Bidirectional textile electrodes and methods of producing same

Abstract

Bidirectional textile electrodes and methods of producing same. A textile device may include a base layer; a spacer-layer coupled to the base layer configured to provide a raised textile profile relative to the base layer; and a user-facing layer coupled to the spacer-layer constructed of a knitted combination of non-conductive fibers and stainless-steel microwires for interfacing with user skin, the stainless-steel microwires electrically coupled to a computing device.

Description

BIDIRECTIONAL TEXTILE ELECTRODES AND METHODS OF PRODUCING SAMECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. provisional patent application number 63 / 572,587, entitled “BIDIRECTIONAL TEXTILE ELECTRODES AND METHODS OF PRODUCING SAME”, filed on April 1 , 2024, the entire contents of which are hereby incorporated by reference herein.FIELD

[0002] Embodiments of the present disclosure generally relate to the field of textile computing systems and, in particular to textile electrodes.BACKGROUND

[0003] Textile computing systems may include textile bodies having one or a combination of non-conductive yarns and integrated conductive yarns providing circuit structures. Circuit structures may be configured as sensors or actuators for acquiring bio-signal data associated with a user or for providing actuating signals providing feedback to a user.SUMMARY

[0004] Textile computing platforms may include electrodes for interfacing with a user’s skin. In some examples, electrodes may include hydrogel electrodes for providing electrical signals providing neurostimulation signals to a user. In some scenarios, hydrogel electrodes may be prone to drying out over time, may irritate a user’s skin with prolonged use, and may be generally configured for single use.

[0005] The present disclosure describes embodiments of textile electrodes configured such that an electrode-to-skin impedance is adept for transmitting electrical signals for providing neurostimulation to a user. Embodiments of textile electrodes may include a water-based skin preparation solution at a user-facing layer for interfacing with a user’s skin. Embodiments of textile electrodes may be reusable and may maintain desirable electro-mechanical properties following a plurality of laundering cycles. Features of embodiments of such textile electrodes will be described in the present disclosure.

[0006] In one aspect, the present disclosure describes a textile device comprising: a base layer; a spacer-layer coupled to the base layer configured to provide a raised textile profile relative to the base layer; and a user-facing layer coupled to the spacer-layer constructed of a knitted combination of non-conductive fibers and stainless-steel wires for interfacing with user skin, the stainless-steel wires electrically coupled to a computing device.

[0007] In some embodiments, the knitted combination of non-conductive fibers and stainless- steel wires includes polyester yarn and stainless-steel microwires.

[0008] In some embodiments, the stainless-steel wires have a diameter of approximately 0.03 millimeters.

[0009] In some embodiments, a composition of the knitted combination includes approximately 70% to 80% polyester yarn.

[0010] In some embodiments, the composition of the knitted combination includes approximately 71% polyester yarn and 29% stainless-steel wires.

[0011] In some embodiments, the stainless-steel wires are coated with a biocompatible polymer: polyelectrolyte complex poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ink.

[0012] In some embodiments, the stainless-steel wires are coated with the PEDOT:PSS ink at a coating rate of 150 pL / min, with a curing temperature of approximately 190°C, and a coating speed of 20 RPM, based on a roll-to-roll coating system.

[0013] In some embodiments, the textile device includes a water-based preparation solution configured to be applied to the user-facing layer for reducing skin to textile impedance.

[0014] In some embodiments, the knitted combination is based on a stitch density in the range of 80 to 150 courses per centimeter (cpc) x wales per centimeter (wpc).

[0015] In some embodiments, the knitted combination is based on stitch lengths in the range of 1.8 millimeters to 6.4 millimeters.

[0016] In some embodiments, the knitted combination includes a symmetric knit pattern in at least one of a horizontal direction or a vertical direction.

[0017] In some embodiments, the knitted combination includes a tight knit loops with minimal gaps among the series of tight knit loops.

[0018] In some embodiments, the spacer-layer includes a knitted non-conductive polyester yarn.

[0019] In some embodiments, the base layer includes a nylon yarn interlaced with a textile body, wherein the textile body is constructed of a double jersey structure including nylon / spandex yarns.

[0020] In some embodiments, the computing device includes: a processor; and a memory storing processor-executable instructions that, when executed, configure the processor to: detect one or more signals based on electrical signals conducted by the stainless-steel microwires; and generate one or more data signals representing physiological data based on a skin-to-textile interface at the user skin.

[0021] In some embodiments, the computing device includes a processor; and a memory storing processor-executable instructions that, when executed, configure the processor to: generate an electrical signal representing a neurostimulation signal; and transmit the electrical signal representing the neurostimulation signal across to the coupled stainless-steel wires for providing a neurostimulation signal at the skin-to-textile interface.

[0022] In this respect, before explaining at least one embodiment in detail, it is to be understood that the embodiments are not limited in application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

[0023] Many further features and combinations thereof concerning embodiments described herein will appear to those skilled in the art following a reading of the present disclosure.DESCRIPTION OF THE FIGURES

[0024] In the figures, embodiments are illustrated by way of example. It is to be expressly understood that the description and figures are only for the purpose of illustration and as an aid to understanding.

[0025] Embodiments will now be described, by way of example only, with reference to the attached figures, wherein in the figures:

[0026] FIG. 1 illustrates a plurality of neurostimulation garments donned by a user, in accordance with embodiments of the present disclosure;

[0027] FIG. 2 illustrates microscopic images of yarns and knit patterns for configuring textile neurostimulation electrodes, in accordance with embodiments of the present disclosure;

[0028] FIG. 3 illustrates enlarged side views of textile electrodes, in accordance with embodiments of the present disclosure;

[0029] FIG. 4 illustrates a cross-sectional perspective view of a textile electrode, in accordance with embodiments of the present disclosure;

[0030] FIG. 5 illustrates microscopic images of a three-dimensional knit structure of a userfacing layer, in accordance with embodiments of the present disclosure;

[0031] FIG. 6 illustrates an enlarged plan view of a user-facing layer of a textile electrode, in accordance with embodiments of the present disclosure;

[0032] FIG. 7 illustrates an enlarged plan view of a user-facing layer of a textile electrode, in accordance with embodiments of the present disclosure;

[0033] FIG. 8 illustrates an enlarged plan view of a user-facing layer of a textile electrode, in accordance with embodiments of the present disclosure;

[0034] FIG. 9 illustrates electrocardiogram data charts showing ECG data generated by electrodes, in accordance with embodiments of the present disclosure;

[0035] FIG. 10 illustrates a chart showing impedance amplitude against a spectrum of frequencies for various electrodes, in accordance with embodiments of the present disclosure;

[0036] FIG. 11 illustrates a chart with characterization data showing impedance amplitude across a range of frequencies when an array of water-based lotions is used, in accordance with embodiments of the present disclosure;

[0037] FIG. 12 illustrates a chart with characterization data showing impedance amplitude across a range of frequencies for a series of embodiments of textile electrodes, in accordance with embodiments of the present disclosure;

[0038] FIG. 13 illustrates a chart showing average impedance values at 5,000 Hz for a plurality of textile electrode configurations, in accordance with embodiments of the present disclosure;

[0039] FIG. 14 illustrates a recruitment curve of a stimulation response for a wrist flexion motion, in accordance with embodiments of the present disclosure;

[0040] FIG. 15 illustrates a kinematic recruitment curve across various subjects, in accordance with embodiments of the present disclosure;

[0041] FIG. 16 illustrates charts showing metrics and survey results of evoked sensory responses, in accordance with embodiments of the present disclosure;

[0042] FIG. 17 illustrates charts showing user-skin to textile impedance measurements, in accordance with embodiments of the present disclosure;

[0043] FIGS. 18 and 19 illustrate charts showing kinematic recruitment curves, in accordance with embodiments of the present disclosure;

[0044] FIG. 20 illustrate charts showing average skin-electrode impedance results of stainless- steel textile electrodes and PEDOT:PSS coated stainless-steel electrodes, in accordance with embodiments of the present disclosure;

[0045] FIG. 21 illustrates charts showing recruitment curves of wrist flexion, in accordance with embodiments of the present disclosure;

[0046] FIG. 22 illustrates a chart showing a voltage transient response of subjects at 7mA, in accordance with embodiments of the present disclosure;

[0047] FIG. 23 illustrates a chart showing Fourier transform infrared spectroscopy-attenuated total reflectance spectra for uncoated and coated stainless steel yarns, in accordance with embodiments of the present disclosure;

[0048] FIG. 24 illustrates a chart showing water permeability data of textile electrodes, in accordance with embodiments of the present disclosure;

[0049] FIG. 25 illustrates a chart showing stress-strain curves of embodiments of textile electrodes, in accordance with embodiments of the present disclosure;

[0050] FIG. 26 illustrates a chart showing a fatigue response of textile electrodes, in accordance with embodiments of the present disclosure; and

[0051] FIG. 27 illustrates a chart showing skin-electrode impedance measurements, in accordance with embodiments of the present disclosure.DETAILED DESCRIPTION

[0052] The present disclosure provides embodiments of textile electrodes configured such that an electrode-to-skin impedance is adept for transmitting electrical signals for providing neurostimulation to a user. Embodiments of textile electrodes may include a water-based skin preparation solution at a user-facing layer for interfacing with a user’s skin. Embodiments of textile electrodes may be reusable and may maintain desirable electro-mechanical properties following a plurality of laundering cycles. Features of embodiments of such textile electrodes will be described in the present disclosure.

