WO2023183440A1

WO2023183440A1 - Flexible skin sensors for skin hydration measurements

Info

Publication number: WO2023183440A1
Application number: PCT/US2023/015984
Authority: WO
Inventors: Henry Kin Heng Pang; Yoshiaki Kito; Fardad Ali Hashemi
Original assignee: Nikon Corporation
Priority date: 2022-03-23
Filing date: 2023-03-22
Publication date: 2023-09-28

Abstract

The problem of inconvenient, inaccurate measurement of hydration of the stratum corneum (SC) skin layer is addressed by systems and methods that employ two-dimensional, tightly-spaced arrays of surface electrodes fabricated on a flexible substrate. The systems and methods generally utilize a plurality of cathodes and a plurality of anodes arranged in first and second arrays, respectively, on a flexible substrate. The plurality of cathodes and the plurality of anodes are arranged to form a plurality of anode-cathode pairs. The cathodes and the anodes are electrically coupled to a plurality of cathode electrical leads and a plurality of anode electrical leads, respectively. A controller is electrically coupled to the plurality of cathode electrical leads and the plurality of anode electrical leads and configured to measure a plurality of impedances or conductances between the plurality of cathode-anode pairs.

Description

FLEXIBLE SKIN SENSORS FOR SKIN HYDRATION MEASUREMENTS

CROSS-REFERENCE

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63/322,737, filed on March 23, 2022, entitled “FLEXIBLE SKIN SENSORS FOR SKIN HYDRATION MEASUREMENTS,” which application is incorporated herein by reference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

[0002] Determination of the moisture content of skin, and especially of the stratum comeum (SC) layer of skin, is very important in the fields of cosmetology and dermatology. Prior work in the study of skin hydration has relied on the observation that human skin has resistive and capacitive characteristics when subjected to small amounts of alternating current (AC) and that skin impedance (resistance and capacitive reactance) varies with AC frequency. Moreover, the skin impedance changes substantially depending on its hydration level. Thus, skin conductance (the reciprocal of skin resistance) may be a suitable parameter for describing skin hydration. While numerous systems have been proposed for measuring skin conductance to determine skin hydration, the systems generally suffer from numerous shortcomings. First, they generally use electrodes that are rigid and inflexible, causing poor contact with the skin. Second, they generally require very precise contact forces with the skin to obtain repeatable measurements, which limits their use by consumers who may not be able to precisely and accurately apply such contact forces to the skin. Third, they generally require a few seconds to a few minutes to obtain a single measurement, limiting their utility in obtaining fine-grained time series measurements. Fourth, they generally require the user to remain stationary, which may be awkward or uncomfortable for some users. Fifth, they are generally expensive (on the order of a few thousand dollars), limiting their adoption by home users. Sixth, they generally feature electrodes that are not properly sized to obtain measurements from the SC layer. Accordingly, presented herein are systems for more convenient and accurate measurement of hydration of the SC skin layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings.

[0004] FIG. 1 shows a schematic depicting a first exemplary system for measuring impedances or conductances.

[0005] FIG. 2A shows a schematic depicting a first exemplary cathode-anode pair for use with the system of FIG. 1.

[0006] FIG. 2B shows a schematic depicting a second exemplary cathode-anode pair for use with the system of FIG. 1.

[0007] FIG. 2C shows a schematic depicting a third exemplary cathode-anode pair for use with the system of FIG. 1.

[0008] FIG. 3 shows a schematic depicting a second exemplary system for measuring impedances or conductances.

[0009] FIG. 4A shows a schematic depicting a cross-sectional view of a system for measuring impedances or conductances consisting of cathodes, anodes, cathode electrical leads, and anode electrode leads arranged on a single metallic layer.

[0010] FIG. 4B shows a schematic depicting a top view of the system of FIG. 4A.

[0011] FIG. 5 shows a schematic depicting a cross-sectional view of a system for measuring impedances or conductances consisting of cathodes and cathode electrical leads arranged on a first metallic layer and anodes and anode electrical leads arranged on a second metallic layer.

[0012] FIG. 6 shows a schematic depicting a cross-sectional view of a system for measuring impedances or conductances consisting of cathodes arranged on a first metallic layer, anodes and anode electrical leads arranged on a second metallic layer, and cathode electrical leads arranged from the first metallic layer to the second metallic layer by vias. [0013] FIG. 7A shows a schematic depicting a top view of a system for measuring impedances or conductances consisting of cuts surrounding cathode-anode pairs.

[0014] FIG. 7B shows a schematic depicting a top view of cathodes, anodes, cathode electrical leads, and anode electrical leads associated with the system of FIG. 7A.

[0015] FIG. 7C shows a schematic depicting a top view of cuts associated with the system of FIG. 7A.

DETAILED DESCRIPTION

[0016] The invention can be implemented in numerous ways, including as a process; an apparatus; a system; a composition of matter; a computer program product embodied on a computer readable storage medium; and/or a processor, such as a processor configured to execute instructions stored on and/or provided by a memory coupled to the processor. In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the invention. Unless stated otherwise, a component such as a processor or a memory described as being configured to perform a task may be implemented as a general component that is temporarily configured to perform the task at a given time or a specific component that is manufactured to perform the task. As used herein, the term “processor” refers to one or more devices, circuits, and/or processing cores configured to process data, such as computer program instructions.

[0017] A detailed description of one or more embodiments of the invention is provided below along with accompanying Figures (also, “FIGs.”) that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

[0018] As used herein, the term “or” shall convey both disjunctive and conjunctive meanings. For instance, the phrase “A or B” shall be interpreted to include element A alone, element B alone, and the combination of elements A and B.

[0019] In the Figures, like numbers shall refer to like elements.

[0020] Skin hydration monitoring is very important in the fields of cosmetology and dermatology. Cosmetology concerns the study and application of beauty products such as moisturizers, and skin hydration monitoring is the primary way to assess the effectiveness of moisturization and anti-aging skin treatments. Dermatology concerns the diagnosis and treatment of skin disorders. It also relies on skin hydration monitoring to assess treatment for disorders such as eczema and psoriasis, which are typically characterized by abnormally dry skin.

[0021] The skin is the largest human external organ and is composed of three main layers. The epidermis is the first layer starting from the surface of the skin. Within the epidermis, the first sub-layer is called the stratum corneum (SC) layer or “homy layer”, which functions to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress. Beneath the SC layer, the other sub-layers are called stratum lucidum, stratum granulosum, stratum spinosum and stratum basale. Moreover, beneath the epidermis layer the other two main layers are called dermis and hypodermis respectively.

