WO2025235283A1

WO2025235283A1 - Needle arrays with features for sensing degrees of attachment

Info

Publication number: WO2025235283A1
Application number: PCT/US2025/027217
Authority: WO
Inventors: Alexander LYNESS; Bingxi YAN
Original assignee: West Pharmaceutical Services Inc
Current assignee: West Pharmaceutical Services Inc
Priority date: 2024-05-09
Filing date: 2025-05-01
Publication date: 2025-11-13
Anticipated expiration: 2026-11-09

Abstract

Needle arrays and sensors with features for sensing degrees of attachment are disclosed. The needle arrays include a substrate and a first needle projecting from a surface of the substrate. The first needle includes a first feature spaced a first distance from the surface of the substrate. The first needle can sense an electrical property when the first feature is inserted into skin. The needle array includes a second needle projecting from the surface of the substrate. The second needle includes a second feature spaced a second distance from the surface of the substrate. The second needle can sense the electrical property when the second feature is inserted into the skin. The second distance is different from the first distance.

Description

NEEDLE ARRAYS WITH FEATURES FOR SENSING DEGREES OF ATTACHMENT

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/645,004, filed May 9, 2024, the entirety of which is incorporated herein for any and all purposes

TECHNICAL FIELD

[0002] This disclosure is generally directed to needle arrays, sensors, and processes, and more particularly to the needle arrays, sensors, and processes with features for sensing the degrees of attachment of the needle array to skin surface.

BACKGROUND

[0003] Some medicament delivery devices can be worn by a patient and can deliver medicament subcutaneously into the patient. Such devices can include needles to deliver the medicament. Some wearable delivery devices include needles that both deliver the medicament and that can sense physiological characteristics of the patient.

SUMMARY

[0004] There exists a need for wearable medicament delivery devices that can accurately sense different degrees of attachment of the wearable medicament delivery device to the surface of the skin of the patient. This need can be met by a needle array configured to sense an electrical property according to aspects of this invention. The needle array includes a substrate. The needle array also includes a first needle projecting from a surface of the substrate. The first needle may include a first feature spaced a first distance from the surface of the substrate. The first needle is configured to sense the electrical property when the first feature is inserted into skin. The needle array also includes a second needle projecting from the surface of the substrate. The second needle may include a second feature spaced a second distance from the surface of the substrate. The second needle is configured to sense the electrical property when the second feature is inserted into the skin. The second distance is different from the first distance.

[0005] Implementations may include one or more of the following features. The needle array where the second distance is less than the first distance. The first needle is longer than the second needle. The first feature is a tip of the first needle, and the second feature is a tip of the second needle. The first needle and the second needle each may include a tip, and the first needle and the second needle are each segmented into at least a first segment including the tip and a second segment that is proximal of the first segment. The second segment being more conductive than the first segment. The first feature is the first segment of the first needle, and the second feature is the second segment of the first needle. The first distance extends from the surface of the substrate to the tip of the first needle, and the second distance extends from the surface of the substrate to a distal edge of the second segment. The first segment of each of the first needle and the second needle is coated with a first coating, and the second segment of each of the first needle and the second needle is coated with a second coating having a conductivity greater than the first coating. The second distance is between 150 pm and 300 pm less than the first distance. The first distance is at least 600 pm, and the second distance is between 300 pm and 450 pm. The third distance is different from the first distance and the second distance. The third distance is at least 150 pm less than the second distance. The electrical property is at least one of impedance, resistance, or capacitance.

[0006] Another general aspect includes a sensor with a needle array configured to sense an electrical property. The needle array can include a substrate and a first needle projecting from a surface of the substrate. The first needle can include a first feature spaced a first distance from the surface of the substrate. The first needle is configured to sense the electrical property when the first feature is inserted into skin. The needle array can include a second needle projecting from the surface of the substrate. The second needle can include a second feature spaced a second distance from the surface of the substrate. The second distance is different from the first distance. The second needle is configured to sense the electrical property when the second feature is inserted into the skin. The sensor also includes a control system operatively connected to the needle array. The control system is configured to: receive data indicative of the electrical property from the first needle and the second needle, and determine, based on the data indicative of the electrical property⁷, a state of attachment of the needle array to a surface of the skin.

[0007] Implementations may include one or more of the following features. The sensor where the control system is configured to determine that the state of attachment of the needle array to the surface of the skin is a semi-attached state based on i) the data indicative of the electrical property of the first needle being outside of a threshold associated with the first feature, or ii) the data indicative of the electrical property⁷ of the second needle being outside of a threshold associated with the second feature. The control system is configured to determine that the state of attachment of the needle array to the surface of the skin is an attached state based on i) the data indicative of the electrical property of the first needle being outside of a threshold associated with the first feature, and ii) the data indicative of the electrical property of the second needle being outside of a threshold associated with the second feature. The control system is configured to determine that the state of attachment of the needle array to the surface of the skin is a detached state based on i) the data indicative of the electrical property of the first needle being above a threshold associated with the first feature, and ii) the data indicative of the electrical property of the second needle being above a threshold associated with the second feature. The second distance is less than the first distance. The first needle is longer than the second needle, the first feature is a tip of the first needle, and the second feature is a tip of the second needle. The first needle and the second needle each may include a tip, and the first needle and the second needle are each segmented into at least a first segment including the tip and a second segment that is proximal of the first segment. The second segment is more conductive than the first segment. The first feature is the first segment of the first needle, and the second feature is the second segment of the first needle. The first distance extends from the surface of the substrate to the tip of the first needle, and the second distance extends from the surface of the substrate to a distal edge of the second segment. The first segment of each of the first needle and the second needle is coated with a first coating, and the second segment of each of the first needle and the second needle is coated with a second coating having a conductivity greater than the first coating. The needle array is configured to transition from the first state of attachment to a second state of attachment during a period of time. The control system is configured to determine that the needle array is in the first state of attachment and assign, in response to the determination that the needle array is in the first state of attachment, a first time within the period of time. The control system is configured to determine that the needle array is in the second state of attachment and assign, in response to the determination that that the needle array is in the second state of attachment, a second time value within the period of time. The control system is configured to calculate the difference between the second time and the first time.