[0053] In some embodiments, textiles including conductive yarns integrated therein may be configured as textile garments having electrically conductive circuits, sensor devices, actuator devices, or other types of data acquisition or feedback components. Textile garments may include shirts, pants, undergarments, chest bands, among other garments that may be donned by a user.

[0054] In some embodiments, electrically conductive paths or structures may be integrated into textiles by one or a combination of methods including inlaying, knitting, weaving, embroidery, adhesive bonding, or mechanical bonding. Other methods of integrating conductive paths into textile structures may be used.

[0055] In some examples, electrical, mechanical, or electro-mechanical fibers, such as piezoelectric, electromagnetic, shape shifting, or other types of yarns may be knitted or weavedinto a textile fabric. For instance, electro-mechanical yarn may be knitted or weaved in a “zig-zag” pattern across textile fabric to provide sensor or actuator structures.

[0056] In some embodiments, a textile body may include a plurality of conductive fibers interlaced with a plurality of non-conductive fibers. The conductive fibers may define a plurality of signal paths suitable for delivering data or power to form a conductive fiber network. In some embodiments, the textile body may be formed of other textile forms or techniques such as weaving, knitting (warp, weft, etc.), among examples. In some embodiments, textile body may include any one of a knitted textile, a woven textile, a cut and sewn textile, a knitted fabric, a nonknitted fabric, in a combination or permutation thereof.

[0057] In some embodiments, interlaced fibers may include fibers crossing over and / or under one another in a predetermined configuration, such as alternately over and under one another in textile a layer. When interlaced, adjacent fibers may contact each other at engagement or intersection points (e.g. points where one fiber crosses over or under another fiber). In some examples, first fibers extending in a first direction can be interlaced with second fibers extending laterally or transverse to the fibers extending in the first direction. Interlaced fibers extending in a textile body may be referred to as a network of fibers.

[0058] As used to describe some embodiments herein, “integrated” or “integrally” may refer to combining, coordinating, or otherwise bringing together separate elements so as to provide a harmonious, consistent, interrelated whole. In embodiments of textiles, a textile may include various sections comprising networks of fibers with varying structural properties. In some examples, a textile body may have a section comprising a network of conductive fibers and a section comprising a network of non-conductive fibers. Two or more sections comprising networks of fibers may be “integrated” together into a textile (or “integrally formed”) when at least one fiber of one network is interlaced with at least one fiber of the other network such that the two networks form a layer of the textile. In some examples, when integrated, two sections of a textile may also be described as being substantially inseparable from the textile. Here, “substantially inseparable” refers to the notion that separation of the sections of the textile body from each other results in disassembly or destruction of the textile body itself.

[0059] In some examples, conductive fabric (e.g. group of conductive fibers) can be knit along with (e.g. to be integral with) the base fabric (e.g. surface) in a layer. Such knitting may be performed using a circular knit machine or a flatbed knit machine, warp knit, or the like, from a vendor such as Santoni, Stoll, or Karl Mayer.

[0060] In some description herein of embodiments, the terms fiber or yarn may be used interchangeably.

[0061] Neurostimulation may include operations of activating or modulating the activity of nerves or muscles based on electrical currents delivered through electrode interfaces [1], Depending on the site of delivery and stimulation pulse parameters, activated networks and ultimately evoked stimulation responses may vary. Neurostimulation applications range from rehabilitation, pain relief, or muscle strengthening to restoration of lost functions such as movement or sensation for individuals with neuromuscular deficits [2-9],

[0062] In some embodiments, neurostimulation systems may include an electrical pulse generator, one or more pairs of stimulation electrodes configured to deliver pulses to the target location on or inside the user body, and lead wires coupling the stimulator to the electrodes. In some scenarios, requirements in developing safe and effective stimulation electrodes include electrodes that: i) have sufficiently low electrode-skin impedance to deliver functional intensities of neurostimulation in a safe and comfortable manner; ii) have an interface with the skin providing consistent functionality throughout the neurostimulation treatment / usage session; iii) if reusable, should maintain consistent stimulation performance through wash or cleaning and disinfection processes; iv) where prolonged repeated use is of interest, should be breathable, biocompatible, and hypoallergenic [13,14],

[0063] Example stimulation electrodes may include hydrogel electrodes. Embodiments of hydrogel electrodes may provide comfortable electrical stimulation to a user; however, some example hydrogel electrodes may be limited by their applicability for interventions requiring longterm frequent day-to-day usage. It may be desirable to provide fully textile electrodes constructed based on scalable programmable machine knitting techniques to provide a washable, reusable, flexible, and breathable neurostimulation interface with embedded interconnects.

[0064] In some examples of electrodes for stimulating user nerves or muscles, adhesive hydrogel electrodes may be configured to provide low electrode-skin impedance, optimal adhesion to the user skin, and reliable contact with the user skin.

[0010] In some scenarios, hydrogel electrodes may dry out over time, and may promulgate user skin irritations or allergic reactions with prolonged use. In some examples, hydrogel electrodes may be intended for single use and may be intended to be disposable.

[0010] Such characteristics of hydrogel electrodes may impede prolonged or repeated use for neurostimulation, such as for functional electrical stimulation for movement rehabilitation and for treatment of chronic user pain [2, 11 , 12], It may be desirable to provide textile electrodes configured to be breathable, flexible, and reusable neurostimulation interfaces

[0010] , whilst providing similar performance characteristics of hydrogel electrodes.

[0065] Table 1 outlines examples of textile-based stimulation electrodes and associated observations from testing of the respective textile-based stimulation electrodes. As will be described, such example textile-based stimulation electrodes may not yet provide effective devices with comparable on-body functionality and durability as hydrogel electrode devices. As will be described in the present disclosure, it may be desirable to provide breathable and reusable stimulation electrodes that may be applied to a user for long durations of time.

[0066] In some examples, electrodes may be produced based on a variety of methods including printing, embroidery, and knitting. [10, 11 , 14, 15] In some scenarios, printed textile stimulation electrodes may have poor breathability and functional features may degrade with repeated laundering. [16, 17]

[0067] In some scenarios, examples of knitted stimulation electrodes or embroidery stimulation electrodes may not be usable in dry conditions and may require wetting or additional adhesive gel pads developed so far were not usable in dry condition and required wetting or use of additional adhesive gel pads for providing a user with comfortable neurostimulation [10, 12, 18 to 20],

[0068] In some scenarios, examples of embroidered stimulation electrodes were not tested for functional performance and showed poor durability following laundering cycles. [11 , 20, 21] In some examples of textile electrodes listed in Table 1 , the electrodes may be constructed of silverbased conductive materials [21 to 23], Silver yarns may show degradation of physical propertiesfollowing laundering and have been observed to have increased resistance of up to 300% following 50 laundering cycles due in part to increased silver sulfidation and mechanical stress during laundering cycles [24, 25], It may be desirable to provide textile electrode fabrication techniques and textile fabric options that may provide dry textile stimulation electrodes having desirable functional specifications while retaining such functional specifications following numerous uses and laundering cycles.

[0069] In some scenarios, textile stimulation electrodes may be unsuitable for neurostimulation applications in a dry state when a high skin-electrode impedance is observed. [1 , 11 , 19] In some examples, attempts to reduce skin-electrode impedance values included attempts to wet such textile electrodes or attempts to attach hydrogel pads to textile electrodes. [1 ,11 ,22] While wetting textile electrodes may assist with reducing skin-electrode impedance values, neurostimulation performance capabilities become variable or unstable as the textile electrode may dry out, which may occur in as little as 18 minutes [2, 10, 19, 22]

[0070] In some scenarios, attaching hydrogel to the surface of textile electrodes, while effective, provides for undesirable features observed with gel electrodes including lack of breathability, increased occurrences of skin irritation, and a requirement for disposing of gel pads as single-use devices [14, 26]TABLE 1 : Example Textile-Based Stimulation Electrodes Based on Various Material Compositions* Where ROM = Range of Motion, NR = Not Reported

[0071] The present disclosure provides embodiments of textile electrodes that may be configured for providing neurostimulation to textile garment users. As will be disclosed, someembodiments of textile electrodes may be constructed based on three-dimensional knit operations and may include stainless steel microwire components.

[0072] In some embodiments, textile electrodes configured for neurostimulation may be used in combination with a skin preparation compound including water-based skin lotions. A combination of textile electrode features in combination with water-based skin lotion preparations may be configured to provide a suitably breathable, washable, reusable, and functional alternative to gel electrodes that may be used for appreciably greater durations of time. Some embodiments may be constructed based on scalable programmable machine knitting techniques and combined with water-based skin preparation compounds to provide a user with a comfortable, washable, reusable, flexible, and breathable neurostimulation interface for neurostimulation system applications.

[0073] Reference is made to FIG. 1 , which illustrates a plurality of neurostimulation garments donned by a user, in accordance with embodiments of the present disclosure. A neurostimulation garment may be a textile band that may be worn as a leg band 102, a torso band 104, an upperarm band 106, or a forearm band 108.

[0074] A neurostimulation garment may be a forearm band 108, and may include a textile band and one or more textile electrodes integrated in the textile band. The neurostimulation garment may include a combination of non-conductive yarns or fibers and conductive yarns or fibers. The conductive yarns or fibers may be configured to provide textile electrodes to form sensor devices or actuation devices. Conductive yarns may be interlaced within the textile band for electrically coupling one or more electrodes among a plurality of electrodes.

[0075] In some embodiments, neurostimulation garments may be configured for providing neurostimulation for providing a user with pain relief. Such neurostimulation applications may be known as transcutaneous electrical stimulation (TENS).

