Tissue grafts modified with a cross-linking agent and method of making and using the same

Abstract

Described herein are tissue grafts derived from the placenta that possess good adhesion to biological tissues and are useful in would healing applications. In one aspect, the tissue graft includes (1) two or more layers of amnion, wherein at least one layer of amnion is cross-linked, (2) two or more layers of chorion, wherein at least one layer of amnion is cross-linked, or (3) one or more layers of amnion and chorion, wherein at least one layer of amnion and/or chorion is cross-linked. In another aspect, the grafts are composed of amnion and chorion cross-linked with one another. In a further aspect, the grafts have one or more layers sandwiched between the amnion and chorion membranes. The amnion and/or the chorion are treated with a cross-linking agent prior to the formation of the graft. Also described herein are methods for making and using the tissue grafts.

1 . A tissue graft comprising (1) two or more layers of amnion, wherein at least one layer of amnion is cross-linked, (2) two or more layers of chorion, wherein at least one layer of chorion is cross-linked, or (3) one or more layers of amnion and chorion, wherein at least one layer of amnion and/or chorion is cross-linked. 
     
     
         2 . The tissue graft of  claim 1  produced by the process comprising:
 a. providing a first amnion having a first surface and a second surface; and 
 b. laminating a second amnion or chorion having a first surface and a second surface to the second surface of the first amnion, where the first surface of the second amnion or chorion is laminated to the second surface of the first amnion, and wherein the first amnion, second amnion, and/or the chorion are treated with a cross-linking agent prior to lamination. 
 
     
     
         3 . The tissue graft of  claim 1  produced by the process comprising:
 c. providing a first chorion having a first surface and a second surface; and 
 d. laminating a second chorion having a first surface and a second surface to the second surface of the first chorion, where the first surface of the second chorion is laminated to the second surface of the first chorion, and wherein the first chorion and/or second chorion are treated with a cross-linking agent prior to lamination. 
 
     
     
         4 . The tissue graft of  claim 1  produced by the process comprising:
 a. providing a first amnion having a first surface and a second surface; and 
 b. laminating a second amnion or first chorion having a first surface and a second surface to the second surface of the first amnion, where the first surface of the second amnion or first chorion is laminated to the second surface of the first amnion to produce a laminated article; and 
 c. contacting the laminated article with a cross-linking agent. 
 
     
     
         5 . The tissue graft of  claim 1  produced by the process comprising:
 a. providing a first chorion having a first surface and a second surface; and 
 b. laminating a second chorion or first amnion having a first surface and a second surface to the second surface of the first chorion, where the first surface of the second chorion or first amnion is laminated to the second surface of the first chorion to produce a laminated article, and 
 c. contacting the laminated article with a cross-linking agent. 
 
     
     
         6 . The graft of  claim 1 , wherein the amnion and the chorion are treated with the same cross-linking agent. 
     
     
         7 . The graft of  claim 1 , wherein the amnion and the chorion are treated with different cross-linking agents. 
     
     
         8 . The graft of  claim 1 , wherein the first surface of the amnion comprises an exposed basement layer or an unexposed basement layer. 
     
     
         9 . The graft of  claim 1 , wherein the cross-linking agent comprises a sugar. 
     
     
         10 . The graft of  claim 9 , wherein the sugar comprises D-ribose, glycerose, altrose, talose, ertheose, glucose, lyxose, mannose, xylose, gulose, arabinose, idose, allose, galactose, maltose, lactose, sucrose, cellibiose, gentibiose, melibiose, turanose, trehalose, isomaltose, or any combination thereof. 
     
     
         11 . The graft of  claim 1 , wherein the cross-linking agent comprises a dialdehyde, a carbodiimide, or a combination thereof. 
     
     
         12 . The graft of  claim 1 , wherein the amnion comprises a fibroblast cell layer. 
     
     
         13 . The graft of  claim 1 , wherein the amnion and/or chorion is treated with 0.1 M to 5.0 M D-ribose for 0 to 60 minutes. 
     
