Nanofiber electrodes with changing three-dimensional shape

Abstract

A nanofiber electrode can be provided. The nanofiber electrode may include a first nanofiber layer and a second nanofiber layer. The nanofiber electrode may further include one or more conductive power supply paths sandwiched between the first nanofiber layer and the second nanofiber layer. At least one of the first nanofiber layer or the second nanofiber layer may be configured to absorb and expand a liquid when exposed to the liquid, thereby changing the three-dimensional shape of the nanofiber electrode.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 351738, filed on June 13, 2022, which is hereby incorporated by reference in its entirety. This disclosure relates to nanofiber electrodes that can change their own three - dimensional shape to conform to, for example, the contour of biological tissue.

Background Art

[0002] Electrodes are used medically to measure the electrical parameters of tissue and / or to apply electrical stimulation to tissue. However, there are many challenges in using electrodes for medical purposes. Tissues have different shapes and sizes and generally do not have smooth contours. Furthermore, tissues do not provide the electrode with a latch structure or any other type of coupling function. Additionally, electrodes must be biocompatible so as not to generally have an adverse effect on the tissues and homeostasis of the human body. The electrodes should also have sufficient insulation and toughness to withstand the influence of the liquid surrounding the tissue.

Summary of the Invention

[0003] In some embodiments, a nanofiber electrode can be provided. The nanofiber electrode may include a first nanofiber layer and a second nanofiber layer. The nanofiber electrode may further include one or more conductive power supply paths located between the first nanofiber layer and the second nanofiber layer. At least one of the first nanofiber layer or the second nanofiber layer may be configured to absorb and expand a liquid when exposed to the liquid, thereby changing the three - dimensional shape of the nanofiber electrode. In some embodiments, a method for fabricating a nanofiber electrode can be provided. This method may include the step of forming one or more conductive power supply paths on a first nanofiber layer using a patterned film, wherein the patterned film defines the shape of one or more conductive power supply paths such that at least a portion of one or more conductive power supply paths is located between the first nanofiber layer and the second nanofiber layer, and at least a portion of one or more conductive power supply paths is covered by the second nanofiber layer. At least one of the first or second nanofiber layer may be configured to absorb a liquid and expand when exposed to a liquid, thereby changing the three-dimensional shape of the nanofiber electrode. In some embodiments, a method for using a nanofiber electrode can be provided. This method may include the step of placing the nanofiber electrode in tissue, the nanofiber electrode having a first nanofiber layer, a second nanofiber layer, and one or more conductive power supply paths located between the first and second nanofiber layers. The method may also include the step of exposing the nanofiber electrode to biological fluids near the tissue, causing at least one of the first or second nanofiber layers to absorb the biological fluids and expand, thereby changing the three-dimensional shape of the nanofiber electrode, the changed three-dimensional shape conforming to the contour of the tissue. [Brief explanation of the drawing]

[0004] [Figure 1] This figure shows an exemplary biological environment according to an exemplary embodiment of this disclosure. [Figure 2A] This figure shows an exemplary method for fabricating nanofiber electrodes according to an exemplary embodiment of this disclosure. [Figure 2B] This figure shows the progress of the fabrication process according to an exemplary embodiment of this disclosure, following the steps discussed in the method of Figure 2A. [Figure 3A]This figure shows an exemplary method for generating a nanofiber layer to be used in a nanofiber electrode, according to an exemplary embodiment of this disclosure. [Figure 3B] This figure shows the progress of nanofiber layer formation through the discussed steps of the method in Figure 3A, according to an exemplary embodiment of this disclosure. [Figure 4] This figure shows the shape change characteristics of a nanofiber layer produced using the method shown in Figures 3A-3B according to an example embodiment of this disclosure. [Figure 5A] This figure shows an exemplary method for producing a nanofiber substrate from a biomass material, according to an exemplary embodiment of this disclosure. [Figure 5B] This figure shows the progress of nanofiber substrate production in a factory setting using the steps discussed in the method of Figure 5A. [Figure 6] This figure shows an exemplary biomass material for constructing a nanofiber substrate for nanofiber electrodes, according to an exemplary embodiment of this disclosure. [Figure 7] This figure shows an exemplary migration between wet and dry carbon nanotube electrodes according to an exemplary embodiment of this disclosure. [Figure 8] This figure shows another exemplary migration between wet and dry silver nanowire electrodes according to an exemplary embodiment of this disclosure. [Figure 9] This figure shows an exemplary method using nanofiber electrodes according to an exemplary embodiment of this disclosure. [Modes for carrying out the invention]