[0076] In some embodiments, neurostimulation garments may be configured for providing induction of motor responses, such as functional electrical stimulation for therapeutic or restorative purposes.

[0077] In some embodiments, neurostimulation garments may be configured for induction of sensory responses, such as its utility in creating a sensory proxy for one or more artificial limbs used by individuals with one or more prior amputated limbs.

[0078] In some embodiments, textile electrodes for neurostimulation applications may be configured with textile surface geometries for reducing impedance between the textile electrode and a skin surface of a user. In some embodiments, textile electrodes may be configured with varying textile materials and knit patterns optimized for delivering neurostimulation based on prescribed specifications.

[0079] Reference is made to FIG. 2, which illustrates microscopic images of yarns and knit patterns for configuring textile neurostimulation electrodes, in accordance with embodiments of the present disclosure.

[0080] In some embodiments, textile electrodes may be knitted by a flat-bed knitting apparatus. FIG. 2 shows a microscopic image 210 illustrating an enlarged portion of a textile electrode layer constructed from microwire yarn. In another example, FIG. 2 shows a microscopic image 220 illustrating an enlarged portion of a textile electrode layer constructed from silver-plated nylon yarn. In some embodiments, textile electrodes may be knit from conductive material including silver-plated polyamides to hybrid structures of microwire yarns.

[0081] In some embodiments, flat conductive surfaces having varying sizes and shapes may be incorporated into knitted substrates by knitting apparatus. In some scenarios, flat knitted electrode devices may be geometrically configured to adaptively interface with contours of a user’s skin.

[0082] As an example, reference is made to FIG. 3, which illustrates enlarged side views of textile electrodes, in accordance with embodiments of the present disclosure. FIG. 3 shows an enlarged side view of a flat textile electrode 310 including a user-facing surface constructed of conductive material and a substrate layer constructed of passive material.

[0083] Further, FIG. 3 shows an enlarged side view of a knitted 3D raised textile electrode 320. In some embodiments, knitting apparatus may be configured to construct varying textile electrode surface textures or textile electrode thicknesses.

[0084] In some embodiments, the illustrated knitted 3D raised textile electrode 320 may include a user-facing layer constructed of conductive material for providing electrical-based stimulation to a user. The illustrated 3D raised textile electrode 320 may include an intermediary layer constructed of passive or non-conductive material configured to provide structure. The illustrated 3D raised textile electrode 320 may further include a base layer that may be interlaced with a passive textile substrate of a garment. In some embodiments, the user-facing layer may be configured with preidentified surface coarseness, uniformity, or surface impedance properties based on configurable knitting parameters of knitting apparatus.

[0085]

[0086] Reference is made to FIG. 4, which illustrates a cross-sectional perspective view of a textile electrode 400, in accordance with embodiments of the present disclosure. The textile electrode 400 may include a plurality of layers including a user-facing layer 410, a spacer layer 420, and a base layer 430.

[0087] As will be described in the present disclosure, embodiments of a textile device may include a base layer 430, a spacer layer 420 coupled to the base layer 430, and a user facinglayer 410 coupled to the spacer layer 420. The spacer layer 420 may be configured to provide a raised textile profile relative to the base layer 430.

[0088] In some embodiments, the user-facing layer 410 may be constructed of a knitted combination of non-conductive fibers and stainless-steel wires for interfacing with the user skin. The stainless-steel wires may be electrically coupled to a computing device.

[0089] In some embodiments, the computing device (not explicitly illustrated in FIG. 4) may include a processor and a memory storing processor-executable instructions that, when executed, configure the processor to detect one or more signals based on electrical signals conducted by the stainless-steel microwires and generate one or more data signals representing physiological data based on a skin-to-textile interface at the user skin. In the present example, the textile electrode device may be configured as a data acquisition device for generating signals representing physiological data associated with a user.

[0090] In some embodiments, the processor may generate an electrical signal representing a neurostimulation signal and transmit the electrical signal across the coupled stainless-steel wires for providing a neurostimulation signal at the skin-to-textile interface. In the present example, the textile electrode device may be configured as a data actuation device, such as for imparting neurostimulation signals to a user at the skin-to-textile interface.

[0091] The textile electrode 400 may be integrated or otherwise interlaced with a textile body (not explicitly illustrated in FIG. 4), such as a textile garment. For example, the textile electrode 400 may be integrated in a textile band to be donned by a user around a user waist. In some examples, the textile electrode 400 may be integrated in a shirt to be worn by a user. In some examples, the textile electrode 400 may be integrated in an arm band to be worn by a user on the user’s forearm.

[0092] In some embodiments, the user-facing layer 410 may be configured to contact a target area of a user’s skin. For example, a forearm band 108 (FIG. 1) configured to be donned by a user on the forearm may include one or more textile electrodes 400 for providing functional electrical stimulation to a user’s arm or hand. The forearm band 108 may be configured to be donned by a user such that one or more textile electrodes 400 be positioned proximal to target nerve or tendon for electrical stimulation.

[0093] In some embodiments, the user-facing layer 410 may be fabricated based on a V-bed flat knitting machine (e.g., by Stoll, Ruetlingen, Germany). Other types of knitting apparatus may be configured for fabricating the user-facing layer 410.

[0094] In some embodiments, the user-facing layer 410 may include a combination of stainless steel microwires and polyester. In some embodiments, the user-facing layer 410 may be a knitted combination of non-conductive fibers and stainless-steel wires including polyester yarn and stainless-steel microwires.

[0095] In some embodiments, the combination of stainless steel microwires and polyester includes a greater percentage of polyester than stainless steel microwires. In some embodiments, the polyester may comprise 70% to 80% of the textile material and the stainless steel microwires may comprise the remaining percentage of textile material.

[0096] In some embodiments, the combination may include approximately 70% polyester and 30% stainless steel microwires. A prototype embodiment included a combination of stainless steel microwires and polyester according to a 71% polyester to 29% stainless steel ratio. In some embodiments, the stainless-steel wire or yarn diameter may be approximately 0.03 mm.

[0097] In some embodiments, the user-facing layer 410 may include stainless-steel wires or yarns coated with a biocompatible polymer: polyelectrolyte complex poly(3,4- ethylenedioxythiophene:poly(styrene sulfonate) (PEDOT:PSS) ink.

[0098] In some embodiments, the stainless-steel wires may have been coated with the PEDOT:PSS ink at a coating rate of 150 pL / min, with a curing temperature of approximately 190°C, and a coating speed of 20 RPM, based on a roll-to-roll coating system (Aumann Espelkamp, DLH 170, Germany). For example, PEDOT:PSS may be an intrinsically conductive polymer (ICP) to form composites with high electrochemical properties.

[0099] In some embodiments, to configure desirable user-skin to textile electrode contact, the user-facing layer 410 may be configured with a three-dimensional knit structure having one or more knit patterns. Examples of such knit structure patterns will be illustrated in the present disclosure. In some embodiments, the user-facing layer 410 may include a pristine / coated yarn.

[0100] The spacer layer 420 may include a knitted structure coupled to the user-facing layer 410. In some embodiments, the spacer layer 420 may be constructed of a knitted non-conductive polyester yarn material.

[0101] The base layer 430 may include a knitted structure coupled to the spacer layer 420. In some embodiments, the base layer 430 may be constructed of a nylon yarn material. In some embodiments, the base layer may be interlaced with a textile body, where the textile body may be constructed of a double jersey structure including nylon / spandex yarns.

[0102] In some embodiments, the textile electrode 400 may be interlaced or integrated in a textile body. For example, the textile body may include a top layer and a bottom layer having a double jersey structure including a nylon I spandex composition. Other compositions may be used.

[0103] Depending on the target application of textile electrodes for providing neurostimulation signals, textile electrodes may be knitted in a variety of different shapes or sizes. For example, textile electrode shapes may include squares, rectangles, ovals, or circles. In some examples, textile electrodes may have varying sizes depending on the target surface area of user muscle or nerve portion to be stimulated. For example, textile electrode may have a planar dimension of 5 cm x 5 cm, 10 cm x 7.5 cm, 4.5 cm x 4 cm, or another dimension.

[0104] In some embodiments, the textile device may include usage with a combination of a water-based preparation solution configured to be applied to the user-facing layer 410 for reducing skin-to-textile impedance.

[0105] FIG. 5 illustrates microscopic images 500 of a three-dimensional knit structure of a userfacing layer 410 (FIG. 4), in accordance with embodiments of textile electrodes of the present disclosure.

[0106] FIG. 5(a) illustrates a microscopic image at 60x magnification of a user-facing layer 410 having stainless steel microwires integrated in the yarn. FIG. 5(b) illustrates a microscopic image at 250x magnification of the user-facing layer 410 having stainless steel microwires integrated in the yarn.

[0107] In another embodiment, FIG. 5(c) illustrates a microscopic image at 60x magnficiation of the user-facing layer 410 having PEDOT:PSS coated stainless steel microwires integrated in the yarn. FIG. 5(d) illustrates a microscopic image at 250x magnification of the user-facing layer 410 having PEDOT:PSS coated stainless steel microwires integrated in the yarn.

[0108] As described, the user-facing layer 410 may be constructed by knitting with varying stitch densities or combinations of conductive yarns. In some embodiments, the spacer layer 420 may be knitted with similar combinations of conductive yarns as in the user-facing layer 410 for altering electrically conductive properties of the overall user-facing layer 410. The surface layer of the conductive user-facing layer 410 may include various configurations of yarn stitch density, loop length, or loop arrangement for desirable morphology.