[0022] The characterization of “healthy skin” may look at a number of parameters including texture, color and hydration. Skin hydration typically refers to the water content of the SC layer and not deeper layers of the skin. Generally speaking, properly hydrated skin appears smooth and firm to the touch. Conversely, SC layer appears scaly and uneven to the touch when it is dry.

[0023] Prior work in the study of skin hydration has relied on the observation that human skin has resistive and capacitive characteristics when subjected to small amounts of alternating current (AC) and that skin impedance (resistance and capacitive reactance) varies with AC frequency. Moreover, the skin impedance changes substantially depending on its hydration level. Thus, skin conductance (the reciprocal of skin resistance) may be a suitable parameter for describing skin hydration.

[0024] While numerous systems have been proposed for measuring skin conductance to determine skm hydration, the systems generally suffer from numerous shortcomings. First, they generally use electrodes that are rigid and inflexible, causing poor contact with the skin. Second, they generally require very precise contact forces with the skin to obtain repeatable measurements, which limits their use by consumers who may not be able to precisely and accurately apply such contact forces to the skin. Third, they generally require a few seconds to a few minutes to obtain a single measurement, limiting their utility in obtaining finegrained time series measurements. Fourth, they generally require the user to remain stationary, which may be awkward or uncomfortable for some users. Fifth, they are generally expensive (on the order of a few thousand dollars), limiting their adoption by home users. Sixth, they generally feature electrodes that are not properly sized to obtain measurements from the SC layer.

[0025] Accordingly, the problem of inconvenient, inaccurate measurement of hydration of the SC skin layer is addressed by systems and methods that employ two- dimensional, tightly-spaced arrays of surface electrodes fabricated on a flexible substrate. The systems and methods generally utilize a plurality of cathodes and a plurality of anodes arranged in first and second arrays, respectively, on a flexible substrate. The plurality of cathodes and the plurality of anodes are arranged to form a plurality of anode-cathode pairs. The cathodes and the anodes are electrically coupled to a plurality of cathode electrical leads and a plurality of anode electrical leads, respectively. A controller is electrically coupled to the plurality of cathode electrical leads and the plurality of anode electrical leads and configured to measure a plurality of impedances or conductances between the plurality of cathode-anode pairs.

[0026] A system for measuring impedances or conductances is disclosed herein. The system generally comprises: a flexible substrate; a plurality of cathodes arranged in a first array on the flexible substrate; a plurality of anodes arranged in a second array on the flexible substrate, each anode of the plurality of anodes located in proximity to a cathode of the plurality of cathodes, thereby forming a plurality of cathode-anode pairs; a plurality of cathode electrical leads electrically coupled to the plurality of cathodes; a plurality of anode electrical leads electrically coupled to the plurality of anodes; and a controller electrically coupled to the plurality of cathode electrical leads and electrically coupled to the plurality of anode electrical leads and configured to measure a plurality of impedances or conductances, each impedance or conductance of the plurality of impedances or conductances corresponding to a cathode-anode pair of the plurality of cathode-anode pairs. In some embodiments, the flexible substrate is selected from the group consisting of: polyimide, silicone, polyethylene terephthalate (PET), polydimethylsiloxane (PDMS), and any combination thereof. In some embodiments, each cathode of the plurality of cathodes has a circular, ellipsoidal, square, or rectangular shape. In some embodiments, each anode of the plurality of anodes has a circular, ellipsoidal, square, or rectangular shape. In some embodiments, each anode of the plurality of anodes substantially surrounds a cathode of the plurality of cathodes or each cathode of the plurality of cathodes substantially surrounds an anode of the plurality of anodes. In some embodiments, each anode of the plurality of anodes entirely surrounds a cathode of the plurality of cathodes or each cathode of the plurality of cathodes entirely surrounds an anode of the plurality of anodes. In some embodiments, each anode of the plurality of anodes is arranged to substantially face a cathode of the plurality of cathodes. In some embodiments, the first array comprises a rectangular array. In some embodiments, the second array comprises a rectangular array. In some embodiments, the plurality of cathode electrical leads comprise a first plurality of electrical traces arranged to electrically couple a first plurality of rows of cathodes or a first plurality of columns of cathodes. In some embodiments, the plurality of anode electrical leads comprise a second plurality of electrical traces arranged to electrically couple a second plurality of columns of anodes or a second plurality of rows of anodes. In some embodiments, the controller comprises: (i) a first multiplexer configured to select a first row of the first plurality of rows or a first column of the first plurality of columns and (ii) a second multiplexer configured to select a second column of the second plurality of columns or a second row of the second plurality of rows. In some embodiments, the controller is configured to measure an impedance or conductance between a cathode-anode pair of the plurality of cathode-anode pairs that is located at a location defined by the first row and the second column or by the first column and the second row. In some embodiments, the plurality of cathode electrical leads further comprise a third plurality of electrical traces arranged to electrically couple the first plurality of rows of cathodes or the first plurality of columns of cathodes. In some embodiments, the plurality of anode electrical leads further comprise a fourth plurality of electrical traces arranged to electrically couple the second plurality of columns of anodes or the second plurality of rows of anodes. In some embodiments, the plurality of cathodes or the plurality of anodes are formed from a first metallic layer located on the flexible substrate. In some embodiments, the system further comprises an insulating layer located above the first metallic layer. In some embodiments, the insulating layer is selected from the group consisting of: crosslinked SU-8 photoresist, polyimide, silicone, polyethylene terephthalate (PET), poly dimethylsiloxane (PDMS), and any combination thereof. In some embodiments, the plurality of cathodes or the plurality of anodes are formed from a second metallic layer located above the insulating layer. In some embodiments, the plurality of cathode electrical leads or the plurality of anode electrical leads are formed from the first metallic layer. In some embodiments, the plurality of cathode electrical leads or the plurality of anode electrical leads are formed from the second metallic layer. In some embodiments, the system further comprises a plurality of vias configured to electrically couple the plurality of cathode electrical leads from the first metallic layer to the second metallic layer or to electrically couple the plurality of anode electrical leads from the first metallic layer to the second metallic layer. In some embodiments, each cathode electrical lead of the plurality of cathode electrical leads is electrically coupled to a single cathode of the plurality of cathodes. In some embodiments, each anode electrical lead of the plurality of anode electrical leads is electrically coupled to a single anode of the plurality of anodes. In some embodiments, the flexible substrate comprises a plurality of cuts configured to allow the flexible substrate to further bend when adhered to a surface. In some embodiments, each cut of the plurality of cuts is located in proximity to a cathode of the plurality of cathodes or to an anode of the plurality of anodes. In some embodiments, each cut of the plurality of cuts substantially surrounds a cathode of the plurality of cathodes or an anode of the plurality of anodes. In some embodiments, each cut of the plurality of cuts is located in proximity to a cathode electrical lead of the plurality of cathode electrical leads or to an anode electrical lead of the plurality of anode electrical leads. In some embodiments, each cut of the plurality of cuts substantially surrounds a cathode electrical lead of the plurality of cathode electrical leads or an anode electrical lead of the plurality of anode electrical leads. In some embodiments, each cut surrounds a percentage of the circumference, perimeter, or area of the cathode electrical lead or the anode electrical lead that is within a range defined by any two of the preceding values. In some embodiments, each cathode-anode pair of the plurality of cathode-anode pairs comprises a cathode of the plurality of cathodes located at least 10 micrometers (pm) from an anode of the plurality of anodes. In some embodiments, each cathode-anode pair of the plurality of cathode-anode pairs comprises a cathode of the plurality of cathodes located at most 100 pm from an anode of the plurality of anodes. In some embodiments, each cathode-anode pair of the plurality of cathode-anode pairs is located at least 1 pm from all other cathode-anode pairs of the plurality of cathode-anode pairs. In some embodiments, each cathode-anode pair of the plurality of cathode-anode pairs is located at most 10 millimeters (mm) from all other cathode-anode pairs of the plurality of cathode-anode pairs.

