not be a specific outlet 23 separate from the inlet 22. For example, when using a gas as the actuating fluid, the gas can be supplied to the inlet 22 to actuate the device 100, and then the supply can be removed, releasing the pressure within the channel 21 and allowing the gas to flow out of the channel 21 via the original inlet 22. In other arrangements, the channel 21 may extend from a dedicated inlet(s) 22 to one or more separate outlets 23.

[0083] In some arrangements, the fluidic component 20 may have independent fluidic channels 21, each with its own inlet 22 and outlet 23 (if present).

[0084] In either case, the path of the channels 21 through the substrate 30 can take different forms. The path form can be determined by how the device 100 is arranged in the gathered configuration and how it is desired for the device to transition to the expanded configuration. In some arrangements, the channels 21 may have a branched and / or symmetrical structure within the fluidic component 20. Such an arrangement can provide a uniform distribution of the channels 21 throughout the substrate 30, which can be advantageous for uniform deployment of the device 100. The channels 21 can take the form of a single chamber (e.g., having a "balloon" or "pillow" shape when inflated) or a series of interconnected chambers of that kind. Larger chambers may also have connecting ties or "pillars" from one side of the chamber to the other to help control the inflated shape and resist over-inflation.

[0085] 3 shows various patterns (in plan view) that may be used for the channels 21 of the fluidic components, although other patterns are possible. In the patterns, black represents the channels 21, and white areas within the black areas indicate areas where the channels 21 do not extend, such as the ties or "pillars" mentioned above, or larger areas of the substrate surrounded by the channels 21.

[0086] As can be seen, the patterns in Figures 3A, 3C, 3D, 3G, and 3H each have a single inlet (at the bottom of the pattern) that can function as both an inlet and an outlet. Figure 3B has two eccentric lines at the bottom, both of which can be used simultaneously as inlets and subsequently as outlets, or can serve as dedicated inlet and outlet lines. Figure 3E has a line approaching the pattern from the bottom and a line leaving the top, providing a natural "flow-through" arrangement, for example, where the bottom line functions as an inlet and the top line functions as an outlet, or vice versa. Figure 3F has three lines approaching from the bottom; as with Figure 3B, all of these can be used together as inlets or outlets, as needed, or can be individually dedicated as inlet or outlet channels. For example, the central line can be an inlet and the outer lines can be outlets, or vice versa.

[0087] It will also be observed that the patterns of Figures 3A, 3B, 3C, 3F, 3G, and 3H are essentially symmetrical. As discussed above, this can even aid in unwinding / spreading. The designs of Figures 3D and 3E are largely symmetrical, except for the single inlet / outlet line in 3D and the placement of the inlet / outlet line from the top of the pattern back to Figure 3E.

[0088] Considering the patterns individually, Figure 3A shows a channel 21 forming a single chamber. The chamber is of the "balloon" or "pillow" type and does not include ties. The chamber has a typical paddle shape that may correspond, for example, to the shape of an SCS electrode array.

[0089] Figure 3B shows channels forming a large chamber, but compared to Figure 3A, the chamber in Figure 3B is square in shape, the kind that may be useful for cortical sensors (designed for the surface of the brain). The chamber in Figure 3B also includes ties or "pillars" that connect the top and bottom sides of the chamber. These ties are shown as white circles and ovals. The ties help control how the chamber expands, strengthening the chamber design.

[0090] Figure 3C shows a branched channel design with branches in both directions (left and right) from a central channel. The branches are thicker toward the top of the pattern (i.e., away from the inlet / outlet lines at the bottom of the pattern). This arrangement provides less resistance to flow in the thicker branches and can help encourage fluid to fill the entire pattern when introduced, rather than simply filling from the end closest to the inlet.

[0091] FIG. 3D shows a similar bifurcation design to FIG. 3C, but the inlet line is offset laterally so that the bifurcation extends in one direction from that line (ie, to the right as shown).

[0092] Figure 3E shows a branched design in which the various branches branch off from the inlet branch before coming back together again. This design effectively creates enclosed regions of the substrate bounded by channels. Although the channels do not pass through those regions, the presence of channels around those regions means that the extent of the region is still operational.

[0093] Figure 3F is a multi-branched design that creates a network of channels and enclosed regions. Figure 3G is a similar design (but wider) with a different inlet arrangement, as previously described.

[0094] Figure 3H shows a branched design in which the initial branches are not interconnected, but each then branches further to form a local network of channels at different locations within the substrate. Such an approach may be desirable, for example, to provide a concentration of channels (i.e., networked regions) in areas corresponding to electrode locations to ensure that those areas are particularly well spread out.

[0095] Although various arrangements are described with respect to FIG. 3, those skilled in the art will recognize that these are exemplary only and that other variations and designs are possible, including designs having multiple independent fluid chambers.