[0109] FIG. 6 illustrates an enlarged plan view of a user-facing layer 600 of a textile electrode, in accordance with embodiments of the present disclosure. The user-facing layer 600 may include loops having a symmetric structure in a horizontal or vertical direction.

[0110] FIG. 7 illustrates an enlarged plan view of a user-facing layer 700 of a textile electrode, in accordance with embodiments of the present disclosure. The user-facing layer 700 may include loops that may overlap with adjacent loops and may be configured such that the adjacent loops have an irregular pattern extending across the user-facing layer 700.

[0111] FIG. 8 illustrates an enlarged plan view of a user-facing layer 800 of a textile electrode, in accordance with embodiments of the present disclosure. The user-facing layer 800 may include tightly knitted loops adjacent other tightly knitted loops in a substantially symmetrical orientation across the user-facing layer 800. In some scenarios, stitch density and tightness of knitted loops may be a function of variability of wale spacing and course spacing. In some scenarios, tightness of knitted loops may be a function of stitch length. Shorter stitch lengths (e.g., more stitches per inch I cm) may provide tighter, denser fabric. Longer stitch lengths may provide looser, more drapey fabric. In some scenarios, tightness of knitted loops may be a function of yarn tension. In some scenarios, tightness of knitted loops may be a function of needle size. Utilizing a larger needle may provide looser stiches. Utilizing a smaller needle may provide tighter stitches.

[0112] Textile electrodes may be configured as data acquisition devices, such as sensor devices for detecting and generating physiological data or bio-signal data associated with a garment user. In some scenarios, it may be desirable to configure textile electrodes as bidirectional devices capable of both: (i) a data acquisition device; and (ii) an output device, such as for providing neurostimulation to the garment user. As an example, textile electrodes for providing neurostimulation are configured with features for reducing the user-skin to textile electrode impedance, as compared to the user-skin to textile electrode impedance of textile electrodes configured primarily as data acquisition devices.

[0113] In some examples, textile electrodes configured as bi-directional devices may be as suitable for generating bio-signal data of a user as compared to a textile electrode configured as a unidirectional device. For example, a unidirectional device may be a gel electrode device configured to generating electrocardiogram data of a user. A bi-directional device may be one ormore embodiments of textile electrodes of the present disclosure that may be configurable to generate electrocardiogram data of a user and also to provide neurostimulation to the user.

[0114] To illustrate, FIG. 9 illustrates electrocardiogram (ECG) data charts showing ECG data generated by electrodes, in accordance with embodiments of the present disclosure. For example, a first ECG data chart 910 illustrates example ECG data generated by a gel electrode device. A second ECG data chart 920 illustrates example ECG data generated by an embodiment of a stainless-steel textile electrode described herein. In comparing the ECG data charts, the embodiment of the stainless-steel textile electrode may generate ECG data as well as when using example gel electrode devices. Gel electrode devices are known to be the industry benchmark for generating ECG data sets of a user.

[0115] Embodiments of the textile electrodes described herein may be configured with textile features for reducing the user skin to textile electrode impedance. Such features may include: (a) various choices for yarn materials associated with predetermined physical or electrical properties; (b) knit structure I patterns; (c) stitch length associated with construction of the textile electrode; or (d) stitch density associated with construction of the textile electrode. Embodiments of textile electrodes described herein may be optimized for the above-mentioned parameters to obtain a suitably reduced user skin to textile impedance, while providing desired functionality as a neurostimulation device.

[0116] In some embodiments, reducing user skin to textile electrode impedance may be provided based on one or more of: lower electrical resistance of yarns and suitability of yarns for knitting; altering the contact pressure provided by knitted fabrics, including flexibility of knitted fabrics and breathability of knitted fabrics; or identified stitch length and stitch density for conductive yarns for knitted electrodes.

[0117] In some embodiments, textile devices may be configured with optimized parameters based on a combination of stitch length, z-axis thickness, stitch density, yarn diameter, areal density, and yarn material and electrical properties. In some scenarios, stich length, yarn diameter, and yarn type may be correlated with improved skin electrode impedance. In some other scenarios, improved skin electrode impedance may additionally be correlated with stitchdensity and z-axis thickness. Accordingly, textile devices may be manufactured based on one or more tuned parameters to achieve a desirable skin electrode impedance.

[0118] For example, yarn material and structure may be chosen to reduce or minimize userskin to electrode impedance, while maintaining robustness against degradation as a result of laundering cycles.

[0119] Further, yarn knit structures of textiles, which may be characterized by stitch lengths (e.g., 1.8 to 6.4 mm) or stitch densities (e.g., ranging from 80 to 150 CPCxWPC) of textiles, may assist with maximizing user-skin contact with the textile electrode, thereby promoting localized pressure at the contact point between the user-skin and the textile electrode while keeping the textile electrode breathable, flexible, or stretchable from the user experience perspective.

[0120] Accordingly, in some embodiments, a user-facing layer 410 (FIG. 4) may be constructed of a knitted combination based on a stitch density in the range of 80 to 150 courses per centimeter (cpc) x wales per centimeter (wpc).

[0121] In some embodiments, the user-facing layer 410 (FIG. 4) may be constructed of a knitted combination based on stitch lengths in the range of 1.8 millimeters to 5.4 millimeters.

[0122] In some embodiments, the user-facing layer 410 (FIG. 4) may be constructed of a knitted combination including a symmetric knit pattern in at least one of a horizontal direction or a vertical direction.

[0123] In some embodiments, the user-facing layer 410 (FIG. 4) may be constructed of a knitted combination including tight knit loops with minimal gaps among the series of tight knit loops.

[0124] When comparing functional characteristics of textile electrodes configured for neurostimulation (e.g., bi-directional textile electrodes) and textile electrodes configured primarily for data acquisition (e.g., uni-directional textile electrodes), it may be desirable to characterize the electrical characteristics that are correlated to resulting user-skin to textile impedance.

[0125] Reference is made to FIG. 10, which illustrates a chart 1000 showing impedance amplitude against a spectrum of frequencies for various electrodes.

[0126] In some embodiments, textile electrodes may be configured as carbon electrodes including carbon yarns for generating bio-signal data of a user. Carbon electrodes may be examples of unidirectional textile electrodes. In some embodiments, textile electrodes may be configured as stainless steel electrodes, which in some embodiments may be coated with PEDOT:PSS ink.

[0127] For ensuring safe use by a textile electrode user, generated electrical current amplitude and pulse width of signals may need to be within a prescribed threshold. In some embodiments, determining safe usage by the textile electrode user may be based on empirical data, including factors or parameters including a just noticeable difference (JND) observation, user comfort questionnaire, or a pain threshold observation, among other factors, for determining whether functional levels of stimulations are provided to the user without causing undesirable discomfort.

[0128] Textile electrodes having greater user-skin to electrode impedance values may require that textile computing systems provide electrical signals with greater current than may be safe for a garment user for delivering neurostimulation signals. Accordingly, some embodiments described herein include features aimed at reducing the user-skin to electrode impedance values, thereby being able to provide functional levels of neurostimulation signals to a garment user based on identified safe thresholds of electrical signal current.

[0129] To illustrate, reference is made to FIG. 10, which illustrates a chart 1000 illustrating impedance amplitude against a spectrum of frequencies for various electrodes. FIG. 10 shows characterization of impedance amplitude of carbon electrodes 1010 against a spectrum of frequencies. The carbon-based electrodes may be configured primarily for generating bio-signal data, and may not be optimized for generating neurostimulation signals or signals for actuating features.

[0130] FIG. 10 shows characterization of impedance amplitude of embodiments of stainless steel electrodes coated with PEDOT:PSS ink 1020. FIG. 10 further shows characterization of impedance amplitude of embodiments of stainless-steel electrodes 1030.

[0131] The comparative characterization of impedance amplitude across a range of frequencies illustrates that a sufficiently suitable (or safe) window for providing neurostimulation signals (in terms of electrical current amplitude and pulse width) decreases with increasing user-skin to textile impedance. Accordingly, the carbon-based electrode characterization curve 1010 in FIG. 10 illustrates that the carbon-based electrode may not be suitable for safely providing neurostimulation signals for functional levels of neurostimulation to the garment user.

[0132] To illustrate features of various embodiments of textile electrodes of the present disclosure, some example textile electrodes will be described with experimental data. The experimental data is described to illustrate physical or electrical characterization of embodiments of textile electrodes.

[0133] The following materials, manufacturing apparatus, and software were utilized for constructing example textile electrodes.Materials:- Stainless steel microwires with polyester yarn (polyester 71% and SS 29%) for the conductive material (yarn linear density range: 60-400).PEDOT:PSS Ink for coating of conductive yarnNylon / spandex for the passive materialMedical grade snaps (stud & eyelet)Hydrogel electrodes (OUDYSCARE, Hong Kong).Equipment:STOLL ADF-530-32 BW E18V-bed flat knitting machine - 18 gaugeSTOLL ADF-530-32 BW E14V-bed flat knitting machine - 14 gaugeM228 ROTOWASH Launder-Ometer (SDL Atlas, SC, USA)Water-based lotion (Vaseline intensive care)PicoPress pressure measurement device (Microlab Elettronica SAS, Padua, Italy) - PalmSens4 (PalmSens, Houten, Netherlands)DS8R current controlled clinical grade stimulator (Digitimer, Hertfordshire, UK)\Nl USB-6002 low-cost DAQ board (National Instruments, US)RIGOL’s digital oscilloscope MSO1104z (RIGOL, Portland)Software:PSTrace 5.9-software (PalmSens, Houten, Netherlands)UltraScope software (RIGOL, Portland)MATLAB R2022a (MathWorks Inc., Natick, Massachusetts, USA)GraphPad Prism 9.4 (GraphPad Software, San Diego, California, USA)

[0134] In an embodiment, textile electrodes may be constructed with yarns interlaced with stainless-steel microwires for providing conductive functional material. In another embodiment, textile electrodes may be constructed with yarns with PEDOT:PSS coated stainless-steel based microwires providing conductive functional materials. In both examples, the microwires may provide reduced user-skin to electrode impedance for improved functional specifications for neurostimulation applications.