[0027] FIG. 1 shows a schematic depicting a first exemplary system 100 for measuring impedances or conductances. In the example shown, the system comprises a flexible substrate 110. In some embodiments, the flexible substrate is selected from the group consisting of: polyimide, silicone, polyethylene terephthalate (PET), poly dimethylsiloxane (PDMS), and any combination thereof.

[0028] In the example shown, the system comprises a plurality of cathodes 120 arranged in a first array on the flexible substrate. In some embodiments, the first array comprises at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, or more cathodes. In some embodiments, the first array comprises at most about 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 cathodes. In some embodiments, the first array comprises a number of cathodes that is within a range defined by any two of the preceding values. In the example shown, the first array comprises a rectangular array. In some embodiments, the first array comprises a regular or ordered array. In some embodiments, the first array comprises an irregular or disordered array.

[0029] In the example shown, the system comprises a plurality of anodes 130 arranged in a second array on the flexible substrate. In some embodiments, each anode of the plurality of anodes is located in proximity to a cathode of the plurality of cathodes. In some embodiments, the plurality of cathodes and the plurality of anodes form a plurality of cathode-anode pairs. In some embodiments, the second array comprises at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, or more anodes. In some embodiments, the second array comprises at most about 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 anodes. In some embodiments, the second array comprises a number of anodes that is within a range defined by any two of the preceding values. In the example shown, the second array comprises a rectangular array. In some embodiments, the second array comprises a regular or ordered array. In some embodiments, the second array comprises an irregular or disordered array.

[0030] In some embodiments, each cathode-anode pair comprises a cathode located a distance from an anode. In some embodiments, the distance is at least about 1 micrometer (pm), 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, 100 pm, 200 pm, 300 pm, 400 pm, 500 pm, 600 pm, 700 pm, 800 pm, 900 pm, 1 millimeter (mm), or more. In some embodiments, the distance is at most about 1 mm, 900 pm, 800 pm, 700 pm, 600 pm, 500 pm, 400 pm, 300 pm, 200 pm, 100 pm, 90 pm, 80 pm, 70 pm, 60 pm, 50 pm, 40 pm, 30 pm, 20 pm, 10 pm, 9 pm, 8 pm, 7 pm, 6 pm, 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, or less. In some embodiments, the distance is within a range defined by any two of the preceding values.

[0031] In some embodiments, each cathode-anode pair is located a distance from all other cathode-anode pairs. In some embodiments, the distance is at least about 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, 100 pm, 200 pm, 300 pm, 400 pm, 500 pm, 600 pm, 700 pm, 800 pm, 900 pm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or more. In some embodiments, the distance is at most about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 900 pm, 800 pm, 700 pm, 600 pm, 500 pm, 400 pm, 300 pm, 200 pm, 100 pm, 90 pm, 80 pm, 70 pm, 60 pm, 50 pm, 40 pm, 30 pm, 20 pm, 10 pm, 9 pm, 8 pm, 7 pm, 6 pm, 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, or less. In some embodiments, the distance is within a range defined by any two of the preceding values.

[0032] In the example shown, the system comprises a plurality of cathode electrical leads 140. In some embodiments, the plurality of cathode electrical leads are electrically coupled to the plurality of cathodes. In the example shown, each cathode is electrically coupled to a single cathode electrical lead. In the example shown, each cathode electrical lead is depicted as having a curved shape or form. However, each cathode electrical lead may have any shape or form. In some embodiments, the curved shape or form increases the ability of each cathode electrical lead to resist damage when the flexible substrate is bent or otherwise deformed.

[0033] In some embodiments, the plurality of cathode electrical leads comprise a first plurality of electrical traces. In the example shown, the first plurality of electrical traces is configured to electrically couple a first plurality of rows of cathodes. That is, in the example shown, the first plurality of electrical traces are arranged to electrically couple cathodes that he in a row within the first array, thereby forming a plurality of rows of electrically coupled cathodes. In some embodiments, the first plurality of electrical traces is configured to electrically couple a first plurality of columns of cathodes. That is, in some embodiments, the first plurality of electrical traces are arranged to electrically couple cathodes that lie in a column within the first array, thereby forming a plurality of columns of electrically coupled cathodes.