[0008] Various additional features and advantages of this invention will become apparent to those of ordinary skill in the art upon review of the following detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS [0009] The following detailed description is better understood when read in conjunction with the appended drawings. For the purposes of illustration, examples are shown in the drawings; however, the subject matter is not limited to the specific elements and instrumentalities disclosed. In the drawings:

[0010] FIG. 1 shows a schematic, bottom view of a sensor with a needle array;

[0011] FIG. 2 shows a schematic, cross section view of a first example of the needle array in a detached state;

[0012] FIG. 3 shows the schematic, cross section view of the first example of the needle array in an attached sate;

[0013] FIG. 4 shows the schematic, cross section view of the first example of the needle array in a first semi-attached state;

[0014] FIG. 5 shows the schematic, cross section view of the first example of the needle array in a second semi-attached state;

[0015] FIG. 6 shows a schematic, cross section view of a second example of the needle array in a detached state;

[0016] FIG. 7 shows the schematic, cross section view of the second example of the needle array in an attached sate;

[0017] FIG. 8 shows the schematic, cross section view of the second example of the needle array in a first semi-attached state;

[0018] FIG. 9 shows the schematic, cross section view of the second example of the needle array in a second semi-attached state;

[0019] FIG. 10 shows a process for determining a state of attachment of a needle array; and

[0020] FIG. 11 shows a process for calculating the rate of change in attachment states of a needle array.

DETAILED DESCRIPTION

[0021] Microneedles can be used in various applications to delivery medicament to a user or to measure parameters related to the medicament injection. Arrays containing multiple microneedles can be attached to a user, for example to the surface of the skin. During use, one or more of the microneedles can detach from the skin surface, resulting in improper delivery of medication and/or measurement of parameters. It may be advantageous to identify if. when, and/or how many microneedles are properly situated on the injection surface, as well as if, when, and/or how many of those microneedles detach. Identifying the rate of detachment of each microneedle can help determine when the microneedle array is no longer connected via the minimal number of microneedles so as to sufficiently deliver the medication and/or sufficiently measure injection parameters. Disclosed herein are embodiments of microneedles, microneedle arrays, and injection devices that can be used to qualify and quantify the state of attachment of one or more microneedles to the injection surface, as well as identify if, when, and/or how rapidly the microneedle is attaching or detaching to or from the surface and where portions of the microneedle are with respect to the injection surface.

[0022] FIG. 1 shows a schematic, bottom view of a sensor 1 with a needle array 100 according to some aspects of the invention. The needle array 100 can include a substrate 102. The substrate 102 can include a surface 104 that can extend along an x-axis and a y-axis of the substrate 102. The surface 104 can be configured to directly or indirectly contact the skin of a patient. The needle array 100 can include any number of needles that can sense an electrical property when inserted into the skin of a patient. The needles can be microneedles. The microneedles can be micron-scale needles and can include needles with one or more dimensions (e.g.. diameter, width, length, etc.) of less than about 1 mm (1000 pm). In embodiments, the needles can be greater than 1000 pm. For example, the needles can be between 1000 pm and 1500 pm, greater than 1500 pm, among other possibilities. The electrical property can be any electrical property that can be used to indicate that the needles are inserted into the skin. In embodiments, the electrical property can be impedance, resistance, capacitance, among other possibilities. The needles can be made of conductive materials (e.g., gold, titanium, platinum, other conductive metals, other conductive materials, combinations thereof, etc.) or non-conductive materials (e.g., silicon, polymer, among other possibilities) and be coated with conductive materials.

[0023] The needles can each include one or more features, such as a base, a tip opposite the base, and a body extending between the base and the tip. The needles can include various segments along the body and/or the tip and can include segmented coatings of different electrical conductivities, among other possibilities. Segmented coatings can be advantageous for their manufacturability. The needles can generate data indicative of the electrical property that is associated with the respective feature or features of the given needle. At least one of the features of at least one of the needles of the needle array 100 can be a different distance from the surface 104 than at least one other feature of at least one of the other needles. According to this configuration, the needle array 100 can sense the electrical property at at least two distances from the surface 104 of the substrate 102. Moreover, since in embodiments the surface 104 can directly attach to the skin of the patient, the needle array 100 can, based on the features of the given needle, sense the electrical property at at least two depths into the skin of the patient. The magnitudes of the at least two depths can be substantially the same or identical to the magnitudes of the at least two distances from the surface 104 of the substrate 102. The data indicative of the electrical property associated with the respective feature or features of the given needle can be used to determine different states of attachment of the needle array 100 to the skin of a patient. The different states of attachment can include, for example, an attached state, a detached state, and at least one semi-attached state. In embodiments, the needle array 100 can include more than two needles with features that are different distances from the surface 104 of the substrate 102 and/or that can be inserted into the skin of the patient at different depths. The data indicative of the electrical property associated with such features of the needles can be used to determine more than one different semi-attached state of the needle array 100. The states of attachment of the needle array 100 can be related to the position of one or more features of one or more needles relative to the skin of the patient and/or relative to one or more features of one or more other needles within the needle array 100.