[0135] In some embodiments, coating yarns with PEDOT:PSS has been observed to improve the functional performance and conductivity of textile electrodes. In some examples, coated yarns may be developed based on a Roll-to-Roll coating techniques on fiber substrates for providing functional efficacy and longevity. In prototype tests, for textile electrodes constructed from both types of yarns, 3D knit textile electrodes (4.5 cm x 4 cm planar dimensions) were fabricated using 3D flat knitting to create flexible, breathable, and conformal interfaces with the skin.

[0136] For evaluating functional performance of textile electrode samples, user testing included: (1) measuring user-skin to textile electrode impedance; (2) characterizing motor responses to neurostimulation, including motor threshold, recruitment curve of induced movements up to full range of motion; (3) characterization of sensory responses to neurostimulation, including sensory thresholds, number of sensory level stimulation, along with participant survey feedback on types of sensation, comfort, or intensity.

[0137] Example 1 - Electrode Fabrication: Textile electrodes may be fabricated based on a V- bed flat knitting machine (Stoll, Ruetlingen, Germany). Two types of yarns may be used in the production process, both of which were composed of stainless steel (SS, diameter of 0.03 mm) microwires and polyester (polyester 71 % and SS 29%). One of the yarns may be coated with a biocompatible polymerpolyelectrolyte complex poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ink, at a coating rate of 150 pL / min, with a curing temperature of 190°C, and a coating speed of 20 RPM, using a roll-to-roll coating system (Aumann Espelkamp, DLH 170, Germany).

[0138] Example 2 - Skin Preparation for Dry Textile Stimulation Electrodes: To address challenges of utilizing textile electrodes in dry conditions, in some scenarios, a skin preparation including lotion was combined with the textile electrode application to the user skin. In example tests, applying lotion to the skin may improve the skin’s moisture content, may reduce the skinelectrode impedance, and may result in increased textile electrode contact with the user skin. In addition, molecular components in lotions may assist with attracting moisture from subdermal layers of the skin to maintain the moisture level over time.

[0036]

[0139] In contrast to oil-based lotions, experiments show that water-based lotions may decrease the impedance measured between the user skin and the textile electrode for up to 90 minutes.

[0037] Using water-based lotions on a user skin empirically show improved ECG data quality when generated by dry textile electrodes. Given observations relating to water-based lotions in lowering electrode-skin impedance, their wide availability and usage, moisturizing the skin was considered as the skin preparation method of choice for textile neurostimulation electrodes. To assess the potential variability in key properties such as conductivity depending on the choice of commercially available lotions, 10 different commonly used off-the-shelf lotions were selected and studied. Resulting measured impedance between the user skin and the textile electrode were quantified and compared with an oil-based lotion (negative control) as well as an electrode gel (positive control).

[0140] FIG. 11 illustrates a chart 1100 with characterization data showing impedance amplitude across a range of frequencies when a plurality of water-based lotions are utilized in testing, in accordance with embodiments of the present disclosure. In the experiments summarized in FIG. 11 , an oil-based location was utilized as a negative control test and a gel electrode was utilizedas a positive control test. The experiments included use of multiple textile electrode setups, including 8 water-based lotions (e.g., Vaseline™ 1102, Glysomed™ 1104, Aveeno™ 1106, CeraVe™ 1108, Cetaphil™ 1110, Lubriderm™ 1112, Neutrogena™ 1114, and Olay™ 1116), along side an electrode gel (SpectraGel 360™ 1118) as a control for comparison. Vaseline used as a water-based lotion yielded the greatest observe difference to the observed results of the electrode gel, in comparison to other water-based lotions. Accordingly, Vaseline as a water-based lotion was used in for determining efficacy of embodiments of the present disclosure.

[0141] Example 3 - Skin-electrode impedance measurements of textile electrodes versus hydrogel electrodes: In experiments for electrically characterizing embodiments of textile electrodes for neurostimulation, the user-skin to textile impedance was measured for 12 users. For experiments, to investigate the effect of water-based lotions as a skin preparation, the skinelectrode impedance was measured with no lotion I skin preparations applied. Further, hydrogel stimulation electrodes were tested alongside textile electrodes as a control experiment group.

[0142] As illustrated in FIG. 11 , testing where water-based lotions were used in combination with a textile electrode yielded electrical conductivity results similar to electrical conductivity results when a gel electrode is used. For further user testing, the water-based lotion with the lowest conductivity was chosen to represent a worst-case-scenario among the investigated options. This approach was pursued to enable generalize the on-body functional test findings across investigated water-based lotions.

[0143] FIG. 12 illustrates a chart 1200 of characterization data showing impedance amplitude across a range of frequencies for a series of embodiments of textile electrodes, in accordance with embodiments of the present disclosure. For example, various setups were characterized, including: (a) hydrogel electrodes 1202; (b) stainless-steel electrodes without Iotion1204; (c) PEDOT:PSS coated stainless steel electrodes without lotion 1206; (d) stainless-steel electrodes with lotion as a skin preparation 1208; and (e) PEDOT:PSS coated stainless-steel electrodes with lotion as a skin preparation 1210. FIG. 12 illustrates average skin-electrode impedance with standard deviation.

[0144] Statistical comparisons observed at 5000 Hz based on a presumption of typical neurostimulation waveforms with a 200ps pulse width. In experiments, one data point for SSelectrodes without lotion was removed from the analysis as it was identified as an outlier. The average skin-electrode impedance at 5000 Hz was 602.9 ohms ± 149.4 ohms for hydrogel electrodes, 47655 ohms ± 37606 ohms for SS electrodes in dry condition, and 34020 ohms ± 12080 ohms for PEDOT:PSS coated SS electrodes in dry condition. With lotion applied to the skin, the average skin-electrode impedance at 5000 Hz was 12544 ohms ± 5237 ohms for SS electrodes and 9843 ohms ± 2432 ohms for PEDOT:PSS coated SS electrodes.

[0145] Without lotion applied to the skin, no statistically significant difference was found between the two textile electrodes (p-value of 0.7289). Similarly, no statistically significant difference was found between the two textile electrodes with lotion applied to the skin (p-value of 0.1161). However, a statistically significant difference was found for hydrogel electrodes in comparison to SS electrodes and PEDOT:PSS coated SS electrodes without lotion (p-values of 0.0003 and <0.0001 , respectively), and in comparison to SS electrodes and PEDOT:PSS coated SS electrodes with lotion applied to the skin (p-values of <0.0001). In addition, a statistically significant difference was found between SS electrodes with and without lotion (p-value of 0.0011), and between PEDOT:PSS coated SS electrodes with and without lotion (p-value < 0.0001). Overall, when a skin preparation, such as a lotion was used, the observations showed lower average impedance values for both textile electrodes tested.

[0146] FIG. 13 illustrates a chart 1300 showing average impedance values at 5,000 Hz for the textile electrode configuration discussed above with reference to FIG. 12. The chart 1300 illustrates impedance amplitude data for experiments conducted with hydrogel electrodes 1302, stainless steel electrodes (dry) 1304, PEDOT stainless steel electrodes (dry) 1306, stainless steel electrodes with lotion 1308, and PEDOT stainless steel electrodes with lotion 1310.

[0147] Example 4 - Sensorimotor response characterization of textile electrodes versus hydrogel electrodes: To assess the functionality of the embodiments of textile electrodes, sensorimotor responses of the textile electrodes were evaluated compared to hydrogel electrodes in 12 user participants (6 female, 6 male). Tests were carried out based on a pair of respective textile electrode type on the anterior surface of the forearm.

[0148] To characterize the evoked sensory responses, a plurality of stimulation parameters were investigated: detection threshold (DT), motor threshold (MT), full motor threshold (FMT), justnoticeable difference (JND), Weber’s fraction, and the number of stimulation levels (number of levels). DT may be the minimum current amplitude that is needed to sense electrical stimulation

[0039] , MT may be the minimum current amplitude needed to initiate motion in the wrist. FMT may be the minimum current amplitude needed for a visible full range of motion for a wrist flexion

[0040] , JND may be the smallest difference in current amplitude that provides a noticeable difference in sensation, which indicates the sensitivity of the subject to the sensation induced by electric stimulation

[0039] , Weber’s Fraction may be a measure of normalized JND to DT, to clearly show the sensitivity to stimulation between different subjects and different electrodes tested. The number of levels may indicate the feedback resolution, where a higher number of levels correlates to a better ability to differentiate sensation between two pulses

[0039] , In addition to these parameters, a survey was conducted for each type of electrode to capture the user's perception of the stimulation comfort, stimulation intensity, location of sensation and description of sensation.

[0149] To characterize motor responses evoked by neurostimulation, stimulation amplitude was gradually increased from the motor threshold all the way to the full range of motion (wrist flexion).

