# US 2024/0198091 A1 · Highly microporous graphene-based neural electrode

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- Number: US 2024/0198091 A1
- Document ID: US20240198091A1
- Status: Published application
- Kind: A1
- Application number: 18/532,214
- Filed: 2023-12-07
- Published: 2024-06-20
- Earliest claimed: 2022-12-07
- Applicants: George Mason University
- Inventors: Pilgyu Kang; Shirin Movaghgharnezhad
- Web page: https://patentgrep.com/patent/US20240198091A1

## CPC

- A61N 1/0551: {Spinal or peripheral nerve electrodes}
- A61B 5/268: containing conductive polymers, e.g. PEDOT:PSS polymers
- A61B 5/294: for nerve conduction study [NCS]
- A61B 5/6877: {Nerve}
- A61N 1/0456: {Specially adapted for transcutaneous electrical nerve stimulation [TENS]}
- A61N 1/36125: {Details of circuitry or electric components}
- C01B 32/184: Preparation
- C01B 2204/22: Electronic properties
- C01B 2204/32: Size or surface area
- C01P 2004/03: obtained by SEM
- C01P 2006/12: Surface area
- C01P 2006/14: Pore volume
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

Highly microporous laser fabricated three-dimensional graphene which can be prepared from a fluorinated polyimide is disclosed as a material suitable for a neural electrode, e.g., a neural stimulation device. The three-dimensional porous graphene incorporated into the device may have a multi-scale structure, which enables electrical and charge carrying properties. In some aspects, the porous graphene incorporated into the device has the following pore structure: macropores having an average pore size exceeding 50 nm; mesopores having an average pore size of 2-50 nm; micropores having an average pore size of 2 nm or less; and nanopores having an average pore size of less than 100 nm. Neural stimulation devices and methods of using the devices are also described.

## Claims

### Claim 1

A neural stimulation device, comprising:
a) a substrate;
b) a transparent polymer film deposited on the substrate; and
c) at least one layer of porous graphene on or within the transparent polymer film;
wherein the at least one layer of porous graphene has the following pore structure:
i) macropores having an average pore size exceeding 50 nm;
ii) mesopores having an average pore size of 2-50 nm;
iii) micropores having an average pore size of 2 nm or less; and
iv) nanopores having an average pore size of less than 100 nm;
wherein the nanopores have a BET specific surface area of at least 300 m2/g.

### Claim 2 (depends on 1)

The neural stimulation device of claim 1, wherein the nanopores have a BET specific surface area of 300-1500 m2/g.

### Claim 3 (depends on 1)

The neural stimulation device of claim 1, wherein the at least one layer of porous graphene exhibits a Horvath-Kawazoe pore volume of at least 0.2 cm3/g.

### Claim 4 (depends on 1)

The neural stimulation device of claim 1, wherein the at least one layer of porous graphene exhibits a Horvath-Kawazoe pore volume of 0.2-0.8 cm3/g.

### Claim 5 (depends on 1)

The neural stimulation device of claim 1, wherein the at least one layer of porous graphene has a mean graphene interlayer spacing of 0.35-0.45 nm.

### Claim 6 (depends on 1)

The neural stimulation device of claim 1, wherein the transparent polymer film comprises a fluorinated polyimide having at least one aromatic ring.

### Claim 7 (depends on 6)

The neural stimulation device of claim 6, wherein the at least one layer of porous graphene is prepared by graphitizing the fluorinated polyimide.

### Claim 8 (depends on 7)

The neural stimulation device of claim 7, wherein graphitizing comprises irradiating the film with an infrared laser.

### Claim 9 (depends on 6)

The neural stimulation device of claim 6, wherein the fluorinated polyimide has one of the following repeating units:
where each instance of n is independently an integer that is at least two.

### Claim 10 (depends on 6)

The neural stimulation device of claim 6, wherein the fluorinated polyimide is prepared by thermal imidization of a precursor polyamic acid film.

### Claim 11 (depends on 1)

The neural stimulation device of claim 1, wherein the transparent polymer film has an average thickness of 20-300 μm.

### Claim 12

A method for stimulating a nerve of a subject, comprising placing a neural stimulation device within sufficient proximity to the nerve to thereby stimulate the nerve; wherein the neural stimulation device comprises:
a) a substrate;
b) a transparent polymer film deposited on the substrate; and
c) at least one layer of porous graphene on or within the transparent polymer film;
wherein the at least one layer of porous graphene has the following pore structure:
v) macropores having an average pore size exceeding 50 nm;
vi) mesopores having an average pore size of 2-50 nm;
vii) micropores having an average pore size of 2 nm or less; and
viii) nanopores having an average pore size of less than 100 nm;
wherein the nanopores have a BET specific surface area of at least 300 m2/g.

### Claim 13 (depends on 12)

The method of claim 12, wherein the neural stimulation device contacts the nerve.

### Claim 14

A method for making a neural stimulation device, comprising:
a) depositing a transparent polymer film onto a substrate, wherein the transparent polymer film comprises a fluorinated polyimide having at least one aromatic ring; and
b) graphitizing the fluorinated polyimide to form at least one layer of porous graphene on or within the transparent polymer film.

### Claim 15 (depends on 14)

The method of claim 14, wherein the at least one layer of porous graphene has the following pore structure:
a) macropores having an average pore size exceeding 50 nm;
b) mesopores having an average pore size of 2-50 nm;
c) micropores having an average pore size of 2 nm or less; and
d) nanopores having an average pore size of less than 100 nm;
wherein the nanopores have a BET specific surface area of at least 300 m2/g.

### Claim 16 (depends on 14)

The method of claim 14, wherein the fluorinated polyimide has one of the following repeating units:
where each instance of n is independently an integer that is at least two.

### Claim 17 (depends on 14)

The method of claim 14, wherein the fluorinated polyimide is prepared by thermal imidization of a precursor polyamic acid film.

### Claim 18 (depends on 14)

The method of claim 14, wherein the transparent polymer film has an average thickness of 20-300 μm.

### Claim 19 (depends on 14)

The method of claim 14, wherein the at least one layer of porous graphene has an average thickness of 10-180 μm.

### Claim 20 (depends on 12)

The method of claim 12, wherein graphitizing comprising irradiating the fluorinated polyimide with a CO2 infrared laser having a wavelength (λ) of 10.6 μm.