Collagen and its interaction with chitosan. II. Influence of the physicochemical characteristics of collagen.

This work is a continuation of the study of the interactions which can occur when chitosan is in contact with bovine anticollagen. The major result of the first part was that under classical conditions, there exists a competition between collagen gelation and the formation of a pure polyanion-polycation complex with chitosan. In the present study, we have attempted to reach the 1:1 stoichiometry by two different methods. When collagen is denatured, the polyanion-polycation complex is improved, but the theoretical stoichiometry is not achieved. The presence of a large excess of chitosan gives rise to a second mechanism of interaction. Contrary to the case of the polyanion-polycation interaction, the latter seems to induce the denaturation of collagen. This behaviour is confirmed by infrared and circular dichroism spectrometries, as well as differential scanning calorimetry.