Cross-linking by 1-ethyl-3- (3-dimethylaminopropyl)-carbodiimide (EDC) of a collagen/elastin membrane meant to be used as a dermal substitute: effects on physical, biochemical and biological features in vitro.

Next to in vitro-cultured autogeneic keratinocytes for the restoration of epidermis, a suitable dermal matrix is a mandatory component of an artificial skin substitute for the permanent covering of full thickness skin defects. In our model a xenogeneic membrane, consisting of processed native collagen and elastin of porcine origin is meant to serve as a template for the formation of a neo-dermis. In order to improve the resistance of this matrix against enzymatical degradation, we cross-linked it by using the carbodiimide 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) together with N-hydroxysuccinimide. Chemical cross-linking by these agents at two different degrees (shrinkage temperatures 63 degrees C and 81 degrees C) had no relevant effect on mechanical features or water-uptake capacity. The time needed for enzymatic digestion was increased by cross-linking. Concerning growth and spreading of fibroblasts and keratinocytes on and within the structure of this membrane, we did not observe a difference between cross-linked and non-cross-linked material (shrinkage temperature 48 degrees C). We therefore expect that cross-linking by EDC is an effective means to control the degradation of the collagen/elastin membranes in vivo without a significant influence on their biocompatibility.