Preparation and properties of chitosan/calcium phosphate composites for bone repair

Chitosan/calcium phosphate (CaP) composites composed of bioactive calcium phosphate and flexible chitosan were made by a simple mixing-and-heating method. Phase composition, morphology, and mechanical properties - including in-air and in vitro fatigue behavior - were evaluated. Experimental results showed that the chitosan matrix did not affect the crystalline phase of CaP. However, the content of CaP additive affected the three-point bending strength of the composites. A CaP/chitosan ratio of 5% by mass to volume in the composite achieved the significantly highest bending strength of 45.7 MPa. Stability of chitosan/CaP hybrid composites was apparently affected by in vitro cyclic loading. Nonetheless, when applied a loading stress of 11.4 MPa, the sample containing the optimal 5 mass/vol% CaP lasted 40 minutes in in vitro fatigue test until failure occurred. It was thus concluded that hybrid biocomposites with initial high strength might be a potential implant candidate for bone defect repair.