[0005] The figures are intended to illustrate exemplary embodiments, but it should be understood that this disclosure is not limited to the arrangements and means shown in the drawings. In the figures, the same reference numerals indicate at least generally similar elements. The embodiments disclosed herein generally relate to nanofiber electrodes that can change their own three-dimensional shape to conform to the contour of biological tissue. For example, a substantially planar nanofiber electrode may be placed in biological tissue having a substantially rounded contour, such as blood vessels, and the nanofiber electrode can change its substantially planar shape to a substantially annular three-dimensional shape. This three-dimensional shape change not only conforms to the contour of the biological tissue but also provides a coupling function between the biological tissue and the nanofiber electrode.

[0006] Three-dimensional shape changes can be facilitated by the nanofiber layers of the nanofiber electrode. One or more nanofiber layers may expand by absorbing biofluids surrounding biological tissue, such as blood. This expansion can cause the nanofiber electrode to bend, curl, or undergo any other three-dimensional shape changes. Such expansion can occur without altering the electrical and chemical properties of the nanofiber layers, and the expansion does not affect the electrical measurements and electrical stimulation performed by the nanofiber electrode, nor does it affect the insulating properties that the nanofiber layers provide to the conductive power supply. The expansion of one or more nanofiber layers, and thus the three-dimensional shape changes of the nanofiber electrode, can be further facilitated by polymer layers. Patterned polymer layers may be attached to one or more of the nanofiber layers, and the polymer layers can also absorb biofluids to further enhance the three-dimensional shape changes. Similar to the nanofiber layers, the electrical and chemical properties of the patterned polymer can remain unchanged due to the absorption of biofluids. Therefore, the nanofiber electrode is robust to the biological environment when deployed.

[0007] The nanofiber layer may be made of biocompatible and biodegradable biomass material. In some examples, biomass material such as chitin can aid in the healing of tissue surrounding the nanofiber electrode. Furthermore, carbon nanotubes or silver nanowires used to construct the power supply can be biologically harmless. Moreover, patterned polymers can also be biologically harmless. Therefore, the embodiments disclosed herein can achieve significant improvements over conventional electrodes. Figure 1 shows an exemplary biological environment 100 according to an exemplary embodiment of this disclosure. In some embodiments, the exemplary biological environment 100 may represent the human body environment and / or any other type of biological medium (e.g., animal body, tissue culture, etc.). The biological environment 100 may include nanofiber electrodes 102 placed on tissue 104. As shown in the figure, the nanofiber electrodes 102 may conform to the shape / contour of tissue 104. In some embodiments, tissue 104 may represent human tissue or animal tissue (e.g., nerve fibers, muscle fibers, etc.).

[0008] The nanofiber electrode 102 may include a plurality of electrical contacts 106a to 106i and a corresponding plurality of power supply lines 108a to 108i. The plurality of electrical contacts 106a to 106i may be configured to measure the electrical parameters of tissue 104. The plurality of power supply lines 108a to 108i may be configured to transmit the measured electrical parameters to connected electronic equipment (not shown). In some embodiments, the plurality of power supply lines 108a to 108i may be configured to transmit electrical stimuli to the corresponding plurality of electrical contacts 106a to 106i, which can then deliver the electrical stimuli to tissue 104.

