Collagen and its interactions with chitosan, III some biological and mechanical properties.

Bovine atelocollagen and high molecular weight fully deacetylated chitosan, depending on the conditions, can form complexes whether by means of purely electrostatic interactions or by hydrogen bonding. In the first case the maximum proportion of chitosan in the complex is relatively low (approximately 10%) and then it is difficult to conclude whether chitosan prevents collagen digestion by collagenase or not. On the contrary, in the case of the second kind of complex, chitosan induces a strong protection toward the specific enzyme. If we consider the mechanical properties of polyanion/polycation complexes, chitosan brings softening rather than hardening to the system and the complex behaves like some polymer blends.