[0150] FIG. 14 illustrates a recruitment curve 1400 of a stimulation response for a wrist flexion motion, in accordance with embodiments of experiment tests of textile electrodes. In the respective experimental tests, the angle at respective electrical current increments may be measured from the resting position to a maximum angle or full range of motion at that increment. Kinematic recruitment curves 1400 for the evoked wrist flexion movements were tracked and are illustrated in FIG. 14. Respective tests were carried out using hydrogel electrodes as a control group for textile electrodes.

[0151] Reference is made to FIG. 15, which illustrates a kinematic recruitment curve 1500 across various subjects. In all subjects and for all electrodes, full range of motion was achieved without discomfort or pain. The electrodes under sensorimotor response test included hydrogel electrodes, stainless-steel textile electrodes, and PEDOT:PSS coated stainless-steel textile electrodes. In FIG. 15, the curve illustrates kinematic recruitment curves for the wrist flexion. The X-axis is normalized to motor threshold.

[0152] FIG. 16 illustrates charts 1600 showing metrics and survey results of evoked sensory responses. The charts 1600 illustrate data associated with hydrogel electrodes (A), PEDOT: PSS Coated stainless steel electrodes (B), and stainless steel electrodes (C). In chart (b) of FIG. 16, the average DT, MT, FMT, JND, Weber’s fraction and number of levels is shown. In chart (c) of FIG. 16, average scores for the intensity of stimulation and comfort level of the stimulation is shown. In chart (d), distribution of the survey responses for perceived location of stimulation evoked sensation is shown. In chart (d) distribution of the survey responses for perceived location of stimulation evoked sensation is shown. In chart (e), distribution of the survey responses for the description of perceived stimulation evoked sensation is shown.

[0153] Table 2 provides metrics of evoked sensory responses presented in form of average ± standard deviation, and in particular sensorimotor response of textile electrodes versus hydrogel electrodes.Table 2:

[0154] Overall, in the above-described experiments, where were no statistically significant differences found in investigated metrics across electrode types, including DT, MT, FMT, JND, Weber’s Fraction, number of levels, stimulation intensity, and stimulation comfort (p-value > 0.05). Further, stimulation was perceived by subjects similarly between textile electrodes and hydrogel electrodes, where stimulation was mostly sensed locally around the electrodes in the form of vibration and tingling sensation.

[0155] Example 5 - Effect of Lotion Over 6 Hours of Use With PEDOT: PSS Coated SS Electrodes: As water-based lotions as a skin preparation method for combination with dry textile stimulation electrode use is described herein, the wear-off effect of the lotion and the duration ofuse for the electrodes to provide a comfortable stimulation was investigated. After applying lotion to the skin and donning the electrodes, 12 subjects (6 female, 6 male) were tested with PEDOT:PSS coated SS electrodes, where skin-electrode impedance measurements and neurostimulation responses were gathered immediately after applying lotion and every 2 hours for up to 6 hours.

[0156] FIG. 17 illustrates charts 1700 showing user-skin to textile impedance measurements, in accordance with embodiments of experiments for characterizing textile electrodes. Duration of time of 0 hours is indicated with the letter A, duration of time of 2 hours is indicated with letter B, duration of time of 4 hours is indicated with letter C, and duration of time of 6 hours is indicated with letter D. The average impedance at 5000 Hz was 7063 I ± 1964 I for 0 hours testing (immediately after applying lotion), 8670 I ± 3313 I for 2 hours testing, 9128 I ± 2945 I for 4 hours testing, and 10763 I ± 4695 I for 6 hours testing. A statistically significant difference was found for impedance between 0 and 6 hours of testing (p-value of 0.0343) and between 2 and 6 hours testing (p-value of 0.0241). No statistically significant difference was observed between the other timepoints (p-values > 0.05). Results across 4 time points of testing immediately after applying lotion, and every 2 hours for up to 6 hours was conducted to examine the effect of lotion over time with PEDOT:PSS Coated SS electrodes. In chart (a), an average skin-electrode impedance with standard deviation is shown. In chart (b), average impedance values at 5,000 Hz is shown.

[0157] Table 3 (below) includes measured metrics of sensory evoked stimulation responses over 6 hours of testing. The table depicts the defect of lotion on sensory evoked responses over 6 hours of use with PEDOT:PSS Coated stainless-steel textile electrodes.TABLE 3:

[0158] FIG. 18 illustrates a chart 1800 and FIG. 19 illustrate charts 1900 collectively showing kinematic recruitment curves of stimulation-evoked wrist flexion, the intensity and comfort of stimulation, the location of stimulation sensation, and the description of sensation, respectively. For ease of illustration, in FIG. 19, duration of time of 0 hours is indicated with the letter A, duration of time of 2 hours is indicated with letter B, duration of time of 4 hours is indicated with letter C, and duration of time of 6 hours is indicated with letter D.A statistically significant difference was only found for the comfort level between 0 and 2 hours testing (p-value of 0.0142). However, the average comfort level at the 0 hour testing was a score of 2.8 and a score of 3.3 at the 2 hours testing, where both values correspond to a comfortable stimulation response. In addition, no statistically significant difference was found for comfort level between the 0, 4 and 6 hours testing (p-values > 0.05). Neurostimulation was also perceived similarly across the 4 timepoints: sensed locally around the electrodes and mainly in the form of vibration and tingling sensations.

[0159] In FIG. 18, recruitment curves for the wrist flexion are shown. FIG. 19, chart (d) shows average scores for the intensity of stimulation and comfort level of the stimulation. Chart (e) shows a distribution of survey responses for perceived location of stimulation evoked stimulation. Chart (f) shows a distribution of survey responses for description of the perceived stimulation evoked stimulation.

[0160] Example 6 - Wash Durability of SS Electrodes and PEDOT:PSS Coated SS Electrodes: One of the potential advantages of embodiments of textile neurostimulation electrodes solutions described herein may be reusability compared to example gel electrode solutions. To investigate the durability of our proposed textile electrodes, the effect of residential wash cycles on the functional characteristics and performance of the electrodes was investigated.

[0161] To assess the wash durability, 6 stainless-steel electrodes and 6 PEDOT:PSS coated stainless-steel electrodes were used for testing at an unwashed condition, after 15 washes, and after 30 washes. The functional durability when undergoing residential wash cycles was assessed in terms of their skin-electrode impedance, voltage transient measurements, and stimulation response for 6 subjects (3 female, 3 male).

[0162] FIG. 20 illustrates charts 2000 showing average skin-electrode impedance results of SS electrodes and PEDOT:PSS coated SS electrodes, in accordance with embodiments of the present disclosure. The charts show results for unwashed electrodes, electrodes after 15 washes, and electrodes after 30 washes for stainless-steel and PEDOT:PSS coated stainless-steel electrodes. Chart (a) shows average skin-electrode impedance of stainless-steel and PEDOT:PSS coated SS electrodes. Chart (b) shows the average impedance at 5,000 Hz. Chart (c) shows peak voltage transient values at 7 mA.

[0163] For unwashed electrodes, the average impedance at 5000 Hz was 3878 Q ± 711 Q for SS electrodes and 3655 Q ± 743 Q for PEDOT:PSS Coated SS electrodes. After 15 washes, the average impedance at 5000 Hz was 4364 Q ± 1667 Q for SS electrodes and 3955 Q ± 1240 Q for PEDOT:PSS Coated SS electrodes. After 30 washes, the average impedance at 5000 Hz was 3588 Q ± 884 Q for SS electrodes and 3850 Q ± 847 Q for PEDOT:PSS Coated SS electrodes. No statistically significant difference was found between SS electrodes and PEDOT:PSS Coated SS electrodes across wash conditions (p-values > 0.05). In addition, no statistically significant difference was found between unwashed electrodes, electrodes with 15 washes, and electrodes with 30 washes for either of the textile electrode types (p-values > 0.05).

[0164] In FIG. 20, chart (c) shows the peak voltage transient values for SS electrodes, and PEDOT:PSS Coated SS electrodes across 30 wash cycles. For unwashed electrodes, the average peak voltage transient at 7 mA was 63.6 V ± 23.3 V for SS electrodes, and 58.1 V ± 17.4 V for PEDOT:PSS Coated SS electrodes. After 15 washes, the average peak voltage transient at 7 mA was 63.0 V ± 19.7 V for SS electrodes and 75.7 V ± 23.0 V for PEDOT:PSS Coated SS electrodes. After 30 washes, the average peak voltage transient at 7 mA was 62.3 V ± 12.2 V for SS electrodes and 64.9 V ± 12.7 V for PEDOT:PSS Coated SS electrodes. No statistically significant difference was found for peak voltage transient values across the wash conditions tested and between the two textile electrodes (p-values > 0.05).

[0165] Table 4 (below) shows average values for stimulation parameters, including DT, MT, FMT, JND, Weber’s Fraction, the number of levels, the intensity of stimulation, and the comfort of stimulation. For all these parameters, no statistically significant difference was found between the wash conditions for both textile electrodes (p-values > 0.05).Table 4 (below): effect of washability of stainless-steel electrodes and PEDOT:PSS Coated SS electrodes unwashed, after 15 washes and after 30 washes

[0166] FIG. 21 illustrates charts 2100 showing recruitment curves of wrist flexion, in accordance with embodiments of the present disclosure. Overall, stimulation was perceived by subjects similarly across the three wash conditions for both textile electrodes, where stimulation was sensed locally around the electrodes for all subjects, mainly in the form of vibration, tap, and tingling sensation. For chart (d), kinematic recruitment curves for the wrist flexion is illustrated. The X-axis is normalized to the motor threshold.