[0034] In the example shown, the system comprises a plurality of anode electrical leads 150. In some embodiments, the plurality of anode electrical leads are electrically coupled to the plurality' of anodes. In the example shown, each anode is electrically coupled to a single anode electrical lead. In the example shown, each anode electrical lead is depicted as having a curved shape or form. However, each anode electrical lead may have any shape or form. In some embodiments, the curved shape or form increases the ability of each anode electrical lead to resist damage when the flexible substrate is bent or otherwise deformed. [0035] In some embodiments, the plurality of anode electrical leads comprise a second plurality of electrical traces. In the example shown, the second plurality of electrical traces is configured to electrically couple a second plurality of columns of anodes. That is, in the example shown, the second plurality of electrical traces are arranged to electrically couple anodes that lie in a column within the second array, thereby forming a plurality of columns of electrically coupled anodes. In some embodiments, the second plurality of electrical traces is configured to electrically couple a second plurality of rows of anodes. That is, in some embodiments, the second plurality of electrical traces are arranged to electrically couple anodes that lie in a row along the first array, thereby forming a plurality of rows of electrically coupled anodes.

[0036] In the example shown, the system comprises a controller 160. In some embodiments, the controller is electrically coupled to the plurality of cathode electrical leads. In some embodiments, the controller is electrically coupled to the plurality of anode electrical leads. In some embodiments, the controller is configured to measure a plurality of impedances or conductances. In some embodiments, each impedance or conductance corresponds to a cathode-anode pair of the plurality of cathode-anode pairs. In some embodiments, the controller is configured to measure at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, or more impedances or conductances. In some embodiments, the controller is configured to measure at most about 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 conductances. In some embodiments, the controller is configured to measure the plurality of impedances or conductances in parallel. In some embodiments, the controller is configured to measure the plurality of impedances or conductances sequentially.

[0037] In some embodiments, the controller comprises a first multiplexer 162. In some embodiments, the first multiplexer is configured to select a first row of the first plurality of rows (if the cathodes are arranged in rows, as described herein). In some embodiments, the first multiplexer is configured to select a first column of the first plurality of columns (if the cathodes are arranged in columns, as described herein). In some embodiments, the controller comprises a second multiplexer 164. In some embodiments, the second multiplexer is configured to select a second column of the second plurality of columns (if the anodes are arranged in columns, as described herein). In some embodiments, the second multiplexer is configured to select a second row of the second plurality of rows (if the anodes are arranged in rows, as described herein). In some embodiments, the controller is configured to measure an impedance or a conductance between a cathode-anode pair that is located at a location defined by the first row and the second column. In some embodiments, the controller is configured to measure an impedance or a conductance between a cathodeanode pair that is located at a location defined by the first column and the second row. In this manner, the controller may measure impedances or conductances associated with cathodeanode pairs at specific locations.

[0038] FIG. 2A shows a schematic depicting a first exemplary cathode-anode pair 200a for use with the system 100. In the example shown, the cathode 210a and the anode 220a have closed circular shapes. However, the cathode or the anode may have any closed shape. In some embodiments, the cathode or the anode have a closed polygonal or closed curvilinear shape. In some embodiments, the cathode or the anode have a closed circular, ellipsoidal, square, or rectangular shape. In the example shown, the anode entirely surrounds the cathode. However, the cathode may entirely surround the anode.

[0039] FIG. 2B shows a schematic depicting a second exemplary cathode-anode pair 200b for use with the system 100. In the example shown, the cathode 210b and the anode 220b have open circular shapes. However, the cathode or the anode may have any open shape. In some embodiments, the cathode or the anode have an open polygonal or open curvilinear shape. In some embodiments, the cathode or the anode have an open circular, ellipsoidal, square, or rectangular shape. In the example shown, the anode partially surrounds the cathode. However, the cathode may partially surround the anode. In some embodiments, the anode substantially surrounds the cathode. In some embodiments, the anode surrounds at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of a circumference, perimeter, or area of the cathode. In some embodiments, the anode surrounds at most about 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or less of the circumference, perimeter, or area of the cathode. In some embodiments, the anode surrounds a percentage of the circumference, perimeter, or area of the cathode that is within a range defined by any two of the preceding values. In some embodiments, the cathode substantially surrounds the anode. In some embodiments, the cathode surrounds at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of a circumference, perimeter, or area of the anode. In some embodiments, the cathode surrounds at most about 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or less of the circumference, perimeter, or area of the anode. In some embodiments, the cathode surrounds a percentage of the circumference, penmeter, or area of the anode that is within a range defined by any two of the preceding values.

[0040] FIG. 2C shows a schematic depicting a third exemplary cathode-anode pair 200c for use with the system 100. In the example shown, the cathode 210c and the anode 220c have closed rectangular shapes. How ever, the cathode or the anode may have any shape described herein. In the example shown, the cathode and the anode substantially face one another. However, the cathode and the anode may be arranged at an angle with respect to one another.

[0041] Returning to the description of FIG. 1, in some embodiments, the cathodes 120 comprise any of the cathodes 210a, 210b, and 210c described herein with respect to FIGs. 2A-2C. In some embodiments, the anodes 130 comprise any of the anodes 220a, 220b, and 220c described herein with respect to FIGs. 2A-2C.

[0042] FIG. 3 shows a schematic depicting a second exemplary system 300 for measuring impedances or conductances. In the example shown, the system 300 comprises the flexible substrate 110, the plurality of cathodes 120, the plurality of anodes 130, the plurality of cathode electrical leads 140, the plurality of anode electrical leads 150, the controller 160, the first multiplex 162, and the second multiplexer 164 described herein with respect to FIG. 1.

[0043] In comparison with the first system 100 described herein with respect to FIG. 1, the second system 300 electrically couples multiple cathode electrical leads to each cathode and multiple anode electrical leads to each anode. In some embodiments, such multiple connections decrease the likelihood of failure of each cathode and anode. [0044] In the example shown, the plurality of cathode electrical leads further comprises a third plurality of electrical traces (in addition to the first plurality' of electrical traces described herein with respect to FIG. 1). In the example shown, the first and third pluralities of electrical traces are configured to electrically couple the first plurality of rows of cathodes. That is, in the example shown, the first and third pluralities of electrical traces are arranged to electrically couple cathodes that lie in a row within the first array, thereby forming a plurality of rows of electrically coupled cathodes. In some embodiments, the first and third pluralities of electrical traces is configured to electrically couple a first plurality of columns of cathodes. That is, in some embodiments, the first and third pluralities of electrical traces are arranged to electrically couple cathodes that lie in a column within the first array, thereby forming a plurality of columns of electrically coupled cathodes.