[0009] The electrical contacts 106a to 106i may be exposed to contact the tissue 104, while the power supply lines 108a to 108i may be insulated from the environment by a layer of nanofibers. For example, the power supply lines 108a to 108i may be located between two layers of insulating nanofibers. In some embodiments, the nanofiber layers of the nanofiber electrode 102 may be configured to change their shape when exposed to a liquid medium (e.g., a biological fluid medium such as blood). This change in shape may allow the nanofiber electrode 102 to conform to the contour of the tissue 104. For example, as shown in the figure, the tissue 104 is cylindrical in shape and has a round cross-section. In such an example, the nanofiber electrode 102 can wrap around the tissue 104. One or more nanofiber layers of the nanofiber electrode 102 can absorb the liquid without degradation and without changes in their electrical and chemical properties. Thus, when the nanofiber electrode 102 physically changes its shape to conform to the contour of the tissue 104, the power supply lines 108a-108i remain insulated and the functionality of electrical measurement and electrical stimulation is not affected.

[0010] In some embodiments, in addition to the nanofiber layer, the nanofiber electrode 102 may also include a polymer layer (described in detail with reference to Figures 3A-3B below). The polymer layer can also absorb liquids and further alter the shape of the nanofiber electrode 102. Thus, the combination of the nanofiber layer and the polymer layer can achieve a desired level of flexibility in the nanofiber electrode 102, which can change to a desired shape during placement to conform to the contours of biological tissue. In addition to conforming to the contour of the tissue 104, the nanofiber electrode 102 can itself form a bonding function to the tissue. Since the nanofiber electrode 102 can wrap around the tissue 104, this wrapping can act as a mechanical, non-invasive anchor between the tissue 104 and the nanofiber electrode 102. Therefore, no further fixing members may be required when the nanofiber electrode 102 is placed on the tissue 104.

[0011] Figure 2A shows an exemplary method 200 for fabricating nanofiber electrodes according to an exemplary embodiment of this disclosure. Figure 2B shows the progress of the fabrication process according to an exemplary embodiment of this disclosure, following the discussed steps of method 200. This method may begin in step 202. In step 202, a nanofiber substrate 224 and a polyimide film 222 (this is merely an example, and other types of materials may be used) are prepared. In some embodiments, the nanofiber substrate 224 may represent a nanofiber paper substrate. In some embodiments, the polyimide film 222 may include a formed pattern. In some embodiments, the pattern may be formed by laser cutting a desired pattern into a blank polyimide film. The pattern formed on the polyimide film 222 can define the structure of the power supply path in the fabricated nanofiber electrode. That is, the pattern can form openings for a conductive material 226 (as described below) to spread on the nanofiber substrate to take on the shape and size defined by the pattern.

[0012] In step 204, a power supply path may be formed. In some embodiments, the power supply path may be formed using substeps 205, 206, and 208. In substep 205, the conductive material 226 may be deposited on a combination of a polyimide film 222 and a nanofiber substrate 224. As shown above, the polyimide film 222 includes a formed pattern. Once deposited, the conductive material 226 can form a power supply path at the openings in the patterned polyimide film 222. In some embodiments, to obtain such functionality, the conductive material 226 may have a desired viscosity so that it can spread on the nanofiber substrate 224 within the laser-cut structure of the patterned polyimide film 222. In some embodiments, the conductive material 226 may include a nanowire suspension. In some embodiments, the conductive material 226 may include a carbon nanotube suspension.

[0013] In substep 206, the conductive material 226 may be spread on the nanofiber substrate 224 in a laser-cut pattern of the patterned polyimide film 222. In some embodiments, the spreading may include a filtration process, where a solution containing a nanowire suspension or carbon nanotube suspension, e.g., a solute (nanowire, carbon nanotube), acts as a solvent, and the nanofiber substrate 224 can act as a film for the solute to spread on the film. In some embodiments, the conductive material 226 may be spread mechanically, for example, by using a spreading arm.

