Biopolymer Polyelectrolyte Complex – Hydroxyapatite Composites for Bone Tissue Engineering

The excellent biocompatibility, biofunctionality, and non-antigenic property make chitosan an ideal material for tissue regeneration. In addition to that its hydrophilic surface promotes cell adhesion, proliferation, and differentiation, and evokes a minimal foreign body reaction on implantation. In spite of these favorable properties, the inadequate mechanical strength and loosening of structural integrity under wet conditions, limit its application for bone tissue engineering. To improve the suitability of chitosan for bone tissue engineering, we have biomimetically synthesized composites of chitosan, polygalacturonic acid and hydroxyapatite. Polygalacturonic acid (PgA) is biocompatible, biodegradable and electrostatically complementary to chitosan. The strong interactions between negatively charged carboxylate groups of PgA and positively charged amino groups of chitosan lead to complex formation. This biopolymer complex provides improved mechanical strength and better structural integrity under wet condition. In this study, we have investigated the applicability of chitosan-PgA-hydroxyapatite composites for bone tissue engineering.