[0024] In embodiments, the needle array 100 can include a first needle 106 projecting from the surface 104 of the substrate 102. The first needle 106 can include a first feature 108 spaced a first distance from the surface 104 of the substrate 102. The first needle 106 can sense the electrical property at least when the first feature 108 is inserted into the skin of the patient and the electrical property can be associated with the first feature being inserted a first depth into the skin. In embodiments, the first needle 106 can sense the electrical property when the first feature 108 is not within the skin of the patient and the magnitude of the electrical property can indicate that the first feature 108 is not within the skin of the patient. The first depth can be substantially the same as, or identical to, the first distance from the surface 104 of the substrate 102, such as when the surface 104 of the substrate 102 is directly attached to, or directly contacts, the skin of the patient. Alternatively, the first depth can be less than the first distance from the surface 104 of the substrate 102, such as when the needle array 100 is detached or semidetached from the skin of the patient and/or in embodiments in which the surface 104 does not directly contact the skin of the patient. The first feature 108 can be any of the previously described features including the tip of the first needle 106, different segments of the body and/or segmented coatings of different electrical conductivities on the body and/or the tip, and combinations thereof, among other possibilities. [0025] The needle array 100 can include a second needle 110 projecting from the surface 104 of the substrate 102. The second needle 110 can include a second feature 112 spaced a second distance from the surface 104 of the substrate 102. The second needle 110 can sense the electrical property at least when the second feature 112 is inserted into the skin of the patient and the electrical property can be associated with the second feature 112 inserted a second depth into the skin. The second depth can be substantially the same as or identical to the second distance from the surface 104 of the substrate 102, such as when the surface 104 of the substrate 102 is directly attached to, or in contact with, the skin of the patient. Alternatively, the second depth can be less than the second distance from the surface 104 of the substrate 102, such as when the needle array 100 is detached or semidetached from the skin of the patient and/or in embodiments in which the surface 104 does not directly contact the skin of the patient. In embodiments, the second needle 110 can sense the electrical property when the second feature 112 is not within the skin of the patient and the magnitude of the electrical property can indicate that the second feature 112 is not within the skin of the patient. The second feature 112 can be any of the previously described features including the tip of the second needle 110. different segments of the body and/or segmented coatings of different electrical conductivities on the body and/or the tip, and combinations thereof, among other possibilities. The second distance can be different from the first distance. For example, the second distance can be less than or greater than the first distance. The second depth can be different from the first depth. For example, the second depth can be less than or greater than the first depth. The needle array 100 can thus sense the electrical property at at least two different distances and from the surface 104 of the substrate 102 (i.e., the first distance and the second distance) and/or at at least two different depths within the skin (i.e., the first depth and the second depth). The data indicative of the electrical property from the features associated with the first distance (and/or the first depth) and the second distance (and/or the second depth) can be used to determine different states of attachment of the needle array 100 to the skin of a patient.

[0026] In embodiments, the needle array 100 can include a third needle 114 projecting from the surface 104 of the substrate 102. The third needle 114 can include a third feature 116 spaced a third distance from the surface 104 of the substrate 102. The third needle 114 can sense the electrical property at least when the third feature 116 is inserted into the skin of the patient and the electrical property' can be associated with the third feature 116 inserted a third depth into the skin. The third depth can be substantially the same as or identical to the third distance from the surface 104 of the substrate 102, such as when the surface 104 of the substrate 102 is directly attached to, or in contact with, the skin of the patient. Alternatively, the third depth can be less than the third distance from the surface 104 of the substrate 102, such as when the needle array 100 is detached or semi-detached from the skin of the patient and/or in embodiments in which the surface 104 does not directly contact the skin of the patient. In embodiments, the third needle 114 can sense the electrical property when the third feature 116 is not within the skin of the patient and the magnitude of the electrical property can indicate that the third feature 1 16 is not within the skin of the patient. The third feature 1 16 can be any of the previously described features including the tip of the third needle 114, different segments of the body and/or segmented coatings of different electrical conductivities on the body or the tip, and combinations thereof, among other possibilities. The third distance can be different from each of the first distance and the second distance. For example, the third distance can be less than or greater than the first distance and can be less than or greater than the second distance. The third depth can be different from each of the first depth and the second depth. For example, the third depth can be less than or greater than the first depth and can be less than or greater than the second depth. The needle array 100 can thus sense the electrical property at at least three different distances from the surface 104 of the substrate 102 (i.e., the first distance, the second distance, and the third distance) and/or and at least three different depths within the skin (i.e., the first depth, the second depth, and the third depth). The data indicative of the electrical property from the features associated with the first distance (and/or the first depth), the second distance (and/or the second depth), and the third distance (and/or the third depth) can be used to determine different states of attachment of the needle array 100 to the skin of a patient. The different states of attachment can include, for example, an attached state, a detached state, a first semiattached state, and a second semi-attached state, as described further below. The signals associated with the varying stages of attachment can be used to reduce instances of wet injections (i.e., incomplete injections that cause the medicament to leak onto an external skin surface) and/or report on other anomalies, such as adverse events, that may occur during an injection.

[0027] The needle array 100 can include any number of first needles 106. second needles 110, and third needles 114. For example, and as shown in FIG. 1, the needle array 100 can include an alternating pattern of first needles 106, second needles 110, and third needles 114 arranged along the x-axis and/or the y-axis of the substrate 102. In embodiments, the comers of the substrate 102 can each include a first needle 106. though other configurations are possible including one or more different types of needles at the comers. In embodiments, the needle array 100 can include any number of other types of needles including fourth needles, fifth needles, etc.

[0028] In embodiments, the needle array 100 can include pairs of first needles 106. One needle of each pair of first needles 106 can be wired to a positive terminal for the first needles 106 of the needle array 100 and the other needle of each pair of first needles 106 can be wired to a negative terminal of the needle array 100 and the electrical properly can be measured across the positive and negative terminals. In embodiments, the needle array 100 can include pairs of second needles 110. One needle of each pair of second needles 110 can be wired to a positive terminal for the second needles 110 of the needle array 100 and the other needle of each pair of second needles 110 can be wired to a negative terminal of the needle array 100 and the electrical property can be measured across the positive and negative terminals. In embodiments such as shown in FIG. 1, pairs of first needles 106 can overlap (e.g., along the x-axis) with pairs of second needles 110. In alternative embodiments not shown, the first needles 106 of the pairs of first needles 106 can be arranged adjacent to each other (e.g., along the x-axis) without other types of needles disposed between the pairs of first needles 106. In alternative embodiments not shown, the second needles 110 of the pairs of second needles 110 can be arranged adjacent to each other (e.g., along the x-axis) without other types of needles disposed betw een the pairs of second needles 110. The third needles 114 or other types of needles can be arranged together in manners similar to or the same as any of the described pairs of first needles 106 and/or pairs of second needles 110. Moreover, other wiring arrangements for any of the needles described herein are possible.

