Effect of chitosan on octacalcium phosphate crystal growth

Chitosan has a strong effect on the crystallization of octacalcium phosphate. Octacalcium phosphate (OCP) is considered as one of the precursors in bony tissue formation. Chitosan is a polysaccharide prepared by chemical N-deacetylation of chitin. The interactions between the crystal and the polymer have been demonstrated by the growth of OCP crystals in the presence of soluble chitosan using the method of constant composition. These interactions correspond to a Langmuir adsorption type. The adsorption of chitosan on the OCP crystal surface is controlled by electrostatic interactions between the NH3+ functions of the polymer and negative groups on the crystal surface (HPO42-). So, pH has a strong effect on the adsorption of chitosan. Copyright (C) 1996 Elsevier Science Limited.