# US 12,005,154 B2 · Nerve repair conduits incorporating silica fibers

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- Number: US 12,005,154 B2
- Document ID: US12005154B2
- Status: Granted
- Kind: B2
- Application number: 16/660,936
- Filed: 2019-10-23
- Published: 2020-04-30
- Granted: 2024-06-11
- Earliest claimed: 2018-10-26
- Assignees: American Nano, LLC
- Applicants: American Nano, LLC
- Inventors: Mitch Dellinger
- Web page: https://patentgrep.com/patent/US12005154B2

## CPC

- A61L 27/025: {Other specific inorganic materials not covered by A61L27/04 - A61L27/12}
- A61L 27/3804: {characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells}
- A61L 27/54: Biologically active materials, e.g. therapeutic substances {(A61L27/227 takes precedence)}
- C04B 35/6224: {Fibres based on silica}
- C04B 35/624: Sol-gel processing
- D01D 5/0015: {characterised by the initial state of the material}
- D01D 5/003: {the material being a polymer solution or dispersion (D01D5/0053 takes precedence)}
- D01F 9/08: of inorganic material (working or processing of metal wire B21F; from softened glass, minerals or slags C03B37/00)
- A61L 2300/252: Polypeptides, proteins, e.g. glycoproteins, lipoproteins, cytokines
- A61L 2300/414: Growth factors
- A61L 2430/32: for nerve reconstruction
- C04B 2235/5256: Two-dimensional, e.g. woven structures
- C04B 2235/526: characterised by the length of the fibers
- C04B 2235/5264: characterised by the diameter of the fibers
- D10B 2101/08: Ceramic
- D10B 2509/00: Medical; Hygiene
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES

## Abstract

Embodiments of the invention include nerve-repair conduits incorporating mats, sheets, and/or powders of silica fibers and methods for producing such conduits. The silica fibers may be formed via electrospinning of a sol gel produced with a silicon alkoxide reagent, such as tetraethyl ortho silicate, alcohol solvent, and an acid catalyst.

## Claims

### Claim 1

A method of fabricating an artificial nerve conduit, the method comprising:
electrospinning a sol-gel to form a mat of silica fibers, wherein the sol-gel is produced, at least in part, by ripening, for at least 2 days at a humidity of 40% to 80% and a temperature of 50° F. to 90° F., an initial sol comprising 70% to 90% tetraethylorthosilicate (TEOS), 8% to 25% anhydrous ethanol, an acid catalyst, and water, wherein the initial sol is free of inorganic salts; and
forming from at least a portion of the mat of silica fibers a tubular member defining a first opening configured to receive a first nerve portion and a second opening configured to receive a second nerve portion.

### Claim 2 (depends on 1)

The method of claim 1, wherein forming the tubular member comprises pressing and/or molding the silica fibers and/or a powder derived from the silica fibers.

### Claim 3 (depends on 1)

The method of claim 1, further comprising incorporating within and/or on at least a portion of the tubular member a healing agent.

### Claim 4 (depends on 3)

The method of claim 3, wherein the healing agent comprises at least one of a growth factor, a matrix protein, or a plurality of cells.

### Claim 5 (depends on 4)

The method of claim 4, wherein the healing agent comprises at least one of nerve growth factor, extracellular matrix protein, glial cell-derived neurotrophic factor, vascular endothelial growth factor, fibroblast growth factor, stem cells, blast cells, epithelial cells, or Schwann cells.

### Claim 6 (depends on 1)

The method of claim 1, wherein the initial sol is ripened for at least 3 days.

### Claim 7 (depends on 1)

The method of claim 1, wherein the sol-gel is electrospun when the weight of the sol-gel ranges from 10% to 60% of a starting weight of the initial sol prior to ripening.

### Claim 8 (depends on 1)

The method of claim 1, wherein the sol-gel is electrospun when production of ethylene vapor therefrom ranges from 10% to 40% relative to the initial sol prior to ripening.

### Claim 9 (depends on 1)

The method of claim 1, further comprising incorporating a healing agent into the sol-gel before electrospinning thereof, whereby the silica fiber mat comprises the healing agent incorporated therewithin.

### Claim 10 (depends on 1)

The method of claim 1, further comprising incorporating a healing agent onto the silica fibers during electrospinning thereof.

### Claim 11 (depends on 1)

The method of claim 1, further comprising incorporating a healing agent onto the mat of silica fibers after electrospinning thereof.

### Claim 12 (depends on 1)

The method of claim 1, wherein the initial sol consists of TEOS, anhydrous ethanol, the acid catalyst, and water.

