Structural and mechanical characteristics of collagen tissue coated with chitosan in a liquid CO/water system at different pressures.

Chitosan coatings of biological heart-valve prostheses enhance their biocompatibility, resistance to pathogenic microflora and lifetime. Collagen tissues can be coated with chitosan in aqueous solution acidified, to make chitosan soluble, with HCO formed from a coexisting liquid CO phase under pressure. The advantage of HCO is that it can be easily removed after the coating procedure.