[0029] The needle array 100 can be operatively connected to a control system 120. The control system 120 can receive data from the needle array 100 and can use the data to determine the attachment state of the needle array 100, as described further below. In embodiments, the control system 120 can be independently operatively connected to each of the needles of the needle array 100 such that the control system 120 can receive unique data attributable to each individual needle of the array. This can be advantageous by providing the greatest amount of data resolution possible for each needle of the needle array 100. In alternative embodiments, some or all of the different types of needles (e.g.. the first needle 106, the second needle 110, and the third needle 114) can be connected to a common connection. In such embodiments, the control system 120 can receive, through the common connection, data from multiple needles of the same type. This can be advantages in that the architecture of the needle array 100 can be simplified. In embodiments, the needle array 100 and the control system 120 together can form a sensor 1. Alternatively, some or all of the aspects of the control system 120 can be performed remotely from the needle array 100. The control system 120 can include any combination of processors, memories, circuits, input/outputs, transmitters, receivers, transceivers, power supplies, etc. Moreover, any of the capabilities or processes implemented by the control system 120 can be coded onto non- transitory computer readable media and can be executed by a processor.

[0030] In embodiments, the sensor 1 can be used together with one or more injection needles in a medical device configured to deliver a medicament to a patient. Th medical device can be a wearable medical device that can be prefilled with a medicament or be configured to receive a medicament container therein. Data from the sensor 1 regarding the state of attachment of the needle array 100 can be used to control injection of the medicament from the medical device. For example, the control system 120 can use the data from the sensor 1 to determine whether the needle array is attached, semi-attached, or detached form the skin and can control injection of the medicament based on that determination. This can reduce injection errors. Such application is not limited to the sensor 1 or to the needle array 100 and can be used with any of the embodiments of sensors and/or needle arrays described throughout this disclosure.

[0031] FIGS. 2-5 show views of a first example of a needle array 200 according to some aspects of the invention. Except where clearly mutually exclusive, the needle array 200 can include any of the features, structures, relationships, etc. of the needle array 100, and vice versa. For example, the needle array 200 can include the substrate 202 with surface 204, the first needle 206 with the first feature 208, the second needle 210 with the second feature 212, and the third needle 214 with the third feature 216. The needle array 200 can be a part of the sensor 1 and used together with the control system 120. The needle arrays are shown within planes defined by an x-axis and a z-axis that can be orthogonal to the x-axis and orthogonal to the y-axis described with respect to FIG. 1.

[0032] The needle array 200 can include three first needles 206 spaced apart along the substrate 202. For example, the three first needles 206 can be spaced apart along the x- axis of the substrate 202. though other arrangements on the substrate 202 and other numbers of first needles 206 greater than or less than three as possible. A second needle 210 can be arranged between the two of the first needles 206. For example, the second needle 210 can be arranged along the x axis between two of the first needles 206, though other arrangements on the substrate 202 and other numbers of second needles 210 greater than one second needle 210 are possible. A third needle 214 can be arranged between the two of the first needles 206. For example, the third needle 214 can be arranged along the x-axis between a different combination of two first needles 206, though other arrangements on the substrate 202 and other numbers of third needles 214 greater than one third needle 214 are possible. In embodiments not show n, the needle array 200 can include only two different types of needles such as only first needles 206 and second needles 210, only first needles 206 and third needles 214, only second needles 210 and third needles 214, etc.

[0033] The heights/lengths of the different types of needles of the needle array 200 can be different. For example, the first feature 208 of the first needle 206 can be a tip of the first needle 206. The tip of the first needle 206 can project a first distance di, along the z-axis, from the surface 204 of the substrate 202. The first distance di can correspond to a height or length of the first needle 206. The second feature 212 of the second needle 210 can be a tip of the second needle 210. The tip of the second needle 210 can project a second distance d2, along the z-axis, from the surface 204 of the substrate 202. The second distance d2 can correspond to a height or length of the second needle 210. The second distance d2 can be less than the first distance di. The third feature 216 of the third needle 214 can be a tip of the third needle 214. The tip of the third needle 214 can project a third distance ds, along the z-axis. from the surface 204 of the substrate 202. The third distance ds can correspond to a height or length of the third needle 214. The third distance ds can be less than the first distance di and less than the second distance d2. In embodiments, the first distance di can be at least 600 pm, between 600 pm and 1500 pm, or greater than 1500 pm. The second distance d2 can be between 300 pm and 450 pm and/or between 150 pm and 300 pm less than the first distance di, and the third distance can be between 150 pm and 300 pm and/or between 150 pm and 300 pm less than the second distance d2, among other possibilities.

[0034] FIG. 2 shows a schematic, cross section view of the needle array 200 in a detached state. In the detached state, each of the tips (i.e., the first feature 208, the second feature 212, the third feature 216) of the first needle 206, the second needle 210, and the third needle 214 are spaced from the skin of the patient along the z-axis such that the needles are detached from, and are not inserted into, the skin of the patient. As a result, the first needles 206, the second needle 210, and the third needle 214 can be used to identify and/or measure a parameter that can be used to generate data indicative of the electncal property outside of a threshold (e g., above or below a threshold value or range of threshold values) that indicates that the respective tips are each detached from/not inserted into the skin. For example, in embodiments in which measurable parameter is an electrical property of impedance, each of the first needles 206. the second needle 210. and the third needle 214 can generate data indicative of the impedance outside of a threshold impedance (e.g., above or below a threshold impedance value or range of threshold impedance values) that indicates that the respective tips are each detached from/not inserted in the skin. It will be appreciated that the acceptable impedance ranges will depend on the materials selected, geometry of the needles, the density of the needles, among other factors. Generally, the impedance value measured when the tips are inserted in the skin will be lower than the impedance value when the needles are separated from the skin, such as shown in FIG. 2. The impedance value when the needle tips are detached from/not inserted in the skin can be multiple magnitudes higher than the impedance value generated when the needle is inserted in the skin, for example.

