INVESTIGATION INTO CELL-GROWTH ON COLLAGEN CHONDROITIN-6-SULFATE GELS- THE EFFECT OF CROSS-LINKING AGENTS AND DIAMINES/

Artificial skin substitutes based on cultured autologous keratinocytes need to have sufficient strength and ease of handling to be utilized successfully by surgeons in the clinic. This may be achieved by crossl inking the collagen substratum on which the cells are cultured, which in this case is a collagen gel. Increased strength must be attained wi thout detrimental effect on cell growth. The influence of potential cr osslinking agents including the glycosaminoglycan, chondroitin-6-sulph ate (ChGSO(4)), the water soluble carbodiimide crosslinking agents 1-e thyl-3-(3-diaminopropyl) carbodiimide (EDAC), and 1,1-carbonyldiimidaz ole (CDl), and the polyamines putrescine, spermine and diaminohexane, on cell growth rate has been investigated. Incorporation of 20% ChGSO( 4) into collagen gels caused an approximately 16% increase in keratino cyte growth, but had no significant effect on that of dermal fibroblas ts. Pre-formed collagen gels (+/- ChGSO(4)) were treated with the carb odiimides. This crosslinking treatment markedly inhibited fibroblast g rowth (EDAC 45% inhibition, CDl 70%), without affecting that of kerati nocytes. Pre-formed collagen gels (+/- ChGSO(4) and carbodiimide) were treated with 0.1 M, 0.5 M or 1.0 M polyamine. Spermine inhibited the growth rate of both cell types at all concentrations tested, whereas p utrescine and diaminohexane had little effect. The mechanical strength of these crosslinked gels is currently being assessed to determine th e optimum composition in terms of cell growth and biocompatibility, an d strength.