# US 11,109,955 B2 · Dermal layer for grafting having improved graft survival rate and method for producing same

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- Number: US 11,109,955 B2
- Document ID: US11109955B2
- Status: Granted
- Kind: B2
- Application number: 16/331,226
- Filed: 2017-03-22
- Published: 2019-09-12
- Granted: 2021-09-07
- Earliest claimed: 2016-09-07
- Assignees: Pharmaresearch Co., Ltd.
- Applicants: Pharmaresearch Products Co., Ltd.
- Inventors: Ik Soo Kim; Han Gyu Kim; Su Yeon Lee
- Web page: https://patentgrep.com/patent/US11109955B2

## CPC

- A61F 2/105: {Skin implants, e.g. artificial skin}
- A61F 2/10: Hair or skin implants
- A61L 27/20: Polysaccharides
- A61L 27/36: containing ingredients of undetermined constitution or reaction products thereof {, e.g. transplant tissue, natural bone, extracellular matrix (isolated natural compounds, e.g. collagen A61L27/24)}
- A61L 27/3633: {Extracellular matrix [ECM]}
- A61L 27/60: Materials for use in artificial skin
- A61L 27/362: {Skin, e.g. dermal papillae}
- A61L 2300/258: Genetic materials, DNA, RNA, genes, vectors, e.g. plasmids
- A61L 2430/34: for soft tissue reconstruction
- A61L 2430/40: Preparation and treatment of biological tissue for implantation, e.g. decellularisation, cross-linking
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- 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)

## Abstract

The present invention relates to a dermal layer which is for grafting and has an improved graft survival rate, and a method for producing the same, wherein the dermal layer for grafting can be produced by filling a filling solution, including a DNA fragment mixture and chitosan, into an acellular dermal matrix from which cells have been removed. It was observed that the dermal layer for grafting produced in this manner, due to the filling solution filled therein and including a DNA fragment mixture and chitosan, increases the rate at which cells flow in from the tissue surrounding the graft and are fixed, and thereby alleviates an initial inflammatory reaction and promotes blending with the surrounding tissue.

## Claims

### Claim 1

A method for producing a dermal layer for grafting, the method comprising:
a) preparing a stock solution containing a DNA fragment mixture, wherein the DNA fragment mixture is from fish testis or sperm;
b) preparing a chitosan stock solution;
c) mixing the DNA fragment mixture stock solution and the chitosan stock solution in a weight ratio of 20:1-10,000:1 of the DNA fragment mixture to chitosan;
d) stirring the resulting mixture of the DNA fragment mixture stock solution and the chitosan stock solution;
e) sterilizing the mixture of the DNA fragment mixture stock solution and the chitosan stock solution to obtain a loading solution; and
f) loading the loading solution to an acellular dermal matrix to obtain the dermal layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein
in step a, the DNA fragment mixture is dissolved in a buffer at 50° C. to 70° C. for 1 to 3 hours to produce the DNA fragment mixture stock solution;
in step b, chitosan is dissolved in an acidic buffer to produce the chitosan stock solution;
in step d the DNA fragment mixture stock solution and the chitosan stock solution are stirred at 65° C. to 75° C. for 1 to 2 hours; and
in step f, the loading solution is loaded to the acellular dermal matrix by means of a vacuum drug loading device.

### Claim 3 (depends on 1)

The method of claim 1, wherein the fish is of the family Salmonidae.

### Claim 4 (depends on 1)

The method of claim 1, wherein the DNA fragment mixture has a molecular weight of 50 kDa to 10,000 kDa.

### Claim 5 (depends on 1)

The method of claim 1, wherein the DNA fragment mixture is used in an amount of 0.01% by weight to 3% by weight, based on the total weight of the loading solution.

### Claim 6 (depends on 1)

The method of claim 1, wherein the chitosan has a molecular weight of 3 kDa to 1,000 kDa.

### Claim 7 (depends on 1)

The method of claim 1, wherein the chitosan is used in an amount of 1×10−6% by weight to 0.15% by weight, based on the total weight of the loading solution.

### Claim 8 (depends on 1)

The method of claim 1, wherein the acellular dermal matrix in step f is a biologically inactivated collagen-based tissue supplement material that has been obtained by removing cells and impurities from a dermal matrix and subjecting the dermal matrix to virus inactivation and then to lyophilization.

### Claim 9 (depends on 8)

The method of claim 8, wherein the dermal matrix is an autograft, allograft, or heterograft.

### Claim 10 (depends on 1)

The method of claim 1, wherein the loading in step f is carried out by introducing the viscous loading solution into the acellular dermal matrix by means of a pressure to fill empty spaces between collagens.

### Claim 11 (depends on 2)

The method of claim 2, wherein the loading solution is loaded into the vacuum drug loading device and the acellular dermal matrix is affixed thereto and wherein the vacuum drug loading device generates a positive or negative pressure to infiltrate the loading solution into empty spaces inside the acellular dermal matrix.

### Claim 12 (depends on 2)

The method of claim 2, wherein the chitosan has a molecular weight of 3 kDa to 1,000 kDa.

### Claim 13 (depends on 2)

The method of claim 2, wherein the DNA fragment mixture has a molecular weight of 50 kDa to 10,000 kDa.

### Claim 14 (depends on 2)

The method of claim 2, wherein the DNA fragment mixture is used in an amount of 0.01% by weight to 3% by weight, based on the total weight of the loading solution.

### Claim 15 (depends on 2)

The method of claim 2, wherein the chitosan is used in an amount of 1×10−6% by weight to 0.15% by weight, based on the total weight of the loading solution.