Collagen implants remain supple not allowing fibroblast ingrowth

Dense, reconstituted collagen membranes, using an optimized cross-linking protocol, were implanted subcutaneously into rats. After implantation, only a mild inflammatory response in the surrounding tissues was observed. The morphology of the fibroblasts around the membranes was seen to go through characteristic stages of proliferation and synthesis. In the 7 week follow-up it was found that these membranes did not allow any fibroblast ingrowth into their substance and remained completely intact and supple without signs of calcification, whereas the non-cross-linked controls proved to be completely degraded. The cross-linked reconstituted collagen may thus be considered for use in situations where neither incorporation nor dissolution of the biomaterial is desired.