[0167] FIG. 22 illustrates a chart 2200 showing a voltage transient response of the subjects at 7 mA. Chart (b) shows an average peak voltage transient at 7 mA per electrode type. The average peak voltage transient value was 14.15 V ± 2.4 V for hydrogel electrodes, 63.60 V ± 23.28 V for SS electrodes, and 58.14 V ± 17.41 V for PEDOT:PSS coated SS electrodes. Statistically significant difference was found for hydrogel electrodes in comparison to SS electrodes and PEDOT:PSS coated SS electrodes (p-values of 0.0011 and 0.0004, respectively).

[0168] In FIG. 22, the voltage transient measurements of hydrogel electrodes, SS electrodes, and PEDOT : PSS SS electrodes are shown in chart (a) as being average responses for stimulation at 7 mA for 6 subjects tested. Chart (b) shows average peak voltage transient response at 7 mA for hydrogel electrodes and two embodiments of textile electrodes described in the present disclosure.

[0169] Example testing operations details for embodiments of textile electrodes described in the present disclosure are provided below.

[0170] Study Subjects: To characterize embodiments described in the present disclosure, testing operations included 4 experimental tests that involved participants across different tests but consistent within the tests, due to limited availability of the participants. Overall, 21 users were involved in this research, including 11 male subjects (age 28.7 ± 4.5) and 10 female subjects (age 26.3 ± 3.8). The research ethic board at the University of Toronto approved the experimental procedures conducted, and consent to the experimental tests was provided by subjects. Exclusion criteria included no electronically implanted devices and no broken skin on the tested arm.

[0171] Skin Preparation: For safe delivery of electrical stimulation, a water-based lotion was applied to the skin prior to donning of dry textile electrodes. For a pair of textile electrodes, about 2 fingertip units (FTUs) or 1 gram of lotion was applied to the arm where electrodes were placed. The skin lotion used was Vaseline™ intensive care for all on-body tests.

[0172] Electrode Placement: All on-body electrode tests were carried out on the anterior surface of the forearm. The textile electrode placement included positioning a pair of electrodes over the flexor carpi radialis muscle, with the cathode placed over the muscle belly, and the anode 6 cm distally (center to center). Location of the electrodes were determined by manual palpation. For all tests with textile electrodes, the contact pressure was measured to be between 15 to 20 mmHg using a PicoPress pressure measurement device (Microlab Elettronica SAS, Padua, Italy). This was performed to ensure adequate and consistent contact pressure between the skin and the electrode in all tests, as typically suggested for textile electrodes

[0024] , For tests involving hydrogel electrodes, commercially available stimulation hydrogel electrodes with dimensions of 5 cm x 5 cm were used (OUDYSCARE, Hong Kong). In some embodiments of textile electrodes described in the present disclosure, a contact pressure of greater than 10 mmHg may be desirablefor providing desired neurostimulation to the textile electrode user. Other contact pressure requirements may be desirable for varying applications of the textile electrode.

[0173] Skin-Electrode Impedance: PalmSens4 (PalmSens, Houten, Netherlands) was utilized to record impedance frequency sweep, through a frequency range of 1 Hz to 200,000 Hz with 5 measurements per decade. To acquire the impedance data, PSTrace 5.9-software by PalmSens was used. The setup followed a current range of 100 nA to 10 mA and a sinusoidal voltage supply of 0.25 V. A 2 electrode setup was used, where the proximal electrode was connected to the working / sensing electrodes, and the distal electrode was connected to the counter / reference electrode.

[0174] Stimulation Response: A DS8R current controlled clinical grade stimulator was used (Digitimer, Hertfordshire, UK). The stimulator was configured to provide current that is a biphasic charge-balance symmetric rectangular waveform with normal positive polarity, phase width of 200 ps. Nl USB-6002 low-cost DAQ board was used to create an external trigger that provides a train of 40 Hz pulses (National Instruments, US). The stimulation response testing was divided into four sections. Section one determined DT. It was obtained by providing stimulus at 0 mA, and gradually increasing by 0.3 mA until the stimulus was perceived. This approximate DT was then used in a staircase procedure to increase or decrease the stimulus by 0.1 mA for 30 iterations to tune and find the average DT that was sensed by the individual [39,49],

[0175] In some experiments described herein, when testing textile electrodes, testing operations determined the range of motion of an individual by provoking a wrist flexion. The stimulus was increased gradually by 0.3 mA from the DT until motion was provoked to obtain the MT. To obtain the range of motion, the stimulus continued to increase gradually by 0.3 mA until full range of motion was achieved visually, to obtain FMT

[0040] ,

[0176] To obtain the angle of wrist flexion, images of the motion were obtained for every increment using a webcam pointed directly towards the movement. If pain was felt at any point in this test, the test would have been terminated and the value of current amplitude would have been recorded as the pain threshold (PT)

[0039] , However, this did not occur in any of the tests reported in this study on any of the participants.

[0177] In some experiments described herein, operations determined the JND by providing two pulses of the same or different amplitude, and feedback was obtained from the subject if a difference in intensity was perceived. The first pulse was the “baseline pulse” which was set to be 0.5 mA higher than DT. The second pulse was either equal or higher in amplitude than the baseline pulse, delivered after a wait time of 1 second. The limit of the current amplitude of the second pulse was set to be up to either the MT amplitude or 2.5 mA higher than the baseline pulse. 110 randomly generated pulse combinations were used to determine the JND. JND was calculated as the lowest current amplitude of the second pulse where a difference in sensation is perceived at least 50% of the trials at that current amplitude. The Weber’s fraction was computed as follows:Weber's Fraction (k) = ( / ND - DT) / DT

[0178] Another metric was computed utilizing the Weber’s fraction to find the number of stimulation levels between DT and MT using a recursive equation

[0039] , The number of levels was computed as follows: In = ln-1 + ln-1 X k

[0039] , where I is the current amplitude, the first term was set to DT and the limit is set to current exceeding MT.

[0179] In some experiments described herein, operations determined the sensation quality using a 1 second train of pulses at the MT current amplitude

[0039] , A questionnaire was provided to the participants to address the sensation feeling, the location of sensation, comfort level and intensity of stimulation [39,50], For the comfort level of stimulation, a likert-type scale was used, where 1 represents very comfortable stimulation and 7 represents very uncomfortable stimulation. For the intensity of the stimulation, a numerical rating scale was used, where 0 represents no intensity stimulation and 10 represents painful stimulation.

[0180] Beside the parameters described herein, images of the wrist flexion motion were analyzed for every increment of current between and including MT and FMT. The wrist flexion angles were computed by finding the difference in wrist flexion angle between the resting position image and the full range of motion (ROM) image for every current increment tested. This was done using the angle tool in the imageJ program (National Institute of Health, US). The angles computed were then used to generate kinematic recruitment curves of wrist flexion angles againststimulation amplitudes that are normalized to MT value per test conducted. FIG. 14 illustrated a recruitment curve and an illustration of how each angle value was calculated between the resting position and the range of motion (ROM) position.

[0181] Voltage Transient Measurements: A 1-second long train of pulses at 7 mA was provided while recording the voltage potential across the pair of electrodes. To measure the electric potential, a RIGOL’s digital oscilloscope MSO1104z was used (RIGOL, Portland). To record the data, UltraScope software was used and connected to the oscilloscope (RIGOL, Portland).

[0182] Electrode Washing Procedure: The textile electrodes were washed according to the American Association of Textile Chemists and Colourists (AATCC) home laundry washing test method 61-2009, test No. 2A, using a M228 ROTOWASH Launder-Ometer (SDL Atlas, SC, USA)

[0051] , After washing the electrodes, they were left to dry at room temperature prior to testing.

[0183] Bench Testing of Water-Based Lotions: Eight commercially available water-based lotions were obtained and tested for impedance as a method to compare their conductivity. The test involved placing 7 mL of each lotion in a small container and then placing two jumper wires in the lotion at opposite ends of the container to connect to PalmSens4 cables for impedance measurements. Lotions tested included 1) Vaseline™ intensive care (unscented); 2) Glysomed™ fragrance free hand cream; 3) Aveeno™ body lotion unscented cream for dry skin; 4) Olay™ firming & hydrating body lotion with collagen and vitamin B3; 5) Cetaphil™ daily hydrating lotion with hyaluronic acid; 6) CeraVe™ daily moisturizing lotion with hyaluronic acid; 7) Lubriderm™ advanced moisture therapy moisturizing cream; and 8) Neutrogena™ formula daily body moisturizer. One gel based formula, Spectra™ 360 Electrode Gel, was used as a positive control.

[0184] Data Analysis: Data analysis for tests were conducted were performed in MATLAB R2022a (MathWorks Inc., Natick, Massachusetts, USA). Statistical analyses were conducted using GraphPad Prism 9.4 (GraphPad Software, San Diego, California, USA), using repeated measures one-way or two-way ANOVA with Tukey tests with a significance threshold set to p < 0.05. Outlier testing was also performed on the data collected using Grubbs’s test with alpha of 0.01.

