Biodegradable matrix and methods for producing same

Claim 2

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of carbodiimide and dehydrothermal cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the iunterior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 3

The collagen-based sponge-like structure of claim 1 wherein the matrix is a succinimydyl ester/carbodiimide cross linked matrix, the ester being bifunctional.

Claim 4

The collagen-based sponge-like structure of claim 2 wherein the succinimidyl ester is selected from the group consisting of N-hydroxysuccinimide, 3,3-dithio-(sulfosuccinimidyl) propionate and bis(sulfosuccinimidyl) suberate.

Claim 5

The collagent-based sponge-like structure of claim 1 wherein the carbodiimide is a cyanamide.

Claim 6

The collagen-based sponge-like structure of claim 1 wherein the carbodiimide is selected from the group consisting of cyanamide, and 1-ethyl-3-3(3-dimethylaminopropyl)-carbodiimide hydrochloride.

Claim 7

A process for the preparation of the sponge of claim 1 which comprises the steps of (a) dispersing collagen in an acid solution, at pH from about 3.0 to about 4.0; (b) freezing the dispersion at about -30° C. to about 50° C.; (c) freeze-drying the dispersion at about 0.1 millitorr and about -60° C.; (d) obtaining a collagen sponge having channels of an average pore size of from about 50 um to about 250 um; and, (e) cross-linking the collagen by two cross-linking steps selected from the group consisting of (1) contacting the collagen sponge with a cross-linking agent selected from the group consisting of a carbodiimide and a combination of a bifunctional succinimidyl active ester and a carbodiimide and; (2) subjecting the collagen sponge to elevated temperatures under vacuum.

Claim 8

The process of claim 6 wherein step (2) is performed prior to step (1).

Claim 9

The process of claim 6 wherein step (1) is performed prior to step (2).

Claim 10

The process of claim 6 wherein the acid is HCl.

Claim 11

The process of claim 6 wherein the pH is 3.3.

Claim 12

The process of claim 6 wherein the freezing temperature is -30° C. to -40° C.

Claim 13

A process for the preparation of the sponge of claim 8 which comprises the steps of (a) dispersing collagen in an acid solution at pH from about 3.0 to about 4.0; (b) mixing an acid solution containing fibronectin or hyaluronic acid at pH from about 3.0 to about 4.0 with the collagen dispersion; (c) freezing the dispersion at from about -30° C. to about -50° C.; (d) freeze-drying the dispersion at about 0.1 millitorr and about -60° C.; (e) obtaining a collagen sponge having channels and an average pore size of from about 50 um to about 250 um; and, (f) cross-linking the collagen by two cross-linking steps selected from the group consisting of (1) contacting the collagen sponge with a cross-linking agent selected from the group consisting of a carbodiimide and a combination of a bifunctional succinimidyl active ester and a carbodiimide and; (2) subjecting the collagen sponge to elevated temperatures under vacuum.

Claim 14

The process of claim 12 wherein step (2) is performed prior to step (1).

Claim 15

The process of claim 12 wherein step (1) is performed prior to step (2).

Claim 16

The process of claim 12 wherein the acid is HCl.

Claim 17

The process of claim 12 wherein the pH is 3.3.

Claim 18

The process of claim 12 wherein the freezing temperature is from about -30° C. to about -40° C.

Claim 19

A process for the preparation of the sponge of claim 8 which comprises the steps of (a) dispersing collagen in an acid solution at a pH from about 3.0 to about 4.0; (b) mixing an acid solution containing fibronectin or hyaluronic acid at pH from about 3.0 to about 4.0 with the collagen dispersion; (c) freezing the dispersion at from about -30° C. to about -50° C.; (d) freeze-drying the dispersion at about 0.1 millitorr and about -60° C.; (e) obtaining a collagen sponge having channels and an average pore size of from about 50 um to about 250 um; and, (f) cross-linking the collagen by two cross-linking steps selected from the group consisting of (1) contacting the collagen sponge with a cross-linking agent selected from the group consisting of a carbodiimide and a combination of a bifunctional succinimidyl active ester and a carbodiimide and; (2) subjecting the collagen sponge to elevated temperatures under vacuum, (g) suspending the collagen sponge in an acid solution at a pH from about 3.0 to about 4.0, and freezing at from about -30° C. to about -50° C., (h) freeze-drying the collagen sponge at about 0.1 millitorr and about -60° C.; and, (i) obtaining a cross-linked collagen sponge having channels and an average pore size of from about 50 um to about 250 um.

Claim 20

The process of claim 18 wherein the acid is HCl.

Claim 21

The process of claim 18 wherein the pH is 3.3.

Claim 22

The process of claim 18 wherein the temperature is from about -30° C. to about -40° C.

Claim 23

The process of claim 18 wherein step (1) is performed prior to step (2).

Claim 24

The process of claim 18 wherein step (2) is performed prior to step (1).

Claim 25

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three dimensional matrix of carbodiimide and dehydrothermal cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagent inside the channels and new tissue formation in the wound, and wherein the matrix is cross-linked by a succinimidyl bifunctional ester/carbodiimide or a cyanamide, the matrix includes a fibrillar structure including a connective tissue factor selected from the group consisting of hyaluronic acid and fibronectin, and the pore size is in the range of about 100±50 um.

Claim 26

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three dimensional matrix of carbodiimide and dehydrothermal cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagent inside the channels and new tissue formation in the wound, and wherein the matrix is cross-linked by a succinimidyl bifunctional ester/carbodiimide or a cyanamide, the matrix includes a fibrillar structure including a connective tissue factor selected from the group consisting of hyaluronic acid and fibronectin, and the pore size is in the range of about 100±50 um.

Claim 27

THe collagen-based sponge-like structure of claim 24 wherein the matrix is also cyanamide cross-linked.

Claim 28

The collagen-based sponge-like structure of claim 24 wherein the succinimydyl ester is selected from the group consisting of N hydroxysuccinimide, 3,3-dithio (sulfosuccinimidyl) propionate and bis (sulfosuccinimidyl) suberate.

Claim 29

A biodegradable porous collagen-based sponge-like structure especially useful for the treatment of skin wounds, which comprises a biodegradable collagen fiber network containing hyaluronic acid, fibronectin, or both, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagenbased sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 30

A biodegradable porous collagen-based sponge-like structure especially useful for the treatment of skin wounds, which comprises a biodegradable collagen fiber network containing hyaluronic acid, fibronectin, or both, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagenbased sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 31

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of dehydrothermal cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 32

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of dehydrothermal cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 33

The collagen-based sponge-like structure of claim 28 positioned in a skin wound, the channels containing fibroblasts and newly formed collagen fibrils.

Claim 34

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of carbodiimide cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 35

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of carbodiimide cross-linked collagen fibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior of the sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 36

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of bifunctional succinimidyl active ester cross-linked collagenfibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.

Claim 37

A biodegradable, porous, collagen-based sponge-like composition, especially useful for the treatment of skin wounds, which comprises a biodegradable, three-dimensional matrix of bifunctional succinimidyl active ester cross-linked collagenfibers, wherein the fibers define randomly distributed surface and interior pores which are connected by channels within the interior sponge, and the channels connect the surface of the composition with the interior of the sponge-like composition, the average pore size being from about 50 to about 250 um, which collagen-based sponge-like composition promotes the healing of wounds by fibroblast movement into the channels and pores, attachment of the collagen inside the channels and new tissue formation in the wound.