[0096] In some arrangements, the fluid channel 21 may be completely embedded within the substrate 30, such that the channel 21 is defined only by the absence of substrate material within the channel. In other arrangements, the channel may be formed of a different material than the surrounding substrate 30, or may be formed of the same material as the substrate 30, but not directly embedded within it. The fluid channel may therefore be relatively flexible or rigid compared to the substrate, depending on the method of construction. In either case, the fluid channel may have a maximum unexpanded width dimension (i.e., the largest size across a cross section through the channel 21 perpendicular to the centerline of the channel 21 before the channel is expanded by pressurization or filled with fluid) of 5 mm or less, optionally 3 mm or less, further optionally 1 mm or less, further optionally 500 μm or less, further optionally 100 μm or less, further optionally 50 μm or less, and further optionally 5 μm or less. The fluidic channels may also have a maximum expanded thickness (i.e., the largest expanded dimension of the channel after it has been pressurized / filled with fluid to actuate the fluidic components) of 5 mm or less, optionally 2 mm or less, further optionally 1 mm or less, and even further optionally 500 μm or less.

[0097] 2 illustrates how the flexibility of medical device 100 can be utilized to assist in its deployment. Because both the electrode array 10 and the fluidic component 20 are flexible, the entire device 100 can be gathered into a configuration that can enable percutaneous deployment. In particular, the flexibility of the electrode array, and preferably at least the gathered fluidic component, can allow the medical device to be rolled without affecting the functionality of the electrode array.

[0098] 2A shows a side view of device 100 rolled along the longitudinal extent of device 100, i.e., device 100 is rolled along its longest axis. Device 100 can be unrolled into a relatively flat configuration, as shown on the right.

[0099] 2B shows an alternative arrangement (this time in plan view). On the left, device 100 is rolled or folded across the width of the device (the shorter direction in the plane of the electrode array 10 when expanded to a flat configuration). Again, the device may subsequently be unwound or unfolded to provide a fully deployed device, as shown on the right.

[0100] In both cases, the gathered configuration of device 100 allows for the possibility of percutaneous implantation of device 100. By providing an appropriately thin flexible substrate 30, even device 100 with a relatively large expanded surface area can be rolled into a relatively narrow configuration that allows for percutaneous deployment with a suitable needle. Preferably, the gathered configuration is such that the maximum width of the device in that configuration (i.e., in cross-section in the direction of gathering) is 1 cm or less, optionally 5 mm or less, and even optionally 2 mm or less. It is advantageous to make the maximum width as small as possible, thereby allowing smaller diameter needles to be used for percutaneous deployment. Therefore, it may be advantageous to roll device 100 at its narrower width dimension as opposed to its longer length dimension to achieve a smaller gathered width (because less material will be gathered).

[0101] While Figure 2A shows an example with a single roll, it may be advantageous to roll, fold, or otherwise gather the device in two directions, for example, from two edges to a centerline, as shown in Figure 2B. Such an arrangement can allow for more uniform deployment, as explained below. That is, it can allow both sides to deploy simultaneously, thereby avoiding twisting in situ as the device 100 is deployed.

[0102] The gathering method will be determined by the particular device but can be performed, for example, manually, using a guide, or in other ways, or may be automated. Gathering can use a guide component (which may be integrated into device 100 or a separate component) to provide additional rigidity / structure to the gathered device 100 and aid in percutaneous delivery. Such a guide component can take the form of a wire or tube, or a bioresorbable shank, either within or around the gathered device 100. That is, the guide component can provide a relatively rigid "backbone" or support around which the device 100 can be gathered and then used to help guide the device from within the gathered configuration to its deployed position. Alternatively, or in combination, the guide component can be a sheath or tube into which the device is delivered as / after being gathered, such that the guide component is external to the gathered device. In the case of an internal guide component, that component may or may not be removed once the device 100 is deployed. In the case of an external tube or sheath, the guide component must be withdrawn or retracted sufficiently relative to the device to allow for change to the deployed configuration (however, in some cases, this may be possible without retraction at all, for example, when internal and external guide components are used in combination).

[0103] In use, device 100 may be assembled as described above and then initially deployed according to methods known in the art. For example, the SCS device may be deployed percutaneously. Alternatively, the brain sensor may be deployed through a burr hole in the skull. Such a burr hole may be 20 mm or less in diameter, optionally 10 mm or less, optionally 5 mm or less, and optionally 2 mm or less.

[0104] After initial deployment, fluid can be supplied to inlet 22 to fill and / or pressurize channel 21. Once channel 21 is filled / pressurized, it is biased toward its expanded configuration, thus beginning to unfold / unfold fluidic component 20. Thus, the transition of fluidic component 20 from the gathered configuration to the expanded configuration is actuated by supplying fluid to fluidic channel 21. This transition brings the device into contact with or into suitable proximity to the target tissue.