[0045] In the example shown, the plurality' of anode electrical leads further comprises a fourth plurality of electrical traces (in addition to the second plurality of electrical traces described herein with respect to FIG. 1). In the example show n, the second and fourth pluralities of electrical traces are configured to electrically couple the second plurality of columns of anodes. That is, in the example shown, the second and fourth pluralities of electrical traces are arranged to electrically couple anodes that lie in a column within second array, thereby forming a plurality of columns of electrically coupled anodes. In some embodiments, the second and fourth pluralities of electrical traces is configured to electrically couple a second plurality of rows of anodes. That is, in some embodiments, the second and fourth pluralities of electrical traces are arranged to electrically couple anodes that lie in a row within the second array, thereby forming a plurality' of rows of electrically coupled anodes.

[0046] Although the system 300 depicts each cathode as electrically coupled to two cathode electrical leads, and each anode as electrically coupled to two anode electrical leads, the disclosure is not so limited. Each cathode may be electrically coupled to any number of cathode electrical leads and each anode may be electrically coupled to any number of anode electrical leads. In some embodiments, each cathode is electrically coupled to at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more cathode electrical leads. In some embodiments, each cathode is electrically coupled to at most 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 cathode electrical leads. In some embodiments, each cathode is electrically coupled to a number of cathode electrical leads that is within a range defined by any two of the preceding values. In some embodiments, each anode is electrically coupled to at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more anode electrical leads. In some embodiments, each anode is electrically coupled to at most 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 anode electrical leads. In some embodiments, each anode is electrically coupled to a number of anode electrical leads that is within a range defined by any two of the preceding values.

[0047] FIG. 4A shows a schematic depicting a cross-sectional view of a system 400 for measuring impedances or conductances consisting of cathodes, anodes, cathode electrical leads, and anode electrode leads arranged on a single metallic layer. In the example shown, the cross-sectional view is through a single row or column of cathodes or anodes. In some embodiments, the flexible substrate 110 supports the plurality of cathodes 120, the plurality of anodes 130, the plurality of cathode electrical leads 140, and the plurality of anode electrical leads 150. In some embodiments, the plurality of cathodes, the plurality of anodes, the plurality of cathode electrical leads, and the plurality of anode electrical leads are formed from a single metallic layer 410. In some embodiments, the single metallic layer comprises aluminum, copper, silver, gold, platinum, chrome, or any combination or alloy thereof. In some embodiments, the single metallic layer is adhered to the flexible substrate via an adhesion layer (not shown in FIG. 4A). In some embodiments, the single metallic layer is coated with an insulating layer 420.

[0048] FIG. 4B shows a schematic depicting a top view of the system 400. In the example shown, the plurality of cathode electrical leads 140 and the plurality of anode electrical leads 150 are arranged to avoid crossing. The system 400 may have the advantage of allowing both the plurality of cathode electrical leads and the plurality of anode electrical leads to be arranged on a single layer. In some embodiments, such an arrangement allows for easy coupling of the cathode electrical leads and the anode electrical leads to the controller (not shown in FIG. 4B).

[0049] FIG. 5 shows a schematic depicting a cross-sectional view of a system 500 for measuring impedances or conductances consisting of cathodes and cathode electrical leads arranged on a first metallic layer and anodes and anode electrical leads arranged on a second metallic layer. In the example shown, the cross-sectional view is through a single row or column of cathodes or anodes. In some embodiments, the flexible substrate 110 supports the plurality of cathodes 120, the plurality of anodes 130, the plurality of cathode electrical leads 140, and the plurality of anode electrical leads 150. In some embodiments, the plurality of cathodes and the plurality of cathode electrical leads are formed from a first metallic layer 410. In some embodiments, the first metallic layer is coated with a first insulating layer 420. [0050] In some embodiments, the first insulating layer is coated with a second metallic layer 510. In some embodiments, the plurality of anodes and the plurality of anode electrical leads are formed from the second metallic layer. In some embodiments, the second metallic layer is located above the first insulating layer. In some embodiments, the second metallic layer comprises aluminum, copper, silver, gold, platinum, chrome, or any combination or alloy thereof. In some embodiments, the second metallic layer is coated with a second insulating layer 520.

[0051] Although system 500 depicts the cathodes and cathode electrical leads as formed from the first metallic layer, and the anodes and anode electrical leads as formed from the second metallic layer, the disclosure should not be construed as so limiting. In some embodiments, the anodes and the anode electrical leads are formed from the first metallic layer, and the cathodes and cathode electrical leads are formed from the second metallic layer.

[0052] In the example shown, the plurality of cathode electrical leads and the plurality of anode electrical leads are arranged on separate layers (the first metallic layer and the second metallic layer, respectively) and may thus cross (for instance, in the manner shown in FIGs. 1 or 3). The system 500 may have the advantage of allowing for reduced spacing between cathode-anode pairs, which may not be readily achievable using a singlelayer device.

[0053] FIG. 6 shows a schematic depicting a cross-sectional view of a system 600 for measuring impedances or conductances consisting of cathodes arranged on a first metallic layer, anodes and anode electrical leads arranged on a second metallic layer, and cathode electrical leads arranged from the first metallic layer to the second metallic layer by vias. In the example shown, the cross-sectional view is through a single row or column of cathodes or anodes. In some embodiments, the flexible substrate 110 supports the plurality of cathodes 120, the plurality of anodes 130, the plurality of cathode electrical leads 140, and the plurality of anode electrical leads 150.

[0054] In some embodiments, the plurality of cathodes are formed from a first metallic layer 410. In some embodiments, the first metallic layer is coated with a first insulating layer 420. In some embodiments, the first insulating layer is coated with a second metallic layer 510. In some embodiments, the plurality of anodes and the plurality of anode electrical leads are formed from the second metallic layer. In some embodiments, the second metallic layer is located above the first insulating layer. In some embodiments, the second metallic layer is coated with a second insulating layer 520.

[0055] In some embodiments, the plurality of cathode electrical leads are partially formed from the first metallic layer and the second metallic layer. In some embodiments, the plurality of cathode electrical leads are electrically coupled from the first metallic layer to the second metallic layer by a plurality of vias 610.

[0056] Although system 600 depicts the cathodes as formed from the first metallic layer, the anodes and anode electrical leads as formed from the second metallic layer, and the cathode electrical leads as electrically coupled from the first metallic layer to the second metallic layer by vias, the disclosure should not be construed as so limiting. In some embodiments, the anodes are formed from the first metallic layer, the cathode and cathode electrical leads are formed from the second metallic layer, and the anode electrical leads are electrically coupled from the first metallic layer to the second metallic layer by vias.