[0014] In substep 208, the patterned polyimide film 222 may be peeled off from the nanofiber substrate 224. In some embodiments, the patterned polyimide film 222 is peeled off after the conductive material 226 and the nanofiber substrate 224 have dried. That is, the patterned polyimide film 222, which provided a structure for the conductive material 226 to spread, is no longer needed after the conductive material 226 has spread to the desired shape and size and has dried.

[0015] In step 210, the mask 228 may be applied to the edge of the conductive material 226. When depositing non-conductive nanofibers (such as a passivation layer), the mask 228 can form a barrier layer on the corresponding edge of the conductive material 226. In some embodiments, the mask 228 may be formed from polydimethylsiloxane (PDMS). In step 212, the nanofibers 227 may be deposited on the conductive material 226. The nanofibers 227 may form a passivation layer (e.g., for non-conductivity protection) on the conductive material 226. In some embodiments, the nanofibers 227 may have similar physical and / or chemical properties to the nanofiber substrate 224. In some embodiments, the nanofibers 227 and the nanofiber substrate 224 may have different physical and / or chemical properties. In step 214, the nanofibers 227 may be spread over the conductive material 226. In some embodiments, the nanofibers 227 may be present in a suspension, and the spreading may be by filtration. During filtration, the nanofibers 227 may act as solutes, and the conductive material 226 may act as a membrane for the solutes to spread. However, the masked portion of the conductive material 226 may not be reached by the spread of the nanofibers 227. In some embodiments, the nanofibers 227 may be mechanically spread, for example, by using a spreading arm. After spreading the nanofibers 227, the conductive material 226 other than the masked portion is located between the nanofiber substrate 224, which is one of the two layers of nanofibers, and the layer formed by the nanofibers 227. Each of the nanofiber substrate 224 and the nanofibers 227 may change its shape when exposed to a liquid medium.

[0016] In step 216, the mask 228 (for example, a PDMS mask) may be removed to expose the electrical contact 230. In step 218, the nanofiber substrate 224 and the nanofibers 227 can be cut into a desired shape to obtain a nanofiber electrode 232 having two power supply paths 234a, 234b formed by the conductive material 226. A part of the conductive material 226 is exposed to form the electrical contact 230 of the nanofiber electrode 232. Here, the nanofiber electrode 232 can be in a state ready to be placed on human tissue.

[0017] In some embodiments, the length of each of the power supply paths 234a, 234b of the nanofiber electrode 232 filaments may be approximately 1 mm, the distance between the power supply paths 234a, 234b may be approximately 300 μm, and the width of the power supply paths 234a, 234b at the thin end may be approximately 200 μm. The thickness of each of the upper nanofiber layer and the lower nanofiber layer (for example, formed by the nanofiber substrate 224) may be approximately 5 μm, while the thickness of each of the power supply paths 234a, 234b may be approximately 2.46 ± 0.135 μm. Figure 3A shows an exemplary method 300 for generating a nanofiber substrate, such as a nanofiber substrate 224, which will be used in a nanofiber electrode, according to an exemplary embodiment of this disclosure. Figure 3B shows the progress of the generation of the nanofiber substrate through the discussed steps of method 300, according to an exemplary embodiment of this disclosure. Method 300 may begin in step 302. In step 302, the acrylamide monomer 308 may be set on a nanofiber mat 310. The nanofiber mat 310 may be made of a biomass material such as chitin or chitosan. The assembly of the acrylamide monomer 308 and the nanofiber mat 310 may be carried out on an inert, non-reactive substrate 312.

[0018] In step 304, the acrylamide monomer 308 may be polymerized. In some embodiments, polymerization may be carried out using ultraviolet light. Polymerization can form a bilayer of polyacrylamide 314 and nanofiber mat 310. In step 306, ablation may be used to create a pattern in the bilayer structure of polyacrylamide 314 and nanofiber mat 310. In some embodiments, the ablation may include laser ablation. It should be understood that laser ablation does not alter the insulating properties of the bilayer structure of polyacrylamide 314 and nanofiber mat 310. That is, even if the pattern contains gaps, the bilayer can still accept and hold conductive material and can insulate conductive material when the bilayer is exposed to a liquid medium.