[0105] A change in the configuration of the fluidic component 20 causes a change in the configuration of the associated flexible electrode array 10. In the embodiment of FIG. 1, the electrode array 10 includes a substrate 30 on which the fluidic component 20 is contained. As noted above, in other arrangements, the fluidic component 20 and the electrode array 10 may be separate or separable components that are each independently flexible. In these arrangements, the separate / separable components are grouped together such that, for example, even if the electrode array 10 and the fluidic component 20 do not share the same substrate 30, actuation of the fluidic component still causes a change in the configuration of the electrode array 10.

[0106] Fluid actuation of device 100 causes device 100 to expand into a configuration having a larger projected surface area than the expanded configuration. The expanded shape and area of ​​the electrode array will vary depending on the application. For example, an electrode array for a brain sensor may be relatively square or circular, e.g., up to 100 mm x 100 mm (i.e., 0.01 m). 2The fluidic component 20 may have dimensions of 30 mm x 300 mm (total area of ​​30 mm x 300 mm) or larger. In contrast, an SCS device may have a similar total area, but be relatively long and thin, with dimensions of up to 30 mm x 300 mm or larger. In either case, smaller devices can be used for more targeted sensing / stimulation. Additionally, the fluidic component 20 can act as a support to aid in positioning the extended electrode array 10. The fluidic component 20 can be filled, for example, with a self-hardening gel or foam after deployment to provide continued rigidity and support.

[0107] Once device 100 is deployed and positioned, the fluid provided to channels 21 can be removed. However, this is not required. For example, the fluid may be saline or the like, which poses no clinical risk in the unlikely scenario that the fluid somehow leaks from device 100. Similarly, optionally, fluid component 20 itself can be removed after positioning electrodes 10, provided that fluid component 20 and electrode array 10 are separate or separable. For example, if fluid component 20 and electrode array 10 are completely separate, fluid component 20 can be actuated to cause a change in configuration, thereby unfolding both the fluid component and electrode array 10, which can then be freely removed by unfolding fluid component 20.

[0108] Following deployment and positioning of the implant 100, the implanted device 100 can be used in a desired capacity, whether as a sensor or a stimulator in the treatment of a patient. Such treatment can include therapy or diagnosis, or can be part of a surgical procedure.

[0109] Figure 4 shows a medical device 100 of one embodiment of the present invention in an expanded state. Components of device 100 visible in Figure 4 are labeled using the same numbers as in Figures 1 and 2. Generally, an electrode array 10 comprising a plurality of Ti / Au or Pt electrodes 11 is seen overlying a substrate 30 at the distal or working end 110 of the device.

[0110] At the proximal end of the device, the first section 120 provides one or more fluid connectors 102 for fluid connection to connect the fluid component 20 to an external inflation device. The fluid connectors 102 are medical grade polyethylene tubing (although other materials may be used as noted above) and have an outer diameter of less than about 1 mm.

[0111] The second, more proximal section 130 provides one or more electrical connectors 101 for electrical connection of the electrode array 10 to external electronics, such as a pulse generator for stimulation or a sensor for recording data from the electrodes. The electrical connectors 101 are three copper / polyimide flex cables, each having a thickness of approximately 0.07 mm.

[0112] In the arrangement of FIG. 4 , the distal end 110 is the portion of the device 100 that can change its configuration from a gathered or compressed configuration to a larger, deployed configuration when the fluidic components are actuated. This distal end 110 is generally flexible, while the first and second sections 120, 130 at the proximal end of the device can be less flexible or even rigid, thereby allowing for secure connection from an external source to the fluidic components 20 and electrode array 10. It will be appreciated that the fluidic connector 102 and electrical connector 101 likely will not be directly connected to an external source, but may be connectors to additional elements, such as tubes or wires (not shown), that extend away from the medical device 100 and may extend through a lumen to the outside of the patient when the device 100 is deployed within the patient. The first and second sections 120, 130 are also not inflatable and do not change shape or configuration when the fluidic components are actuated.

[0113] In particular, the distal end 110 of the device 100, and in particular the electrode array 10, has a bend radius of 2 mm or less in the x-direction, as shown on the axis in Figure 4. This means that the device can be easily rolled into a gathered configuration by rolling about a centerline of the device 100 that is parallel to the z-direction, as shown in and described above in connection with Figure 2B, and then deployed from that rolled configuration to the arrangement shown in Figure 4 upon actuation of the fluidic components.

[0114] In the device 100 shown in Figure 4, the device is significantly less flexible to bending about an axis parallel to the illustrated x-direction (perpendicular to the z-direction). Thus, the device 100 shown in Figure 4 is not suitable for deployment in the manner shown in and described above in connection with Figure 2A. This arrangement allows the device 100 to have a particular stiffer or less flexible component in the distal portion 110, provided that the device 100 is aligned along the longitudinal extent of the device 100.