[0035] FIG. 3 shows the schematic, cross section view of the needle array 200 in an attached sate. In the attached state, each of the tips (i.e. , the first feature 208, the second feature 212, the third feature 216) of the first needles 206, the second needle 210, and the third needle 214 are inserted in the skin of the patient. As a result, the first needles 206, the second needle 210, and the third needle 214 can generate data indicative of the electrical property' outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that the respective tips are each inserted in the skin at respective first, second, and third depths, as previously described. In the attached state, the first depth that the first needles 206 are inserted into the skin can be substantially the same as or identical to the first distance di from the surface 204 of the substrate 202, the second depth that the second needle 210 is inserted into the skin can be substantially the same as or identical to the second distance d2 from the surface 204 of the substrate 202, and the third depth that the third needle 214 is inserted into the skin can be substantially the same as or identical to the third distance ds from the surface 204 of the substrate 202. For example, in embodiments in which the electrical property is impedance, each of the first needles 206, the second needle 210, and the third needle 214 can generate data indicative of the impedance outside of a threshold (e.g.. above or below a threshold impedance value or range of threshold impedance values) that indicates that the respective tips are inserted in the skin. As discussed previously, it will be appreciated that the acceptable impedance ranges will depend on the materials selected, geometry of the needles, the density of the needles, among other factors. Generally, the impedance value measured when the tips are inserted in the skin, as shown in FIG. 3, will be low er than the impedance value when the needles are separated from the skin, such as shown in FIG. 2. The impedance value when the needle tips are inserted in the skin can be multiple magnitudes lower than the impedance value generated when the needle is detached from/not inserted in the skin. [0036] FIG. 4 shows the schematic, cross section view of the needle array 200 in a first semi-attached state. In the first semi-attached state, each of the tips (i.e., the first feature 208, the second feature 212) of the first needles 206 and of the second needle 210 can be inserted in the skin of the patient while the tip (i.e., the third feature 216) of the third needle 214 can be detached from/not inserted in the skin. In the first semi-attached state, the first depth that the first needles 206 are inserted into the skin can be less than the first distance di from the surface 204 of the substrate 202 and the second depth that the second needle 210 is inserted into the skin can be less than the second distance d2 from the surface 204 of the substrate 202. As a result, the first needles 206 and the second needle 210 can generate data indicative of the electrical property' outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that the respective tips are each inserted in the skin while the third needle 214 can generate data indicative of the electrical property outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that the tip of the third needle 214 is detached from/not inserted in the skin.

[0037] FIG. 5 shows the schematic, cross section view of the needle array 200 in a second semi-attached state. In the second semi-attached state, each of the tips (i.e.. the first feature 208) of the first needles 206 can be inserted in the skin of the patient while each of the tips (i.e., the second feature 212 and the third feature 216) of the second needle 210 and of the third needle 214 can be detached from/not inserted in the skin. In the second semiattached state, the first depth that the first needles 206 are inserted into the skin can be less than the first distance di from the surface 204 of the substrate 202. As a result, the first needles 206 can generate data indicative of the electrical property' outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that the respective tips are each inserted in the skin while each of the second needle 210 and the third needle 214 can generate data indicative of the electrical property outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that the tips of the second needle 210 and the third needle 214 are detached from/not inserted in the skin.

[0038] The ability to identify varying degrees of attachment (i.e., the attached state, the detached state, the first semi-attached state, the second semi-attached state, among other possibilities) of the needle array 200 can be advantageous, for example, for determining whether or not to inject a given medicament from the needle array 200. For example, some medicaments may be best administered when the needle array 200 is fully attached to the skin, while others may only require a degree of semi-attachment such as the first semiattached state and/or the second semi-attached state. The ability⁷ to distinguish between varying degrees of atachment can improve the efficacy of medicament injection and/or usability of the needle array 200, among other advantages. In some aspects, delivery of a medicament can be varied based on the degree of atachment of the needle array 200. For example, medicament can be delivered through one or more of any of the first needles 206, the second needles 210, and/or the third needles 214 when the needle array 200 is in the attached state, but medicament can be precluded from being delivered when the needle array 200 is in the first semi-atached state, second semi-atached state, or detached state. In some aspects, the rate of delivery of medicament can be varied based on the atachment state of various needles within the needle array 200. For example, medicament can be delivered at a faster rate, or in a larger quantity , when relatively more of the needles are in the atached state than when relatively fewer of the needles are in the atached state. For example, medicament can be delivered at a faster rate or at a greater volume when the needle array 200 is in the atached state than when the needle array 200 is in the first semi-atached state; and medicament can be delivered at a faster rate or at a greater volume when the needle array 200 is in the first semi-atached state than when the needle array 200 is in the second semiattached state.

[0039] In some aspects, delivery of the medicament can be routed to different needles based on their respective atachment state. For example, when the first needles 206, the second needles 210, and the third needles 214 are in the attached state to the skin, medicament can be delivered through all three needles, but if any one of those needles becomes detached, the medicament can be precluded from being delivered to the detached needles while continuing to be delivered through the atached needles.

[0040] FIGS. 6-9 show views of a second example of the needle array 300 according to some aspects of the invention. Except where clearly mutually exclusive, the needle array 300 can include any of the features, structures, relationships, etc. of the needle arrays 100, 200 and vice versa. For example, the needle array 300 can include the substrate 302 with the surface 304 and needles 306. The needle array 300 can be a part of the sensor 1 and used together with the control system 120.

[0041] The needle array 300 can include five needles 306 spaced apart along the substrate 302. For example, the five needles 306 can be spaced apart along the x axis of the substrate 302, though other arrangements on the substrate 302 and other numbers of needles 306 greater than or less than five as possible. Each of the needles 306 can be the same type of needle (e.g., the first needle, the second needle, the third needle, etc.). For example, the heights/lengths of the needles of the needles 306 can each be the same. Alternatively, the needle array 300 can include different types of needles, as previously described.