[0019] Figure 4 shows the shape change properties of a nanofiber layer produced using the method 300 shown in Figures 3A-3B, according to an exemplary embodiment of this disclosure. As shown in the figure, patterning can allow the polyacrylamide 314 to expand in a liquid medium without compromising the structural integrity of the overall structure. For example, planar polyacrylamide 314 and nanofiber mat 310 can form a planar structure 420, which can bend to form a cylindrical structure 422 (having a round cross-section) when exposed to a liquid medium. Upon drying, the bilayer can return to its original planar structure 420. The change in shape between the planar structure 420 and the annular structure 422 can be without chemical changes to the polyacrylamide 314 and nanofiber mat 310. Therefore, given that it is bent when inserted into a liquid medium and returns to an unbent shape when not in a liquid medium, the bilayer structure can be a self-bending device. This self-bending property can allow nanofiber electrodes to conform to the contours of biological tissues. The bent structure can further function as a mechanical anchor between the nanofiber electrode and the biological tissue. For example, one or more nanofiber layers of the nanofiber electrode 102 shown in Figure 1 may be formed using this double-layer structure.

[0020] Figure 5A shows an exemplary method 500 for producing a nanofiber substrate (e.g., nanofiber substrate 224) from a biomass material, according to an exemplary embodiment of this disclosure. Figure 5B shows the progress of nanofiber substrate production in a factory setting using the discussed steps of method 500, according to an exemplary embodiment of this disclosure. As shown in the figure, the final constructed nanofiber substrate may be in the form of paper. Method 500 may begin in step 502, in which a biomass raw material 512 extracted from a biological material 510 such as cellulose, chitin, chitosan, and / or silk fibroin is supplied to an extraction chamber and pressurized by one or more intensifiers. In particular, there may be two intensifiers 514a and 514b capable of producing two pressurized slurry flows of the biomass material 512 (e.g., containing biomass slurry and water). In some embodiments, one or more of the two intensifiers 514a and 514b can pressurize the slurry flow to a relatively high pressure of 245 MPa (megapascals).

[0021] In step 504, two pressurized slurry flows may be collided. For example, a collider 518 may be used to collide the pressurized slurry flows at an oblique angle, and the pressurization and collision may generate nanofibers derived from the biomass material 512. In some embodiments, the pressurization and collision steps are sometimes collectively referred to as water jetting. In step 506, the nanofibers may be discharged through the cooler 520. The cooler 520 can reduce the high temperature that occurs during the pressurization and impaction steps. In step 508, the cooled nanofibers may be filtered by passing them through various membranes 522. After filtration, a nanofiber paper substrate 524 can be obtained. The nanofiber paper substrate 524 may be used to fabricate nanofiber electrodes. For example, the nanofiber paper substrate 524 may be used as the nanofiber substrate 224 in method 200 and as the nanofiber mat 310 in method 300. The nanofiber paper substrate 524 can form the insulating portion of the nanofiber electrode.

[0022] Method 500 can be used to produce nanofiber substrates of any kind of biomass material. Some non-limiting examples may include cellulose-based nanofiber substrates, chitosan-based nanofiber substrates, chitin-based nanofiber substrates, and silk fibroin-based nanofiber substrates. In some embodiments, each nanofiber substrate may have a thickness of approximately 5 μm. In some embodiments, the light transmittance of the nanofiber substrates may be as follows: Chitin-based nanofiber substrates may be more transparent than chitosan-based nanofiber substrates; chitosan-based nanofiber substrates may be more transparent than chitin-based nanofiber substrates; and chitin-based nanofiber substrates may be more transparent than silk fibroin-based nanofiber substrates.