     
         14 . The graft of  claim 1 , wherein the tissue graft is produced by the method comprising
 a. optionally removing substantially all of the epithelium cells of the amnion to expose the basement membrane of the amnion to produce a first membrane having an exposed basement membrane and a second surface;   b. treating the first membrane with a first cross-linking agent; and   c. mounting a chorion membrane having a stromal layer and a second surface to the amnion, wherein the stromal layer of the chorion is adjacent to the second surface of the amnion, wherein the chorion is treated with a second cross-linking agent, and wherein the first cross-linking agent and the second cross-linking agent are the same or different.   
     
     
         15 . The graft of  claim 1 , wherein the graft is produced by the method comprising:
 a. obtaining a placenta from a subject;   b. cleaning the placenta;   c. separating the chorion tissue layer from the amnion, wherein the amnion comprises epithelium cells adjacent to a basement membrane;   d. optionally removing substantially all of the epithelium cells to expose the basement membrane of the amnion to produce a first membrane;   e. treating the first membrane and chorion with one or more cross-linking agents;   f. mounting the first membrane onto a surface of a drying fixture, wherein the basement membrane of the first membrane is adjacent to the surface of the drying fixture;   g. mounting chorion on the first membrane to produce the tissue graft; and   h. dehydrating the tissue graft on the drying fixture.   
     
     
         16 . The graft of  claim 15 , wherein when the epithelium cells are substantially removed, step (d) comprises mechanical or chemical removal of the epithelium layer to substantially remove the epithelium layer. 
     
     
         17 . The graft of  claim 15 , wherein the dehydrating step (h) comprises heating the tissue graft or chemically dehydrating/freeze-drying the tissue graft. 
     
     
         18 . The graft of  claim 15 , wherein the dehydrating step (h) comprises placing the drying fixture with the layered tissue graft mounted to the fixture in a breathable bag and heating the bag in an oven or incubator chamber, wherein the oven or incubator chamber is heated at a temperature of between 35° C. and 50° C. between 30 minutes to several days. 
     
     
         19 . The graft of  claim 15 , wherein the surface of the drying fixture has a plurality of grooves that defines the outer contours of each of the plurality of placenta. 
     
     
         20 . The graft of  claim 15 , wherein the drying fixture includes a texture or design adapted to emboss such texture or design into the basement membrane during dehydration. 
     
     
         21 . The graft of  claim 1 , wherein one or more additional membranes are laminated to the second surface of the amnion membrane, wherein one or more additional membranes are treated with a cross-linking agent. 
     
     
         22 . The graft of  claim 21 , wherein the one or more additional membranes comprises amnion, chorion, allograft pericardium, allograft acelluar dermis, amniotic membrane, Wharton's jelly, purified xenograft Type-1 collagen, biocellulose polymers or copolymers, biocompatible synthetic polymer or copolymer films, purified small intestinal submucosa, bladder acellular matrix, cadaveric fasia, or any combination thereof. 
     
     
         23 . The graft of  claim 21 , wherein the one or more additional membranes comprise an amnion membrane comprising a fibroblast cell layer, wherein one or more amnion membranes are optionally treated with a cross-linking agent. 
     
     
         24 . A tissue graft comprising amnion and chorion membrane, wherein the amnion and chorion are covalently attached to one another via a cross-linker, and wherein the amnion comprises a fibroblast cell layer. 
     
     
         25 . A wound dressing comprising the tissue graft of  claim 1 . 
     
     
         26 . An amnion membrane or a chorion membrane comprising at least one cross-linker covalently attached to the membrane. 
     
     
         27 . A method for preventing or reducing scar formation on or near the spine after a surgical procedure, or for treating a dural tear, or for promoting the healing of a wound, the method comprising applying to a subject a tissue graft of  claim 1  directly to the spinal dura of the subject or a region near the spine, or to the dural tear, or to the wound. 
     
     
         28 .- 53 . (canceled)