[0042] In embodiments, each needle 306 can include the first feature 308, the second feature 312, and the third feature 316. In embodiments not shown, each needle 306 can include any number of different features including two different features, four different features, among other possibilities. For example, each needle 306 can be segmented into segments with different electrical properties (e.g.. conductivities). The different segments can be formed of and/or coated with materials having different electrical properties. In some aspects, the different segments can be formed of and/or coated with the same material along the needle 306 but having different dimensions (e g., thickness of coating or width of the needle itself). The first feature 308 can be a first segment of the needle 306 and can include a tip 330 of the needle 306. The second feature 312 can be a second segment of the needle 306 that is proximal to the first segment (i.e., the first feature 308) with electrical properties different from the first segment. For example, the second segment can have a conductivity that is greater than or less than the conductivity of the first segment. The third feature 316 can be a third segment proximal to the second segment (i.e.. the second feature 312) with electrical properties different from the first segment and different from the second segment. For example, the third segment can have a conductivity⁷ that is greater than or less than the conductivity of each of the first segment and the second segment.

[0043] The first feature 308 can be disposed at a first distance di. along the z-axis. from the surface 304 of the substrate 302 to the tip 330. The second feature 312 can be disposed at a second distance d2, along the z-axis, from the surface 304 of the substrate 302 to a distal edge 332 of the second feature 312 at an interface between the first feature 308 and the second feature 312. The second distance d2 can be less than the first distance di. The third feature 316 can be disposed at a third distance ds, along the z-axis, from the surface 304 of the substrate 302 to a distal edge 334 of the third feature 316. The third distance ds can be less than the first distance di and less than the second distance d2. In embodiments, the first distance di can be at least 600 pm. between 600 pm and 1500 pm, or greater than 1500 pm. The second distance ds can be between 300 pm and 450 pm and/or between 150 pm and 300 pm less than the first distance di, and the third distance can be between 150 pm and 300 pm and/or between 150 pm and 300 pm less than the second distance d2, among other possibilities.

[0044] FIG. 6 shows a schematic, cross section view of the needle array 300 in a detached state. In the detached state, each of the tips 330 of the needles 306 are detached from/not inserted in the skin of the patient. As a result, the needles 306 can generate data indicative of the electrical property (e.g., an impedance) outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that the respective tips 330 are each detached from/not inserted in the skin, as described previously.

[0045] FIG. 7 shows a schematic, cross section view of the needle array 300 in the attached sate. In the attached state, each of the tips 330, the first features 308, the second features 312. and the third features 316 of the needles 306 are inserted in the skin of the patient. As a result, the needles 306 can generate data indicative of the electrical property outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that each of the tips 330. the first features 308, the second features 312, and the third features 316 of the needles 306 are inserted in the skin of the patient. For example, in embodiments the third feature 316 can have a conductivity that is greater than a conductivity of each of the first feature 308 and the second feature 312. In the attached state, the electrical property⁷ (e g., impedance) can be an impedance associated with the conductivity of the third feature 316 within the skin. In the attached state, the depth that the needles 306 are inserted into the skin can be substantially the same as or identical to the first distance di from the surface 304 of the substrate 302 to the tips 330 of the needles 306.

[0046] FIG. 8 shows a schematic, cross section view of the needle array 300 in a first semi-attached state. In the first semi-attached state, each of the tips 330, the first features 308, and the second features 312 of the needles 306 are inserted in the skin of the patient, while the third features 316 of the needles 306 can be detached from/not inserted in the skin. As a result, the needles 306 can generate data indicative of the electrical property⁷ outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that each of the tips 330, the first features 308, and the second features 312 of the needles 306 are inserted in the skin of the patient but not the third features 316. For example, in embodiments the second feature 312 can have a conductivity that is greater than a conductivity⁷ of the first feature 308 and less than the conductivity⁷ of the third feature 316. In the first semi-attached state, the electrical property⁷ (e.g., impedance) can be an impedance greater than the impedance of the attached state but less than the impedance of the detached state. In the first semi-attached state, the first depth that the needles 306 are inserted into the skin can be less than the first distance di from the surface 304 of the substrate 302 to the tips 330 of the needles 306.

[0047] FIG. 9 shows a schematic, cross section view of the needle array 300 in a second semi-attached state. In the second semi-attached state, each of the tips 330 and at least part of the first features 308 are inserted in the skin of the patient, while the second features 312 and the third features 316 of the needles 306 can be detached from/not inserted in the skin. As a result, the needles 306 can generate data indicative of the electrical property outside of a threshold (e.g., above or below a threshold value or range of threshold values) that indicates that each of the tips 330 and the first features 308 of the needles 306 are inserted in the skin of the patient, but not the second features 312 or the third features 316. For example, in embodiments the first features 308 can have a conductivity that is less than the conductivity of each of the second features 312 the third features 316. In the second semiattached state, the electrical property (e.g., impedance) can be an impedance greater than the impedance of the attached state and greater than the impedance of the first semi-attached state, but less than the impedance of the detached state. In the second semi-attached state, the first depth that the needles 306 are inserted into the skin can be less than the first distance di from the surface 304 of the substrate 302 to the tips 330 of the needles 306. It will be appreciated that the needles of the needle array 300 can be arranged such that either all of the needles are in the same state (e.g., detached, attached, first semi-attached, or second semiattached) or where some of the needles are in one attachment state while other needles are in another attachment state.

[0048] As described previously, the ability to identify varying degrees of attachment (i.e., the attached state, the detached slate, the first semi-attached state, the second semiattached state, among other possibilities) of the needle array 300 can be advantageous, for example, for determining whether or not to inject a given medicament from the needle array 300. For example, some medicaments may be best administered when the needle array 300 is fully attached to the skin, while others may only require a degree of semi-attachment such as the first semi-attached state and/or the second semi-attached state. The ability’ to distinguish between varying degrees of attachment can improve the efficacy of medicament injection and/or usability of the needle array 300, among other advantages.