[0115] For example, distal portion 110 of device 100 may have a support (not shown) that extends in the z-direction along the central longitudinal axis of the device. This support can provide device 100 with support and rigidity that may be needed, for example, to facilitate deployment and / or to ensure that the device retains a desired longitudinal configuration when deployed. Despite this rigid or less flexible support, distal portion 110 of device 100 can still be assembled into a compressed configuration by wrapping both sides to form two coils (when viewed along the z-direction) that meet at the central axis.

[0116] It will be appreciated that in alternative embodiments, device 100 may be more flexible in the z-direction shown in Figure 4 and less flexible (or stiff) in the x-direction, allowing for rolling and unfolding of the device as shown in and described above in connection with Figure 2A. In such a device, the stiff or less flexible components of distal portion 110 may be aligned parallel to the x-direction (i.e., transverse to the longitudinal extent of device 100).

[0117] In such variations of device 100, the stiff or less flexible components of distal end 110 may be detachable or removable. For example, a stiff support may be used that extends along the longitudinal extent of device 100 during deployment into the patient to prevent the distal end of the device from collapsing or deforming during deployment. This support may then be removed once the device is in the desired position. In these variations of the device, once all of the stiff or less flexible components have been removed from the distal end, the distal end may be flexible in both the x- and z-directions and may have a similar bend radius in both directions.

[0118] In alternative embodiments, the distal end 110 of the device 100 may have no stiff or less flexible components and thus be similarly flexible in both the x and z directions. Such a device may be configured to allow deployment in both the x and z directions by unwinding or unfolding after the device has been deployed.

[0119] Figure 5 shows how device 100 as shown in Figure 4 and described above may be packaged for deployment. The device shown in Figure 5 is identical to the device shown in Figure 4, and the individual components will not be described again.

[0120] 5A shows how a first sheath or connecting tube 200 covers the fluid and electrical connectors. The first sheath 200 is medical-grade polyurethane with an inner diameter of approximately 1.5 mm and a wall thickness of approximately 0.07 mm (although, as noted above, alternative materials may be used). The first sheath 200 covers and protects the fluid and electrical connectors (and any additional tubing and / or wires to which they are connected).

[0121] 5B shows the device 100 in a rolled configuration (double rolled about an axis parallel to the z-direction as described in connection with FIG. 4 above) with the first sheath 200, both contained within a second sheath or deployment tube 300. The second sheath 300 is medical grade polyurethane with an inner diameter of approximately 1.82 mm and a wall thickness of approximately 0.15 mm (alternative materials may be used, as noted above).

[0122] It will be appreciated that in order to fit into the second sheath 300 in a double-wrapped configuration without damage, the distal portion 110 of the device, and therefore the fluidic component 20 and electrode array 10, must have a bending radius of less than 0.455 mm (1.82 mm / 2 = maximum available diameter space on each roll of 0.91 mm => 0.91 mm / 2 = maximum radius on each roll of 0.455 mm).

[0123] Figure 6 shows the deployment of a medical device 100, as shown in Figures 4 and 5, into a patient's spinal region 400, in accordance with an embodiment of the present invention. The device 100 shown in Figure 6 is an SCS device designed to be lateral to the spinal cord 410. In each of Figures 6A and 6B, the left-hand view is a lateral view of the patient along a cross section through the spinal cord, and the right-hand view is a transverse cross section through the spinal cord at the point where the device is located.

[0124] 6A shows how device 100 is inserted (e.g., using sheath 300 or other catheter delivery system) between vertebrae 420 and substantially parallel to spinal cord 410. The right-hand image shows how device 100 begins to deploy by fluid actuation that unwinds the two rolls outward, away from the centerline of device 100.

[0125] FIG. 6B shows the device 100 in a deployed state in which the device is fully unfolded or unfolded and has a substantially planar configuration, but flexibly conforms to the curvature of the spinal cord 410 such that the electrode array of the device is adjacent to the spinal cord.

[0126] 6A and 6B, it can be seen that the epidural space 430 available for deployment of device 100 is limited in the vertical direction in FIGS. 6A and 6B (the anterior-posterior (AP) dimension with respect to the patient). In order to deploy device 100 in this space, it is advantageous for the device to be able to unravel or unfold when it is in the gathered or compressed configuration in which it is initially inserted, so that its thickness in the vertical direction does not significantly (if at all) exceed the thickness of the device in that direction. Devices composed of multiple layers that unfold upon deployment are less well suited (if at all) for deployment in such spaces.

[0127] This limited space is particularly the case in the deployment of spinal cord stimulators and other devices in the spinal cord region 400, but similar limitations apply to the deployment of other medical devices, for example, in the brain region.

[0128] Not only does this mean that the space for deployment of device 100 is limited, but the limitation in this direction also means that any expansion of the device in this direction (i.e., perpendicular to the unwinding direction) must be limited, ideally not to substantially exceed (if at all) the thickness of the device in the gathered configuration in which it is inserted. Excessive expansion in the perpendicular direction can lead to damage to surrounding tissue, vascular occlusion, or other complications.