[0057] In the example shown, the plurality' of cathode electrical leads and the plurality of anode electrical leads are at least partially arranged on separate layers (the first metallic layer and the second metallic layer, respectively) and may thus cross(for instance, in the manner shown in FIGs. 1 or 3). The system 600 may have the advantage of allowing for lesser spacing between cathode-anode pairs. Moreover, the system 600 may have the advantage of allowing both the plurality of cathode electrical leads and the plurality of anode electrical leads to be at least partially arranged on a single layer. In some embodiments, such an arrangement allows for easy coupling of the cathode electrical leads and the anode electrical leads to the controller (not shown in FIG. 6B)

[0058] FIG. 7A shows a schematic depicting a top view of a system 700 for measuring impedances or conductances consisting of cuts surrounding cathode-anode pairs. In the example shown, the flexible substrate 110 supports the plurality of cathodes 120, the plurality of anodes 130, the plurality of cathode electrical leads 140, and the plurality of anode electrical leads 150. In some embodiments, the flexible substrate is broken by a plurality of cuts 710. In some embodiments, the plurality of cuts allows the flexible substrate to bend further than would otherwise be possible (for instance, when adhered to a surface). In some embodiments, the plurality of cuts penetrate through the entire thickness of the flexible substrate.

[0059] In some embodiments, each cut of the plurality of cuts is located in proximity to a cathode of the plurality of cathodes or in proximity to an anode of the plurality of anodes. In some embodiments, each cut is separated from a cathode or an anode by at least about 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, 100 pm, 200 pin, 300 pm, 400 pm, 500 pm, 600 pm, 700 pm, 800 pm, 900 pm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or more. In some embodiments, each cut is separated from a cathode or an anode by at most about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 900 pm, 800 pm, 700 pm, 600 pm, 500 pm, 400 pm, 300 pm, 200 pm, 100 pm, 90 pm, 80 pm, 70 pm, 60 pm, 50 pm, 40 pm, 30 pm, 20 pm, 10 pm, 9 pm, 8 pm, 7 pm, 6 pm, 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, or less. In some embodiments, each cut is separated from a cathode or an anode by a distance that is within a range defined by any two of the preceding values.

[0060] In some embodiments, each cut of the plurality of cuts substantially surrounds a cathode of the plurality of cathodes or an anode of the plurality of anodes. In some embodiments, each cut surrounds at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of a circumference, perimeter, or area of the cathode or the anode. In some embodiments, each cut surrounds at most about 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or less of the circumference, perimeter, or area of the cathode or the anode. In some embodiments, each cut surrounds a percentage of the circumference, perimeter, or area of the cathode or the anode that is within a range defined by any two of the preceding values. [0061] In some embodiment, each cut of the plurality of cuts is located in proximity to a cathode electrical lead of the plurality of cathode electrical leads or in proximity to an anode electrical lead of the plurality of anode electrical leads. In some embodiments, each cut is separated from a cathode electrical lead or an anode electrical lead by at least about 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, 100 pm, 200 pm, 300 pm, 400 pm, 500 pm, 600 pm, 700 pm, 800 pm, 900 pm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or more. In some embodiments, each cut is separated from a cathode electrical lead or an anode electrical lead by at most about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 900 pm, 800 pm, 700 pm, 600 pm, 500 pm, 400 pm, 300 pm, 200 pm, 100 pm, 90 pm, 80 pm, 70 pm, 60 pm, 50 pm, 40 pm, 30 pm, 20 pm, 10 pm, 9 pm, 8 pm, 7 pm, 6 pm, 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, or less. In some embodiments, each cut is separated from a cathode electrical lead or an anode electrical lead by a distance that is within a range defined by any two of the preceding values.

[0062] In some embodiments, each cut of the plurality of cuts substantially surrounds a cathode electrical lead of the plurality of cathode electrical leads or an anode electrical lead of the plurality of anode electrical leads. In some embodiments, each cut surrounds at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of a circumference, perimeter, or area of the cathode electrical lead or the anode electrical lead. In some embodiments, each cut surrounds at most about 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or less of the circumference, perimeter, or area of the cathode electrical lead or the anode electrical lead.

[0063] FIG. 7B shows a schematic depicting a top view of cathodes, anodes, cathode electrical leads, and anode electrical leads associated with the system 700. In the example shown, the cathode electrical leads 140 and the anode electrical leads 150 are arranged to allow the cuts to be made without severing any electrical connections.

[0064] FIG. 7C shows a schematic depicting a top view of cuts associated with the system 700. In the example shown, the cuts 710 avoid the cathode electrical leads and the anode electrical leads.

[0065] The arrangement of cathodes, anodes, cathode electrical leads, and anode electrical leads depicted in FIGs. 7A-7C is illustrative only. One having skill in the art will recognize that other arrangements are possible and within the scope of this disclosure.

[0066] The systems 100, 200a, 200b, 200c, 300, 400, 500, 600, and 700 presented herein with respect to FIGs. 1, 2A, 2B, 2C, 3, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, and 7C may be constructed using a variety or combination of microfabrication techniques. For example, the systems 100, 200a, 200b, 200c, 300, 400, 500, 600, and 700 may be constructed using thin film deposition, thick film deposition, chemical vapor deposition (CVD), atmospheric pressure CVD (APCVD), low-pressure CVD (LPCVD), ultrahigh vacuum CVD (UHVCVD), plasma enhanced CVD (PECVD), microwave plasma-assisted CVD (MPCVD), atomic layer CVD (ALCVD), physical vapor deposition (PVD), electron-beam PVD, cathodic arc deposition, evaporative deposition, pulsed laser deposition, sputter deposition, molecular beam epitaxy, photolithography, etching, wet etching, isotropic wet etching, anisotropic wet etching, dry etching, plasma etching, reactive-ion etching (RIE), deep RIE (DRIE), laser cutting, or any combination thereof.

RECITATION OF EMBODIMENTS

[0067] Embodiment I. A system comprising: a flexible substrate; a plurality of cathodes arranged in a first array on the flexible substrate; a plurality of anodes arranged in a second array on the flexible substrate, each anode of the plurality of anodes located in proximity to a cathode of the plurality of cathodes, thereby forming a plurality of cathodeanode pairs; a plurality of cathode electrical leads electrically coupled to the plurality of cathodes; a plurality of anode electrical leads electrically coupled to the plurality of anodes; and a controller electrically coupled to the plurality of cathode electrical leads and electrically coupled to the plurality of anode electrical leads and configured to measure a plurality of impedances or conductances, each impedance or conductance of the plurality of impedances or conductances corresponding to a cathode-anode pair of the plurality of cathode-anode pairs.