[0049] FIG. 10 shows an example process 1000 for determining a state of attachment of a needle array. The process 1000 can be used with and/or used to determine a state of attachment of the needle array 100, as described later. In embodiments, the process 1000 can be used with and/or used to determine a state of attachment of any of the needle arrays described herein including any embodiments of the needle arrays 100, 200, 300 described previously. The process 1000 can be implemented by the control system 120.

[0050] The process 1000 can begin, at step 1002, by receiving data indicative of an electrical property from the first needle 106 and the second needle 110. The data indicative of the electrical property' from the first needle 106 and the second needle 110 can be data indicative of the impedance from the first needle 106 and the second needle 110, though other electrical properties are possible, as previously described. Although the process 1000 is described with two needles, the process 1000 can function with data from any number of the needles of any of the previously described needle arrays.

[0051] The process 1000, at steps 1004, 1006, and 1008, can determine whether the data indicative of the electrical property from the first needle 106 and the second needle 110 is outside of a threshold (e g., above or below a threshold value or range of threshold values) for each of the first needle 106 and the second needle 110. In embodiments such as shown in FIG. 10, the threshold can be an attachment threshold associated with data indicative of the electrical property when the first needle 106 and/or the second needle 110 are within the skin of the patient. Additionally or alternatively, the threshold can be a detached threshold associated with data indicative of the electrical property⁷ when the first needle 106 and/or the second needle 110 are detached from/not within the skin. Additionally or alternatively, the threshold can be one or more semi-attached threshold associated with data indicative of the electrical property when the first needle 106 and/or the second needle 110 are in one or more states of semi-attachment with the ski n/parti al ly within the skin.

[0052] Based upon the results of the determinations at steps 1004, 1006, and 1008, the process 1000 can determine a state of attachment at one of steps 1010, 1012, and 1014. For example, in the embodiment shown in FIG. 10, if at steps 1004 and 1006 the electrical property of each of the first needle 106 and the second needle 1 10 are outside of an attachment threshold, the process 1000 can determine, at step 1010, that the needle array 100 is in a detached state. If at step 1004 the electrical property of the first needle 106 is not outside of an attachment threshold and at step 1006 the electrical property of the second needle 110 is outside of an attachment threshold, the process 1000 can determine, at step 1012, that the needle array⁷ 100 is in a semi-attached state. Similarly, if at step 1004 the electrical property⁷ of the first needle 106 is outside of an attachment threshold and at step 1008 the electrical property of the second needle 110 is not outside of an attachment threshold, the process 1000 can determine, at step 1012, that the needle array 100 is in the semi-attached state. If at steps 1004 and 1006 the electrical property of each of the first needle 106 and the second needle 110 are not outside of an attachment threshold, the process 1000 can determine, at step 1014, that the needle array 100 is in an attached state.

[0053] The needle arrays described throughout this disclosure can be used to identify and quantify a dynamic process of detachment from the skin. In some aspects, the needle array attached to the skin can become detached or partially detached during use. In some aspects, one side of the needle array may become detached or partially detached, while another side is still attached or partially attached to the skin. It may be advantageous to identify when such detachment occurs and the rate at which detachment is occurring. This information can be used to modulate delivery⁷ of the medicament, as described previously. For example, the needle array 100 may be in the attached state at a first time Tl. Some or all of the needles (e.g., first needles 106, second needles 110, or third needles 114) can move from an attached, or a fully attached, configuration to a detached or a semi-attached configuration at a second time T2. Thus, the needle array 100 can transition from the attached state at the first time Tl to a different state (e.g., detached state, first semi-attached state, or second semi-attached state) at the second time T2. Similarly, if the needle array 100 is in the first semi-attached state at Tl, the needle array 100 can move to a state of lesser attachment (e.g., the second semi-attached state or the detached state) at the second time T2. The needle array 100 can be moved to further states as time progresses. For example, the needle array- 100 can be in the attached state at the first time Tl, move to the first semi-attached state at the second time T2, and further transition to the second semi-attached state or to a detached state at a third time T3. The electrical parameters measured within the needle array 100 can be used to not only identify⁷ which state the needle array 100 is in as described throughout this disclosure, but also to quantify the duration that the needle array 100 spends in each of its states. The electrical parameters can be used to calculate the time that has passed between transitions from one state to another to identify the rate of detachment of the needle array 100 over a set timeframe (e.g., a timeframe that includes Tl, T2, T3, and any other number of time points). The calculation can be based on the measured electrical parameters of each type of needle within the needle array 100 or on each individual needle within the needle array 100. It should be appreciated that this disclosure can be used with needles arrays 200 or 300 as well and is not limited to the needle array 100.

[0054] FIG. 11 shows an example process 1100 for calculating a rate of detachment of the needle array 100. In step 1102, the initial attachment state of the needle array 100 is determined based on measurement of the electrical parameters as described throughout this disclosure. The time that this identification occurs can be recorded (e g., as a first time Tl). At this step, the needle array 100 can be attached to the skin and medicament can be administered to the patient through the needles. In some aspects, the needle array 100 at the step 1102 can be in the attached state, although it will be understood that the needle array 100 can also be in the first semi-attached state or in the second semi-attached state. [0055] After the attachment state and time point are identified in step 1102, the needle array 100 can be monitored, in step 1104, to identify if and when the attachment state changes. The monitoring may be controlled by the control system 120 or similar component. If there is a change in attachment state, the process can split into two branches. As shown in the decision block 1106, the process 1100 can identify' if there has been a change in attachment. If there is no change, the process 1100 can continue monitoring per step 1104. If there is a change in attachment state, the process 1100 can move to step 1108. In step 1108, the new attachment state can be identified using the concepts described throughout this disclosure, and a subsequent time point is recorded (e.g., a second time T2). The difference between the time point of the changed attachment state in step 1108 and the previous attachment state of step 1102 can be calculated to quantify the period that the needle array 100 was in the previous attachment state identified in step 1102.

[0056] It should be appreciated that the process 1100 can repeat steps 1104 to 1108 for the duration of use of the needle array 100, for a preset time duration, or until the needle array 100 is identified as being in a predetermined attachment state (e.g., the detached state). With each subsequent cycle of steps 1104 to 1108, the process 1100 can append subsequent time period measurements (e.g., T3, T4, etc.).