[0129] Simple expansion of a fluid component, as found in known inflatable devices, typically results in a thin, flat, deflated structure, e.g., 20-500 microns thick, that tends to expand and assume a bulbous shape, often with a circular or oval cross section up to 1 cm thick, which is not practical for the implementation described above in connection with FIG.

[0130] It has been suggested that the expanded thickness of a device can be controlled by limiting the amount or pressure of inflation fluid injected into the device during deployment. However, in practice, a significant pressure increase within the fluid components of the device is required to initiate deployment from the compressed configuration to the deployed configuration. Because the force required to cause expansion of the fluid components (and therefore the entire device) in the vertical direction is typically less than the force required to deploy the device, the expansion required for deployment in such devices inevitably results in undesirable vertical expansion.

[0131] Device 100 of certain embodiments of the present invention is designed to limit expansion of the device in the vertical direction (i.e., perpendicular to the direction of deployment of the device and / or perpendicular to the substantially planar arrangement of the device in its deployed configuration). In certain configurations, the device is limited such that the thickness of the device in the vertical direction in the deployed configuration (and preferably at all stages during deployment) is never greater than the dimension of the device in the same direction in the gathered configuration before deployment. In certain applications, this may be no more than a few millimeters (e.g., 2 mm, 3 mm, or 5 mm).

[0132] To achieve this, various arrangements of the device 100 and / or fluidic components 20 can be used. Of course, certain embodiments can combine two or more of the arrangements described further below.

[0133] In certain embodiments, limiting vertical expansion is achieved by incorporating a rigid (or alternatively inelastic or minimally elastic) material in one or more layers above and / or below the fluid channel 21. This rigid material resists deformation, thus limiting vertical expansion. The incorporation of such a rigid material must also take into account the overall flexibility requirements of the device for the deployment process. This can be achieved, for example, by providing regions of flexible material between strips of rigid material, the strips oriented perpendicular to the direction of unrolling or unfurling of the device during deployment, such that the flexible material ensures that the entire device remains flexible enough to deploy, while the rigid strips prevent or reduce vertical expansion by increasing the force required to cause such expansion.

[0134] In a variation of the above, the material can be used to form layers within the device above and / or below the fluid channel 21 that have anisotropic properties, whereby the material is flexible in the direction of rolling / unrolling but rigid or inelastic in the perpendicular direction (e.g., longitudinally).

[0135] In certain embodiments, the fluid channel 21 itself is configured to limit vertical expansion. For example, the fluid channel 21 may have a cross-section as shown in FIG. 7. FIG. 7A shows a schematic cross-section of the fluid channel 21 when the device 100 is in an unexpanded (i.e., compressed / collected) state (for convenience, the channel is shown flat, but in reality it would likely be rolled / bent in that state). The channel 21 is divided into multiple parallel sub-channels 21a by multiple ties or posts 21b that physically connect the top layer 21c and the bottom layer 21d, thereby limiting the vertical expansion of the fluid channel. The ties or posts 21b can be fabricated as part of the channel itself, or can be formed by bonding or welding between the top layer 21c and the bottom layer 21d. The ties or posts 21b can be spot junctions, with multiple such junctions distributed along the channel, or they can be continuous along all or part of the channel 21.

[0136] As shown in Figure 7B, as the device expands, the expansion of the fluidic channels 21 in the vertical direction is constrained or limited by the ties or posts 21b, thus allowing individual subchannels 21a to expand vertically, but controlling and limiting the overall expansion of the device.

[0137] Similarly, if the cross section of the fluid channel 21 is sufficiently small, vertical expansion can be prevented or limited for the individual sub-channels 21a shown in Figure 7. Thus, an overall design of the fluid channel 21 with a small cross section can be provided. Multiple such channels may be arranged parallel to one another and joined at either end.

[0138] In other embodiments, there are multiple fluid chambers defined along the fluid channel 21, arranged to fill sequentially as the device expands. Pressure control valves are positioned between each of the chambers so that the chamber expands to a predetermined pressure limit before the valve connecting to the next chamber is forced open. This process can be repeated throughout the device. Vertical expansion of the device can be limited by the design of the chamber geometry and the pressure limits set by the valves.

[0139] Having described the construction and use of device 100, the following sections explore options for fabricating such a device 100. The description presents two options for how the electrode array 10 can be formed, followed by three separate options for how the array can be integrated with the fluidic component 20. While these protocols refer to specific fabrication techniques, those skilled in the art will understand that other techniques may be alternatively used to fabricate the device, depending on the desired materials, etc. Such processes include, for example, photolithography processes, cast elastomer processes, and digital fabrication processes (controlled extrusion, additive manufacturing).