[0068] Embodiment 2. The system of Embodiment 1, wherein the flexible substrate is selected from the group consisting of: polyimide, silicone, polyethylene terephthalate (PET), poly dimethylsiloxane (PDMS), and any combination thereof.

[0069] Embodiment 3. The system of Embodiment 1 or 2, wherein each cathode of the plurality of cathodes has a circular, ellipsoidal, square, or rectangular shape.

[0070] Embodiment 4. The system of any one of Embodiments 1-3, wherein each anode of the plurality of anodes has a circular, ellipsoidal, square, or rectangular shape. [0071] Embodiment 5. The system of any one of Embodiments 1-4, wherein each anode of the plurality of anodes substantially surrounds a cathode of the plurality of cathodes or wherein each cathode of the plurality of cathodes substantially surrounds an anode of the plurality of anodes.

[0072] Embodiment 6. The system of Embodiment 5, wherein each anode of the plurality of anodes entirely surrounds a cathode of the plurality of cathodes or wherein each cathode of the plurality' of cathodes entirely surrounds an anode of the plurality of anodes. [0073] Embodiment 7. The system of any one of Embodiments 1-4, wherein each anode of the plurality of anodes is arranged to substantially face a cathode of the plurality of cathodes.

[0074] Embodiment 8. The system of any one of Embodiments 1-7, wherein the first array comprises a rectangular array.

[0075] Embodiment 9. The system of any one of Embodiments 1-8, wherein the second array comprises a rectangular array.

[0076] Embodiment 10. The system of any one of Embodiments 1-9, wherein the plurality of cathode electrical leads comprise a first plurality of electrical traces arranged to electrically couple a first plurality of rows of cathodes or a first plurality of columns of cathodes.

[0077] Embodiment 11. The system of any one of Embodiments 1-10, wherein the plurality of anode electrical leads comprise a second plurality of electrical traces arranged to electrically couple a second plurality of columns of anodes or a second plurality of rows of anodes.

[0078] Embodiment 12. The system of Embodiment 11, wherein the: controller comprises: (i) a first multiplexer configured to select a first row of the first plurality of rows or a first column of the first plurality of columns and (ii) a second multiplexer configured to select a second column of the second plurality of columns or a second row of the second plurality of rows.

[0079] Embodiment 13. The system of Embodiment 12, wherein the controller is configured to measure an impedance or conductance between a cathode-anode pair of the plurality of cathode-anode pairs that is located at a location defined by the first row and the second column or by the first column and the second row.

[0080] Embodiment 14. The system of any one of Embodiments 10-13, wherein the plurality of cathode electrical leads further comprise a third plurality of electrical traces arranged to electrically couple the first plurality of rows of cathodes or the first plurality of columns of cathodes.

[0081] Embodiment 15. The system of any one of Embodiments 11-14, wherein the plurality of anode electrical leads further comprise a fourth plurality of electrical traces arranged to electrically couple the second plurality of columns of anodes or the second plurality of rows of anodes.

[0082] Embodiment 16. The system of any one of Embodiments 11-15, wherein the plurality of cathodes or the plurality of anodes are formed from a first metallic layer located on the flexible substrate.

[0083] Embodiment 17. The system of Embodiment 16, further comprising an insulating layer located above the first metallic layer.

[0084] Embodiment 18. The system of Embodiment 17, wherein the insulating layer is selected from the group consisting of: crosslinked SU-8 photoresist, polyimide, silicone, polyethylene terephthalate (PET), poly dimethylsiloxane (PDMS), and any combination thereof. [0085] Embodiment 19. The system of Embodiment 17 or 18, wherein the plurality of cathodes or the plurality of anodes are formed from a second metallic layer located above the insulating layer.

[0086] Embodiment 20. The system of any one of Embodiments 16-19, wherein the plurality of cathode electrical leads or the plurality of anode electrical leads are formed from the first metallic layer.

[0087] Embodiment 21. The system of Embodiment 19 or 20, wherein the plurality' of cathode electrical leads or the plurality of anode electrical leads are formed from the second metallic layer.

[0088] Embodiment 22. The system of any one of Embodiments 19-21, further comprising a plurality of vias configured to electrically couple the plurality of cathode electrical leads from the first metallic layer to the second metallic layer or to electrically couple the plurality' of anode electrical leads from the first metallic layer to the second metallic layer.

[0089] Embodiment 23. The system of any one of Embodiments 1-9, wherein each cathode electrical lead of the plurality of cathode electrical leads is electrically coupled to a single cathode of the plurality of cathodes.

[0090] Embodiment 24. The system of any one of Embodiments 1-9 or of Embodiment 23, wherein each anode electrical lead of the plurality of anode electrical leads is electrically coupled to a single anode of the plurality of anodes.

[0091] Embodiment 25. The system of any one of Embodiments 1 -24, wherein the flexible substrate comprises a plurality' of cuts configured to allow the flexible substrate to further bend when adhered to a surface.

[0092] Embodiment 26. The system of Embodiment 25, wherein each cut of the plurality of cuts is located in proximity to a cathode of the plurality of cathodes or to an anode of the plurality of anodes.

[0093] Embodiment 27. The system of Embodiment 25 or 26, wherein each cut of the plurality of cuts substantially surrounds a cathode or the plurality of cathodes or an anode of the plurality of anodes.

[0094] Embodiment 28. The system of any one of Embodiments 25-27, wherein each cut of the plurality of cuts is located in proximity to a cathode electrical lead of the plurality of cathode electrical leads or to an anode electrical lead of the plurality of anode electrical leads. [0095] Embodiment 29. The system of any one of Embodiments 25-28, wherein each cut of the plurality of cuts substantially surrounds a cathode electrical lead of the plurality of cathode electrical leads or an anode electrical lead of the plurality of anode electrical leads. [0096] Embodiment 30. The system of any one of Embodiments 1-29, wherein each cathode-anode pair of the plurality of cathode-anode pairs comprises a cathode of the plurality of cathodes located at least 10 micrometers (pm) from an anode of the plurality of anodes.

[0097] Embodiment 31. The system of any one of Embodiments 1-30, wherein each cathode-anode pair of the plurality of cathode-anode pairs comprises a cathode of the plurality of cathodes located at most 100 pm from an anode of the plurality of anodes.

