Investigation into the biological stability of collagen/chondroitin-6-sulphate gels and their contraction by fibroblasts and keratinocytes: the effect of crosslinking agents and diamines

Artificial skin substitutes based on autologous keratinocytes cultured on c ollagen-based substrata are being developed for grafting onto patients with severe burns. The properties of the substratum can be manipulated by cross linking the collagen with the glysocaminoglycan, chondroitin-6-sulphate (Ch 6SO(4) ), carbodiimides and polyamines. Biological stability, assessed by r esistance to collagenase, was increased by incorporation of Ch6SO(4) but cr osslinking with the carbodiimides, 1-ethyl-3-(dimethylaminopropy1)carbodiim ide and 1,1-carbonyldiimidazole or the polyamines, putrescine or diaminohex ane, had little further benefit. Contraction of the collagen gels occurred to a greater extent when seeded with fibroblasts than with keratinocytes. T he extent of contraction by either cell type was not influenced by the pres ence of Ch6SO(4) in the gel, but the carbodiimides, and to a lesser extent the polyamines, limited cell-mediated contraction, particularly that mediat ed by fibroblasts. Optimum substratum composition for artificial skin subst itutes will involve a compromise between the desired attributes of biologic al stability, rate of contraction, mechanical strength, biocompatibility an d promotion of cell growth. (C) 1999 Elsevier Science Ltd. All rights reser ved.