Chitosan (Ch) is one of the most commonly used natural biomaterials. Osteodifferentiation of mesenchymal stem cells (MSCs) on Ch has drawn extensive interest. Hydroxyapatite (HA) is a component of skeleton and teeth with good biocompatibility. Combination with HA may be a good method to modify Ch to facilitate cellular behaviors and functions on it. In this study, Ch/HA film was prepared and characterized. Its potential to benefit cellular behaviors and osteodifferentiation of MSCs was evaluated. Resultantly, physical properties of composite Ch/HA, including water‐in‐air contact angle, tensile strength, elastic modulus, and breaking elongation were favorably modified. In cellular culture medium, Ch/HA films absorbed more Ca2+ than Ch films, and more HA crystalline growths on Ch/HA films. 3‐(4,5‐Dimethythiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay and morphological features showed better proliferation and adhesion of MSCs on Ch/HA films. Osteodifferentiation of MSCs on Ch/HA was promoted, indicated by modified transcription level of osteocalcin, osteopontin, collagen I, alkaline phosphatase (ALP), and induced ALP activity. These data suggest biocompatibility of Ch is modified after being blended with HA, which promotes osteodifferentiation of MSCs. This can be a promising approach to modify Ch for its applications in bone tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1202–1209, 2014.