[0098] Embodiment 32. The system of any one of Embodiments 1-31, wherein each cathode-anode pair of the plurality of cathode-anode pairs is located at least 1 pm from all other cathode-anode pairs of the plurality of cathode-anode pairs.

[0099] Embodiment 33. The system of any one of Embodiments 1-32, wherein each cathode-anode pair of the plurality of cathode-anode pairs is located at most 10 millimeters (mm) from all other cathode-anode pairs of the plurality of cathode-anode pairs.

Claims

CLAIMS A system comprising: a flexible substrate; a plurality of cathodes arranged in a first array on the flexible substrate; a plurality' of anodes arranged in a second array on the flexible substrate, each anode of the plurality of anodes located in proximity to a cathode of the plurality of cathodes, thereby forming a plurality of cathode-anode pairs; a plurality' of cathode electrical leads electrically coupled to the plurality of cathodes; a plurality' of anode electrical leads electrically coupled to the plurality of anodes; and a controller electrically coupled to the plurality of cathode electrical leads and electrically coupled to the plurality of anode electrical leads and configured to measure a plurality of impedances or conductances, each impedance or conductance of the plurality of impedances or conductances corresponding to a cathode-anode pair of the plurality of cathode-anode pairs. The system of claim 1, wherein the flexible substrate is selected from the group consisting of: polyimide, silicone, polyethylene terephthalate (PET), poly dimethylsiloxane (PDMS), and any combination thereof. The system of claim 1, wherein each cathode of the plurality of cathodes has a circular, ellipsoidal, square, or rectangular shape. The system of claim 1, wherein each anode of the plurality of anodes has a circular, ellipsoidal, square, or rectangular shape. The system of claim 1, wherein each anode of the plurality of anodes substantially surrounds a cathode of the plurality of cathodes or wherein each cathode of the plurality of cathodes substantially surrounds an anode of the plurality of anodes. The system of claim 5, wherein each anode of the plurality of anodes entirely surrounds a cathode of the plurality of cathodes or wherein each cathode of the plurality of cathodes entirely surrounds an anode of the plurality of anodes. The system of claim 1, wherein each anode of the plurality of anodes is arranged to substantially face a cathode of the plurality of cathodes. The system of claim 1, wherein the first array comprises a rectangular array. The system of claim 1, wherein the second array comprises a rectangular array. The system of claim 1, wherein the plurality of cathode electrical leads comprise a first plurality of electrical traces arranged to electrically couple a first plurality of rows of cathodes or a first plurality of columns of cathodes. The system of claim 1, wherein the plurality of anode electrical leads comprise a second plurality of electrical traces arranged to electrically couple a second plurality of columns of anodes or a second plurality of rows of anodes. The system of claim 11, wherein the: controller comprises: (i) a first multiplexer configured to select a first row of the first plurality of rows or a first column of the first plurality of columns and (ii) a second multiplexer configured to select a second column of the second plurality of columns or a second row of the second plurality of rows. The system of claim 12, wherein the controller is configured to measure an impedance or conductance between a cathode-anode pair of the plurality of cathode-anode pairs that is located at a location defined by the first row and the second column or by the first column and the second row. The system of claim 10, wherein the plurality of cathode electrical leads further comprise a third plurality of electrical traces arranged to electrically couple the first plurality of rows of cathodes or the first plurality of columns of cathodes. The system of claim 11, wherein the plurality of anode electrical leads further comprise a fourth plurality of electrical traces arranged to electrically couple the second plurality of columns of anodes or the second plurality of rows of anodes. The system of claim 11, wherein the plurality of cathodes or the plurality of anodes are formed from a first metallic layer located on the flexible substrate. The system of claim 16, further comprising an insulating layer located above the first metallic layer. The system of claim 17, wherein the insulating layer is selected from the group consisting of: crosslinked SU-8 photoresist, polyimide, silicone, polyethylene terephthalate (PET), poly dimethylsiloxane (PDMS), and any combination thereof. The system of claim 17, wherein the plurality of cathodes or the plurality of anodes are formed from a second metallic layer located above the insulating layer. The system of claim 16, wherein the plurality of cathode electrical leads or the plurality of anode electrical leads are formed from the first metallic layer. The system of claim 19, wherein the plurality of cathode electrical leads or the plurality of anode electrical leads are formed from the second metallic layer. The system of claim 19, further comprising a plurality of vias configured to electrically couple the plurality of cathode electrical leads from the first metallic layer to the second metallic layer or to electrically couple the plurality of anode electrical leads from the first metallic layer to the second metallic layer. The system of claim 1, wherein each cathode electrical lead of the plurality of cathode electrical leads is electrically coupled to a single cathode of the plurality of cathodes. The system of claim 1, wherein each anode electrical lead of the plurality of anode electrical leads is electrically coupled to a single anode of the plurality of anodes. The system of claim 1, wherein the flexible substrate comprises a plurality of cuts configured to allow the flexible substrate to further bend when adhered to a surface. The system of claim 25, wherein each cut of the plurality of cuts is located in proximity to a cathode of the plurality of cathodes or to an anode of the plurality of anodes. The system of claim 25, wherein each cut of the plurality of cuts substantially surrounds a cathode or the plurality of cathodes or an anode of the plurality of anodes. The system of claim 25, wherein each cut of the plurality of cuts is located in proximity to a cathode electrical lead of the plurality' of cathode electrical leads or to an anode electrical lead of the plurality' of anode electrical leads. The system of claim 25, wherein each cut of the plurality of cuts substantially surrounds a cathode electrical lead of the plurality of cathode electrical leads or an anode electrical lead of the plurality of anode electrical leads. The system of claim 1, wherein each cathode-anode pair of the plurality' of cathodeanode pairs comprises a cathode of the plurality of cathodes located at least 10 micrometers (pm) from an anode of the plurality of anodes. The system of claim 1, wherein each cathode-anode pair of the plurality' of cathodeanode pairs comprises a cathode of the plurality of cathodes located at most 100 pm from an anode of the plurality of anodes. The system of claim 1, wherein each cathode-anode pair of the plurality' of cathodeanode pairs is located at least 1 pm from all other cathode-anode pairs of the plurality' of cathode-anode pairs The system of claim 1, wherein each cathode-anode pair of the plurality' of cathodeanode pairs is located at most 10 millimeters (mm) from all other cathode-anode pairs of the plurality of cathode-anode pairs.