[0023] Figure 6 shows an exemplary biomass material for constructing a nanofiber substrate for a nanofiber electrode according to an exemplary embodiment of this disclosure. The biomass material may be used by a method 500 for producing a nanofiber paper substrate 524. As shown in the figure, crab shells 602 may be used as the biomass material. The crab shells 602 may have a hierarchical structure 604 formed by a complex 606 of chitin nanofibers and proteins. Multiple strands 608 may be present within the complex 606 of chitin nanofibers and proteins. The strands 608 may have multiple nanofibers 610. Thus, the nanofibers 610 can be extracted from the crab shells 602 by one or more processes 612 such as deproteinization, demineralization, delipidization, decolorization, and / or any other type of process. An example process for extracting nanofibers 610 may be water jetting, which involves applying high-pressure water to the biomass. Figure 7 illustrates exemplary transitions between wet and dry carbon nanotube electrodes according to an exemplary embodiment of this disclosure. For example, a dry electrode 702 and a wet electrode 704 are shown. As can be seen from the figure, the shape of the dry electrode 702 changed when placed in a liquid medium (e.g., inside the human body).

[0024] Figure 8 shows another exemplary transition between wet and dry silver nanowire electrodes according to an exemplary embodiment of this disclosure. For example, dry electrode 802 and wet electrode 804 are shown. As can be seen from the figure, the shape of dry electrode 802 changed when placed in a liquid medium (e.g., inside the human body). Figure 9 shows an exemplary method 900 using a nanofiber electrode according to an exemplary embodiment of this disclosure. Method 900 may be used to electrically stimulate tissue and / or to perform electrical measurements of tissue. In step 902, the nanofiber electrode may be placed in tissue. In some embodiments, the tissue may have a substantially rounded contour. For example, blood vessels and nerves can generally be cylindrical with substantially rounded cross-sections. As discussed throughout this disclosure, the nanofiber electrode may have a first nanofiber layer, a second nanofiber layer, and one or more conductive power supply paths located between the first and second nanofiber layers.

[0025] In step 904, the nanofiber electrode may be exposed to biological fluids (e.g., blood) near the tissue, causing the nanofiber electrode to change its three-dimensional shape. This shape change may be caused by at least one of the first or second nanofiber layers absorbing the biological fluid and subsequently expanding. Further examples of embodiments of the methods and devices described herein are proposed in accordance with the structures and techniques described herein. Other non-limiting examples may be configured to be performed separately, or incorporated into any substitution or combination with any one or more of the other examples shown above or throughout this disclosure. Those skilled in the art will recognize that this disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of this disclosure. Therefore, the embodiments disclosed herein are considered illustrative and unrestricted in all respects. The scope of the disclosure is indicated not by the foregoing description but rather by the appended claims, and any modifications and equivalents that fall within the intent and scope are intended to be encompassed within the scope of the disclosure.

[0026] The steps of the methods discussed herein are presented merely as examples and should not be considered limiting. Alternative, additional, or fewer steps of a method should be considered within the scope of this disclosure. Furthermore, the steps are numbered merely for identification purposes, and the numbering is not intended to imply limitation to any individual step shown or to any set of steps shown. It should be noted that the terms “including” and “comprising” should be interpreted as “including but not limited to.” Unless explicitly stated in the claims, the term “one (a)” should be interpreted as “at least one,” and “the,” “the said,” etc., should be interpreted as “at least one,” “the said at least one,” etc. Furthermore, it is the applicant’s intention that only claims containing the expression “means for” or “steps for” should be interpreted under 35 U.SC 112(f). Claims that do not explicitly contain the phrase “means for” or “steps for” should not be interpreted under 35 U.SC 112(f).