[0140] Electrode array fabrication As shown in step 1 of Figure 8, a clean, rigid substrate 41 (of any suitable material, such as glass or a silicon wafer) can be used for the deposition of a thin layer of flexible material 42 (which will ultimately form part of the electrode array 10). Suitable flexible materials include, but are not limited to, parylene, silicone, polyurethane, other thermoplastic polymers, and the like. Prior to the deposition of the flexible material 42, a release layer can be used to minimize adhesion between the flexible material film 42 and the rigid support 41 and facilitate release of the final structure.

[0141] The thin layer of flexible material 42 can then serve as a base on which electrodes and conductive lines are patterned (Figure 8, Steps 2-5). Patterning can use metals such as, but not limited to, gold, iridium, and / or platinum. Patterning can be achieved by lift-off techniques well known to those skilled in the art. Briefly, a photoresist layer 43 can be spin-coated (Figure 8, Step 2), soft-baked, and exposed (typically with UV light) using a contact aligner. The exposed photoresist 43 can then be developed in an appropriate developer (Figure 8, Step 3). A layer of adhesion promoter metal (typically chromium or titanium) can then be deposited. The thickness of that layer can be, for example, 5 nm to 10 nm. This can then be followed by the deposition of a relatively thick layer 44 of electrode / conductive material, such as gold or platinum (Figure 8, Step 4). That layer 44 can be, for example, 100 nm or thicker. Multilayer deposition of different metals can also be performed. The final metal pattern is obtained by lifting off the photoresist 43 in a suitable photoresist removal medium (aqueous solution or solvent / solvent mixture) (Figure 8, step 5).

[0142] Although not shown, the patterning of the electrodes and conductive lines can alternatively be performed by wet or dry etching of the metal layer. Another possible metal patterning technique is laser ablation of a conformal metal foil adhered to a thin plastic layer of the base.

[0143] Following creation of the patterned electrode array, microfabrication of device 100 can continue with the deposition of a second film of flexible material 42 (FIG. 8, step 6). This layer serves as a passivation layer for electrodes 11.

[0144] Optionally, an adhesion promoter can be used to improve adhesion between the base layer of flexible material 42 and the passivation layer. By way of example, a typical adhesion promoter for Parylene is A-174 (methacryloxypropyltrimethoxysilane). Alternatively, roughening the surface of the base plastic layer can also improve the adhesion of the passivation layer.

[0145] Another photoresist 43 can then be spin-coated, exposed, and developed using a suitable developer (FIG. 8, step 7), followed by, for example, reactive ion etching to define the device features (FIG. 8, step 8). Any remaining photoresist after the dry etching step can be removed using a suitable solvent. Alternatively, the device features can be defined, for example, by laser ablation of two thin plastic layers.

[0146] A third sacrificial layer of flexible material 42 can then be deposited onto this structure (Figure 8, step 9). To minimize adhesion, an anti-adhesion layer 45, for example a 2% v / v soap solution, can be spin-coated between the second and third layers of flexible material.

[0147] Fabrication can then continue with the deposition of a layer of photoresist 44 to define the electrode areas (FIG. 8, step 10). The photoresist 44 can then be exposed and developed, followed by dry etching of the sacrificial and passivation layers of flexible material 42 (FIG. 8, step 11). This step is then followed by lift-off of the remaining photoresist 43 in an appropriate photoresist removal medium (aqueous solution or solvent / solvent mixture) (FIG. 8, step 12).

[0148] After dry etching, an aqueous dispersion of conductive polymer 46 can be spin-coated onto the substrate (Figure 8, step 13). The conductive polymer 46 can be, for example, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) or can contain additives (e.g., 5% by volume ethylene glycol, 0.1% by volume dodecylbenzenesulfonic acid, 1% by weight (3-glycidyloxypropyl)trimethoxysilane (GOPS)). Multiple depositions can be used to control the thickness of the conductive polymer. A soft bake step (e.g., at 110°C for the PEDOT:PSS system described above) for, for example, 1 minute can be used between each deposition.

[0149] Finally (FIG. 8, step 14), the third sacrificial layer of flexible material 42 is removed to complete the patterning and hard bake of the conductive polymer (eg, 140° C. for 1 hour).

[0150] The above protocol involves patterning using an organic material (i.e., a conductive polymer such as PEDOT:PSS). However, device 100 can be fabricated without organic layer 46. In that case, the workflow is slightly different, as shown in FIG. 9 and described in connection with FIG. 8 above. Following creation of the etched device outline, a layer of photoresist 43 can then be applied to define the electrode regions (FIG. 9, step 9), the electrode regions can be etched (FIG. 9, step 10), and the remaining photoresist 43 can be removed.

[0151] Alternatively, other methods of patterning with organic materials such as PEDOT:PSS can be used, such as (1) dry etching, (2) dip coating, (3) photopolymerization, or (4) electropolymerization on the electrode surface.