### Claim 13

A method of fabricating an artificial nerve conduit, the method comprising:
forming from electrospun silica fibers a tubular member defining a first opening configured to receive a first nerve portion and a second opening configured to receive a second nerve portion,
wherein forming the tubular member comprises (i) electrospinning a sol-gel to form a mat of silica fibers, (ii) fragmenting the mat to form silica fiber powder, and (iii) pressing or molding at least a portion of the silica fiber powder.

### Claim 14 (depends on 13)

The method of claim 13, wherein the fibers of the mat of silica fibers have diameters ranging from approximately 50 nm to approximately 5 μm.

### Claim 15 (depends on 13)

The method of claim 13, wherein the fibers of the mat of silica fibers have diameters ranging from approximately 200 nm to approximately 1000 nm.

### Claim 16 (depends on 13)

The method of claim 13, wherein the sol-gel is produced, at least in part, by ripening an initial sol comprising 70% to 90% tetraethylorthosilicate (TEOS), 8% to 25% anhydrous ethanol, an acid catalyst, and water.

### Claim 17 (depends on 13)

The method of claim 13, further comprising incorporating a healing agent into the sol-gel before electrospinning thereof, whereby the silica fiber mat comprises the healing agent incorporated therewithin.

### Claim 18 (depends on 13)

The method of claim 13, further comprising incorporating a healing agent onto the silica fibers during electrospinning thereof.

### Claim 19 (depends on 13)

The method of claim 13, further comprising incorporating a healing agent onto the mat of silica fibers prior to fragmentation thereof.

### Claim 20 (depends on 13)

The method of claim 13, further comprising, after fragmentation of the silica fiber mat, incorporating a healing agent onto the silica fiber powder.

### Claim 21 (depends on 13)

An artificial nerve conduit fabricated according to claim 13.

### Claim 22 (depends on 16)

The method of claim 16, wherein the initial sol is ripened for at least 2 days at a humidity of 40% to 80% and a temperature of 50° F. to 90° F.

### Claim 23 (depends on 22)

The method of claim 22, wherein the initial sol is ripened for at least 3 days.

### Claim 24 (depends on 16)

The method of claim 16, further comprising incorporating within and/or on at least a portion of the tubular member a healing agent.

### Claim 25 (depends on 24)

The method of claim 24, wherein the healing agent comprises at least one of a growth factor, a matrix protein, or a plurality of cells.

### Claim 26 (depends on 24)

The method of claim 24, wherein the healing agent comprises at least one of nerve growth factor, extracellular matrix protein, glial cell-derived neurotrophic factor, vascular endothelial growth factor, fibroblast growth factor, stem cells, blast cells, epithelial cells, or Schwann cells.

### Claim 27 (depends on 16)

The method of claim 16, wherein the initial sol is free of inorganic salts.

### Claim 28 (depends on 16)

The method of claim 16, wherein the initial sol consists of TEOS, anhydrous ethanol, the acid catalyst, and water.

### Claim 29

A method of fabricating an artificial nerve conduit, the method comprising:
forming electrospun silica fibers at least in part by (i) producing a sol-gel from an initial sol comprising 75% to 90% TEOS, 8% to 25% ethanol, an acid catalyst, and water, and (ii) electrospinning the sol-gel, wherein the initial sol is free of inorganic salts; and
forming from the electrospun silica fibers a tubular member defining a first opening configured to receive a first nerve portion and a second opening configured to receive a second nerve portion,
wherein forming the tubular member comprises pressing the electrospun silica fibers and/or a powder derived from the electrospun silica fibers.

### Claim 30 (depends on 29)

The method of claim 29, further comprising incorporating within and/or on at least a portion of the tubular member a healing agent.

### Claim 31 (depends on 30)

The method of claim 30, wherein the healing agent comprises at least one of a growth factor, a matrix protein, or a plurality of cells.

### Claim 32 (depends on 30)

The method of claim 30, wherein the healing agent comprises at least one of nerve growth factor, extracellular matrix protein, glial cell-derived neurotrophic factor, vascular endothelial growth factor, fibroblast growth factor, stem cells, blast cells, epithelial cells, or Schwann cells.

### Claim 33 (depends on 29)

The method of claim 29, wherein producing the sol-gel comprises ripening the initial sol for at least 2 days at a humidity of 40% to 80% and a temperature of 50° F. to 90° F.

### Claim 34 (depends on 29)

The method of claim 29, wherein the initial sol consists of TEOS, anhydrous ethanol, the acid catalyst, and water.