[0057] In embodiments, the process 1100 can include an optional step (not shown) of changing the parameters of medicament delivery based on the attachment state of the needle array 100 and/or on the calculated times between different attachment states. It should be understood that the process 1 1 0 can be used with and/or used to determine a rate of detachment of any of the needle arrays described herein including any embodiments of the needle arrays 100, 200, or 300 described previously.

[0058] It will be appreciated that the foregoing description provides examples of the invention. However, it is contemplated that other implementations of the invention may differ in detail from the foregoing examples. All references to the invention or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the invention more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the invention entirely unless otherwise indicated. Unless expressly indicated to the contrary', all ranges disclosed in this disclosure are inclusive in that they include the end points of the ranges as well as all points between the end points.

Claims

What is claimed is:

1. A needle array configured to sense an electrical property, the needle array comprising: a substrate; a first needle projecting from a surface of the substrate, the first needle comprising a first feature spaced a first distance from the surface of the substrate, the first needle being configured to sense the electrical property when the first feature is inserted into skin; and a second needle projecting from the surface of the substrate, the second needle comprising a second feature spaced a second distance from the surface of the substrate, the second needle being configured to sense the electrical property when the second feature is inserted into the skin; wherein the second distance is different from the first distance.

2. The needle array of claim 1, wherein the second distance is less than the first distance.

3. The needle array of claim 1, wherein: the first needle is longer than the second needle, the first feature is a tip of the first needle, and the second feature is a tip of the second needle.

4. The needle array of claim 1, wherein: the first needle and the second needle each comprise a tip, and the first needle and the second needle are each segmented into at least a first segment including the tip and a second segment that is proximal of the first segment, the second segment being more conductive than the first segment.

5. The needle array of claim 4, wherein: the first feature is the first segment of the first needle, and the second feature is the second segment of the first needle.

6. The needle array of claim 5, wherein: the first distance extends from the surface of the substrate to the tip of the first needle, and the second distance extends from the surface of the substrate to a distal edge of the second segment.

7. The needle array of claim 4, wherein: the first segment of each of the first needle and the second needle is coated with a first coating, and the second segment of each of the first needle and the second needle is coated with a second coating having a conductivity' greater than the first coating.

8. The needle array of claim 1, wherein the second distance is between 150 gm and 300 gm less than the first distance.

9. The needle array of claim 1, wherein: the first distance is at least 600 gm, and the second distance is between 300 gm and 450 gm.

10. The needle array of claim 1, further comprising a third needle projecting from the surface of the substrate, the third needle comprising a third feature spaced a third distance from the surface of the substrate, and the third needle being configured to sense the electrical property⁷ when the third feature is inserted into the skin, wherein the third distance is different from the first distance and the second distance.

11. The needle array of claim 10, wherein the third distance is at least 150 pm less than the second distance.

12. The needle array of claim 1, wherein the electrical property is at least one of impedance, resistance, or capacitance.

13. A sensor comprising: a needle array configured to sense an electrical property, the needle array comprising: a substrate; a first needle projecting from a surface of the substrate, the first needle comprising a first feature spaced a first distance from the surface of the substrate, the first needle being configured to sense the electrical property when the first feature is inserted into skin; a second needle projecting from the surface of the substrate, the second needle comprising a second feature spaced a second distance from the surface of the substrate, the second distance being different from the first distance, and the second needle being configured to sense the electrical property when the second feature is inserted into the skin; and a control system operatively connected to the needle array, the control system being configured to: receive data indicative of the electrical property from the first needle and the second needle, and determine, based on the data indicative of the electrical property', a state of attachment of the needle array to a surface of the skin.

14. The sensor of claim 13. wherein the control system is configured to determine that the state of attachment of the needle array to the surface of the skin is a semi -attached state based on i) the data indicative of the electrical property' of the first needle being outside of a threshold associated with the first feature, or ii) the data indicative of the electrical property of the second needle being outside of a threshold associated with the second feature.

15. The sensor of claim 13, wherein the control system is configured to determine that the state of attachment of the needle array to the surface of the skin is an attached state based on i) the data indicative of the electrical property of the first needle being outside of a threshold associated with the first feature, and ii) the data indicative of the electrical property of the second needle being outside of a threshold associated with the second feature.

16. The sensor of claim 13, wherein the control system is configured to determine that the state of attachment of the needle array to the surface of the skin is a detached state based on i) the data indicative of the electrical property of the first needle being above a threshold associated with the first feature, and ii) the data indicative of the electrical property' of the second needle being above a threshold associated with the second feature.

17. The sensor of claim 13. wherein the second distance is less than the first distance.

18. The sensor of claim 13, wherein: the first needle is longer than the second needle, the first feature is a tip of the first needle, and the second feature is a tip of the second needle.

19. The sensor of claim 13, wherein: the first needle and the second needle each comprise a tip. and the first needle and the second needle are each segmented into at least a first segment including the tip and a second segment that is proximal of the first segment, the second segment being more conductive than the first segment.

20. The sensor of claim 19, wherein: the first feature is the first segment of the first needle, and the second feature is the second segment of the first needle.

21. The sensor of claim 20, wherein: the first distance extends from the surface of the substrate to the tip of the first needle, and the second distance extends from the surface of the substrate to a distal edge of the second segment.

22. The sensor of claim 19, wherein: the first segment of each of the first needle and the second needle is coated with a first coating, and the second segment of each of the first needle and the second needle is coated with a second coating having a conductivity greater than the first coating.

23. The sensor of claim 13, wherein the needle array is configured to transition from the first state of attachment to a second state of attachment during a period of time, and the control system is configured to: determine that the needle array is in the first state of attachment; assign, in response to the determination that the needle array is in the first state of attachment, a first time within the period of time; determine that the needle array is in the second state of attachment; assign, in response to the determination that that the needle array is in the second state of attachment, a second time value within the period of time; and calculate the difference between the second time and the first time.