[0152] Integration of electrode arrays with microfluidics A first strategy for integrating electrode arrays created by the methods described in connection with Figures 8 and 9 is shown in Figure 10, steps 15' to 21'. The device can be coated with a water-soluble sacrificial layer 51 (Figure 10, step 15'). This can be, for example, a PVA (polyvinyl alcohol) aqueous solution. The device can then be released from the rigid substrate 41 and repositioned on the same or a different rigid substrate 41 with the sacrificial layer 51 facing downwards (Figure 10, step 16'). A removable patterning material 52, such as glycerol, can be used to define the microfluidic structure (Figure 10, step 17') before depositing another layer of flexible material to seal the microfluidics (Figure 10, step 18'). The microfluidic outline is then defined (Figure 10, step 19'). The removable patterning material is then removed (Figure 10, step 20'), and tubes are placed and secured at the microfluidic inlets. The final structure is then released (Figure 10, step 21').

[0153] A second strategy for integrating electrode arrays created by the methods described in connection with Figures 8 and 9 is shown in steps 15" through 18" of Figure 11. The microfluidic structure is designed using CAD software. A thin, flexible, double-sided tape 53 is laser cut (e.g., CO2 laser cutting) to define the microfluidic structure (Figure 11, step 15"). One side of the tape can be permanently bonded to a pristine layer of flexible material 42 (which can be held on a support 41). Next, to seal the microfluidic structure, a bioelectrical device (e.g., created according to the methods described in connection with Figures 8 and 9) can be released from its substrate 41 (Figure 11, step 16") and then aligned and bonded to the other side of the tape (Figure 11, step 17"). Tubes can then be placed and secured to the microfluidic inlets. The final structure can then be released (Figure 11, step 18").

[0154] A third strategy for integrating electrode arrays created by the methods described in connection with Figures 8 and 9 is shown in Figure 12, steps 15''' through 19'''. Similar to the second strategy, a microfluidic structure can be designed using CAD software, and a thin, flexible, double-sided tape 53 can be laser cut (e.g., CO2 laser cut) to define the microfluidic structure (Figure 12, step 15'''). One side of the tape can be permanently bonded to an initial layer of flexible material 42 (which can be held on a support 41). The microfluidic device can then be realized by positioning an additional layer of flexible material 42 on the other side of the laser-cut double-sided tape 53 (Figure 12, step 16'''). An additional layer of double-sided tape can be placed on top of the microfluidic (Figure 12, step 17'''), followed by alignment and bonding of the bioelectrical device (Figure 12, step 18'''). Tubing can be placed and secured to the microfluidic inlets. The final structure can then be released (Figure 12, step 20''').

[0155] As a variation of the second and third strategies, instead of using double-sided tape, a different bonding strategy can be used, such as printing / stamping a viscous adhesive, or laser welding plastic.

[0156] The foregoing description is merely exemplary in nature and those skilled in the art will appreciate that modifications and variations to the disclosed embodiments are possible within the scope of the claims, which define the invention.

[0157] confirmation: This research has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 732032.

Claims

1. a flexible electrode array having a bending radius of 2 mm or less; a fluid component, the fluid component being fluidly actuatable to cause a deformation of the shape of the fluid component; A medical device comprising: the fluidic component and the flexible electrode array are configured such that the deformation of the shape of the fluidic component causes a deformation of the shape of the flexible electrode array; The medical device further comprises a removable support element, the support element providing rigidity to the medical device in one or more directions. Medical devices.

2. 2. The medical device of claim 1, wherein the medical device has a proximal section and a distal section, the flexible electrode array and the fluidic component are arranged in the distal section, and the distal section has a bend radius of 2 mm or less in a first direction.

3. The medical device of claim 2 , wherein the distal section has a bend radius in a second direction orthogonal to the first direction that is greater than the bend radius in the first direction.

4. The medical device of claim 3 , wherein the medical device is elongate and the first direction is perpendicular to a longitudinal axis of the medical device.

5. The medical device of claim 3 or 4, wherein when the removable support element is removed, the distal section has a bend radius of 2 mm or less in each of the first direction and the second direction.

6. 6. The medical device of claim 1, wherein the flexible electrode array and the fluidic component are arranged such that the deformation of the shape of the fluidic component causes the flexible electrode array to transition between a compressed configuration and an expanded configuration having a larger projected surface area than the compressed configuration.

7. The medical device of claim 6 , wherein in the compressed configuration, the flexible electrode array is rolled.

8. The medical device of claim 6 or 7, wherein in the compressed configuration, the fluidic component is coiled.

9. 9. The medical device of claim 6, wherein in the compressed configuration, the flexible electrode array is cylindrical.

10. The medical device of claim 6 , wherein the transition between the compressed configuration and the expanded configuration comprises unwinding the flexible electrode array.

11. 11. The medical device of claim 10 when dependent on claim 2, wherein the unwinding occurs about an axis perpendicular to the first direction.