Claims

1. First nanofiber layer, Second nanofiber layer, One or more conductive power supply circuits located between a first nanofiber layer and a second nanofiber layer, wherein the first nanofiber layer and the second nanofiber layer are configured to insulate the one or more conductive power supply circuits, and One or more electrical contacts attached to one or more conductive power supply circuits, configured to contact tissue and measure the electrical parameters of the tissue. A nanofiber electrode comprising, A nanofiber electrode in which at least one of the first nanofiber layer or the second nanofiber layer is configured to absorb a liquid and expand when exposed to a liquid, thereby changing the three-dimensional shape of the nanofiber electrode.

2. The nanofiber electrode according to claim 1, wherein at least one of the first nanofiber layer or the second nanofiber layer is formed of a biomass material.

3. The nanofiber electrode according to claim 2, wherein the biomass material comprises at least one of chitin, chitosan, or silk fibroin.

4. The nanofiber electrode according to claim 1, wherein one or more conductive power supply circuits are formed of carbon nanotubes.

5. The nanofiber electrode according to claim 1, wherein one or more conductive power supply circuits are formed by silver nanowires.

6. The nanofiber electrode according to claim 1, wherein at least one of the first nanofiber layer and the second nanofiber layer includes a polymer layer having a pattern configured to promote a change in the three-dimensional shape of the nanofiber electrode.

7. The nanofiber electrode according to claim 6, wherein the polymer layer is formed of polyacrylamide.

8. The nanofiber electrode according to claim 1, wherein the nanofiber electrode is configured to be substantially planar when dry, and to be substantially annular in at least a portion when exposed to a liquid.

9. A method for fabricating nanofiber electrodes, The steps include: forming one or more conductive power supply paths in a first nanofiber layer using a patterned film, wherein the patterned film defines the shape of one or more conductive power supply paths; The steps include: covering at least a portion of one or more conductive power supply circuits with a second nanofiber layer such that at least a portion of one or more conductive power supply circuits is located between a first nanofiber layer and a second nanofiber layer, wherein the first nanofiber layer and the second nanofiber layer are configured to insulate one or more conductive power supply circuits; The step of forming one or more electrical contacts attached to one or more conductive power supply circuits, wherein one or more electrical contacts are configured to contact tissue and measure the electrical parameters of the tissue. and A method comprising configuring at least one of a first nanofiber layer or a second nanofiber layer to absorb a liquid and expand upon exposure to the liquid, thereby changing the three-dimensional shape of the nanofiber electrode.

10. The method according to claim 9, wherein at least one of the first nanofiber layer and the second nanofiber layer is formed of a biomass material.

11. The method according to claim 10, wherein the biomass material comprises at least one of chitin, chitosan, or silk fibroin.

12. The method according to claim 9, wherein one or more conductive power supply circuits are formed of carbon nanotubes.

13. The method according to claim 9, wherein one or more conductive power supply circuits are formed by silver nanowires.

14. The method according to claim 9, wherein at least one of the first nanofiber layer and the second nanofiber layer includes a polymer layer having a pattern configured to promote a change in the three-dimensional shape of the nanofiber electrode.

15. The method according to claim 14, wherein the polymer layer is formed of polyacrylamide.

16. A nanofiber electrode for use in a method, The method is The steps include: placing a nanofiber electrode in tissue, wherein the nanofiber electrode comprises a first nanofiber layer, a second nanofiber layer, one or more conductive power supply circuits located between the first and second nanofiber layers, the first and second nanofiber layers insulating one or more conductive power supply circuits, and one or more electrical contacts attached to one or more conductive power supply circuits, having one or more electrical contacts that contact the tissue to measure the electrical parameters of the tissue; The steps include exposing a nanofiber electrode to biological fluid near the tissue, causing at least one of the first or second nanofiber layers to absorb the biological fluid and expand, thereby changing the three-dimensional shape of the nanofiber electrode, and ensuring that the changed three-dimensional shape conforms to the contour of the tissue. Nanofiber electrodes, including

17. The nanofiber electrode according to claim 16, wherein the contour of the tissue is substantially annular, and the altered three-dimensional shape is substantially annular.

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