[0185] The present disclosure describes embodiments of textile electrodes for providing neurostimulation applications. Embodiments of textile electrodes may be configured for otherapplications for providing actuating feedback or output to a textile garment user. Testing operations described herein illustrated the comfort and functional effectiveness of embodiments of stainless-steel textile electrodes and PEDOT:PSS coated stainless-steel textile electrodes in evoking motor responses up to at least full-range of motion, similar to the gold-standard hydrogel electrodes. Further, functional test operation described herein of sensory evoked responses demonstrated that both textile electrode types may produce similar responses relative to each other and to that of the gold standard hydrogel electrodes for all metrics. Textile electrodes and hydrogel electrodes may provide comparable perceived sensations when users were surveyed for comfort, intensity of stimulation, and the type of evoked sensation.

[0186] Results of testing operations described herein demonstrate comfort and effectiveness of textile neurostimulation electrodes across a range of sensorimotor applications of neurostimulation such as FES for rehabilitation, assistive neuroprosthetic devices, as well as applications of electrical stimulation for sensory substitution. Additionally, the demonstrated functional similarity of the proposed textile electrodes to that of the gold standard hydrogel electrodes shows that embodiments of textile electrodes of the present disclosure may be suitable candidate devices for clinical usage, in lieu of example gel electrode devices.

[0187] Testing operations described herein demonstrated reusability and functional durability of embodiments of textile electrodes herein through an investigation of the effect of wash cycles. For embodiments of stainless-steel textile electrodes, skin-electrode impedance values did not increase significantly or show a pattern of increasing for the investigated 30 washes I laundry cycles. In addition, similar sensorimotor stimulation responses and perceived sensation surveys were obtained with electrodes immediately after washing, after 15 washes, and after 30 washes.

[0188] In some situations, a practical challenge of neurostimulation interventions that require frequent use by the patients is the need for proper placement and targeting of the stimulation electrodes over the treatment sites. The scalability and design flexibility of the proposed textile electrodes that were developed using programmable knitting machines, allowing embodiments of textile electrodes described herein to be embedded in garments of various sizes. Such embodiments of textile electrodes may be positioned about the textile garment to promote consistent textile electrode placement against a user’s skin over multiple garment usages.

[0189] The present disclosure describes textile electrodes that may be fabricated using a V- bed flat knitting machine (Stoll, Ruetlingen, Germany). In some embodiments, at least one of two types of yarn may be used for fabricating textile electrode devices. In some embodiments, the textile electrodes may be configured with stainless steel (diameter of 0.03 mm) microwires and polyester (71% polyester and 29% SS).

[0190] In some embodiments, one of the yarns may be coated with a biocompatible polymer: polyelectrolyte complex poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ink, at a coating rate of 150 uL min-1, with a curing temperature of 190°C, and a coating speed of 20 RPM, using a roll-to-roll coating system (Aumann Espelkamp, DLH 170, Germany).

[0191] In some scenarios, to configure for desirable skin-electrode contact, textile electrode devices may be configured as a three-dimensional structure, thereby elevating the conductive surface of the electrode above the electrically non-conductive base fabric. The three-dimensional structure may promote a uniform surface contact during wear. The surface of the electrode may be constructed of pristine or coated yarn. In some embodiments, a spacer layer may be knitted beneath a surface and may comprise polyester yarn to provide a three-dimensional shape or profile. In some embodiments, a base or back layer may be constructed of nylon yarn. In some embodiments, a front and back layer of surrounding fabric of an electrode, with a double jersey structure, may be constructed with nylon / spandex yarns. In some scenarios, nylon may be used for the base fabric due to its comfort-oriented and durability properties. It may be appreciated that textile electrode devices may be constructed of other materials such as cotton.

[0192] In some embodiments, textile electrode devices may be configured to deliver desirable electrical stimulation to a user skin using a water-based lotion prior to donning of the dry textile electrode. For example, for a pair of textile electrodes, approximately 2 finger-tip units (FTLIs) or 1 gram of lotion may be applied to an arm adjacent to where textile electrode devices may be placed.

[0193] To characterize embodiments of textile stimulation electrodes, Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) measurements, thermal conductivity measurements, breathability tests, and fatigue analysis may be conducted.

[0194] FIG. 23 illustrates a chart 2300 showing FTIR-ATR spectra for uncoated and PEDOT:PSS coated SS yarns. The resulting data illustrates an increase in the relative absorbance of the characteristic 0=0 stretching from both PEDOT and PSS at absorbance bands of 792, 847, and 970 cm-1. Further, an increase in absorbance was shown at 1180 cm-1.

[0195] In some experiments, thermal conductivity of embodiments of textile electrodes were measured to be 0.083 Wnr1K’1for stainless steel electrodes and 0.078 Wm’1k’1for PEDOT:PSS coated stainless steel electrodes.

[0196] In some experiments, breathability characterization was conducted by measuring permeability ot water vapor over time. FIG. 24 illustrates a chart 2400 showing water permeability of the developed electrodes compared to hydrogel electrodes over a duration of 28 hours. In some experiments, water-vapor transmission rates (WVTR) of the hydrogel electrodes as 0 gm-2h'1, indicating the hydrogel electrodes are not breathable.

[0197] To assess fatigue response of embodiments of textile electrodes, textile electrode samples may be stretched at a rate of 100 mm / min until they reached a breaking point. FIG. 25 illustrates a chart 2500 showing stress-strain curves of embodiments of textile electrodes under constant strain rate of 100 mm min-1until a breaking point.

[0198] FIG. 26 shows a chart 2600 illustrating a fatigue response of embodiments of textile electrodes, where fatigue strength was observed after 586 cycles at 10.5 MPa for stainless steel electrodes and after 481 cycles at 15 MPa for PEDOT:PSS coated SS electrodes. For example, FIG. 26 illustrates fatigue behavior of the developed electrodes under 50% of their breaking strain for 1000 cycles. The data readings are illustrated as dots and fitted to a curve.

[0199] To evaluate functional properties of embodiments of textile electrodes after fatigue testing, FIG. 27 illustrates a chart 2700 of skin-electrode impedance measurements performed with electrodes on 6 participants (three female, three male). Chart 2700 illustrates data representing skin-electrode impedance (at 5000 Hz) (n=6 participants) of developed electrodes before stretching and after stretching for 1000 cycles at 50% of their breaking strain. For both electrode types, no observed statistically significant difference was found in the skin-electrode impedances between unstretched electrodes and those that had undergone 1000 stretch cycles.

[0200] The term “connected” or "coupled to" may include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements).

[0201] Although the embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope. Moreover, the scope of the present disclosure is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification.

[0202] As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

[0203] The description provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

[0204] As can be understood, the examples described above and illustrated are intended to be exemplary only.

[0205] Applicant notes that the described embodiments and examples are illustrative and nonlimiting. Practical implementation of the features may incorporate a combination of some or all of the aspects, and features described herein should not be taken as indications of future or existing product plans. Applicant partakes in both foundational and applied research, and in some cases, the features described are developed on an exploratory basis.REFERENCES

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Claims

WHAT IS CLAIMED IS:

1. A textile device comprising: a base layer; a spacer-layer coupled to the base layer configured to provide a raised textile profile relative to the base layer; and a user-facing layer coupled to the spacer-layer constructed of a knitted combination of non-conductive fibers and stainless-steel wires for interfacing with user skin, the stainless-steel wires electrically coupled to a computing device.

2. The textile device of claim 1 , wherein the knitted combination of non-conductive fibers and stainless-steel wires includes polyester yarn and stainless-steel microwires.

3. The textile device of claim 1, wherein the stainless-steel wires have a diameter of approximately 0.03 millimeters.

4. The textile device of claim 1, wherein a composition of the knitted combination includes approximately 70% to 80% polyester yarn.

5. The textile device of claim 1 , wherein the composition of the knitted combination includes approximately 71% polyester yarn and 29% stainless-steel wires.

6. The textile device of claim 1, wherein the stainless-steel wires are coated with a biocompatible polymer: polyelectrolyte complex poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ink.

7. The textile device of claim 6, wherein the stainless-steel wires are coated with the PEDOT:PSS ink at a coating rate of 150 pL / min, with a curing temperature of approximately 190°C, and a coating speed of 20 RPM, based on a roll-to-roll coating system.

8. The textile device of claim 1 , comprising a water-based preparation solution configured to be applied to the user-facing layer for reducing skin to textile impedance.

9. The textile device of claim 1, wherein the knitted combination is based on a stitch density in the range of 80 to 150 courses per centimeter (cpc) x wales per centimeter (wpc).

10. The textile device of claim 1 , wherein the knitted combination is based on stitch lengths in the range of 1.8 millimeters to 6.4 millimeters.

11. The textile device of claim 1 , wherein the knitted combination includes a symmetric knit pattern in at least one of a horizontal direction or a vertical direction.

12. The textile device of claim 1 , wherein the knitted combination includes a tight knit loops with minimal gaps among the series of tight knit loops.

13. The textile device of claim 1 , wherein the spacer-layer includes a knitted non-conductive polyester yarn.

14. The textile device of claim 1 , wherein the base layer includes a nylon yarn interlaced with a textile body, wherein the textile body is constructed of a double jersey structure including nylon / spandex yarns.

15. The textile device of claim 1 , wherein the computing device includes: a processor; and a memory storing processor-executable instructions that, when executed, configure the processor to: detect one or more signals based on electrical signals conducted by the stainless- steel microwires; and generate one or more data signals representing physiological data based on a skin-to-textile interface at the user skin.

16. The textile device of claim 1 , wherein the computing device includes a processor; and a memory storing processor-executable instructions that, when executed, configure the processor to: generate an electrical signal representing a neurostimulation signal; and transmit the electrical signal representing the neurostimulation signal across to the coupled stainless-steel wires for providing a neurostimulation signal at the skin-to-textile interface.

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