12. The medical device of claim 6 , wherein in the expanded configuration, the flexible electrode array is planar.

13. 13. The medical device of claim 6, wherein in the expanded configuration, the medical device has a thickness of 5 mm or less.

14. The medical device of claim 13 , wherein in the expanded configuration, the medical device has a thickness of 2 mm or less.

15. 15. The medical device of any one of claims 6 to 14, wherein the medical device is arranged to limit expansion of the thickness of the medical device during shape deformation to no more than a certain amount.

16. The medical device of claim 13, further comprising a constraining layer including one or more portions of inelastic material arranged parallel to the fluid component and arranged to prevent or limit expansion of the fluid component in the thickness direction of the medical device to less than a certain amount during shape deformation.

17. 16. The medical device of claim 15, wherein the medical device further comprises a constraining layer comprising a plurality of strips of rigid material arranged parallel to the fluid component and parallel to each other, the portions of the constraining layer between the strips being more flexible than the strips.

18. 18. The medical device of claim 17, wherein the strips of rigid material are arranged so as not to impede deformation of the shape in directions other than the thickness direction.

19. 19. The medical device of any one of claims 15 to 18, wherein the fluid component comprises a fluid channel extending within the fluid component, and the fluid component further comprises at least one tie joining opposing sides of the fluid channel so as to prevent or limit expansion of the fluid channel in the thickness direction of the medical device to less than a certain amount during shape deformation.

20. 20. The medical device of any one of claims 15 to 19, wherein the fluid component comprises a plurality of independently expandable chambers, the chambers being sized to prevent or limit expansion of the fluid component in the thickness direction of the medical device to a certain amount during shape deformation.

21. 21. The medical device of claim 20, wherein the fluid component further includes a pressure valve fluidly arranged between a first chamber of the plurality of independently inflatable chambers and a second chamber of the plurality of independently inflatable chambers, the pressure valve configured to prevent fluid from passing from the first chamber to the second chamber until a predetermined fluid pressure is reached within the first chamber.

22. further comprising a fluid connector in fluid communication with the fluidic component and an electrical connector in electrical contact with the flexible electrode array, the fluid connector and the electrical connector being provided in the proximal section of the medical device for connecting the fluidic component and the flexible electrode array to an external device. A medical device according to claim 2 or any one of claims 3 to 18 dependent on claim 2.

23. 23. The medical device of claim 22, wherein the distal section of the medical device is more flexible than the proximal section.

24. 24. The medical device of claim 22 or 23, wherein the distal section comprises at least 90% of the volume of the medical device.

25. 25. The medical device of any one of claims 22 to 24, further comprising a conductive connector connecting the flexible electrode array to the electrical connector, and a first sheath surrounding the conductive connector.

26. 26. The medical device of claim 25, further comprising a fluid channel connecting the fluid component to the fluid connector, the first sheath also surrounding the fluid channel.

27. 27. The medical device of claim 25 or 26, further comprising a second removable sheath surrounding the flexible electrode array, the fluidic component, and the first sheath.

28. 28. The medical device of claim 27, wherein the flexible electrode array and the fluidic component are arranged in a compressed configuration within the second removable sheath, and the medical device is arranged such that actuation of the fluidic component after removal of the second removable sheath causes the fluidic component and the flexible electrode array to change to an expanded configuration having a larger projected surface area than the compressed configuration.

29. 29. The medical device of claim 27 or 28, wherein the inner diameter of the second removable sheath is 1 cm or less.

30. 30. The medical device of claim 29, wherein the inner diameter of the second removable sheath is 2 mm or less.

31. 31. The medical device of any one of claims 1 to 30, wherein the fluidic component and the flexible electrode array are separate or separable.

32. 32. The medical device of any one of claims 1 to 31, wherein the medical device includes one or more components that are imageable by X-ray.

33. 33. The medical device of any one of claims 1 to 32, wherein the flexible electrode array comprises electrodes disposed on a flexible substrate.

34. The fluidic component comprises a fluidic channel, the fluidic channel comprising: have a maximum uninflated width dimension of 5 mm or less, and / or having a maximum expanded thickness of 5 mm or less; 19. A medical device according to any one of claims 1 to 18.

35. 35. The medical device of claim 34, wherein the fluid channel has a maximum undistended width dimension of 500 μm or less.

36. 36. The medical device of claim 34 or 35, wherein the fluid channel has a maximum expanded thickness of 1 mm or less.

37. the fluid channel have a maximum uninflated width dimension of 5 mm or less, and / or having a maximum expanded thickness of 5 mm or less; A medical device according to claim 19 or any one of claims 20 to 25 dependent on claim 19.

38. the fluid channel have a maximum uninflated width dimension of 5 mm or less, and / or having a maximum expanded thickness of 5 mm or less; A medical device according to claim 26 or any one of claims 27 to 33 dependent on claim 26.

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