In vitro and in vivo study to the biocompatibility and biodegradation of hydroxyapatite/poly(vinyl alcohol)/gelatin composite

Abstract

A novel porous composite material composed of hydroxyapatite, poly(vinyl alcohol) (PVA), and gelatin (Gel) was fabricated by emulsification. Scanning electron microscopy showed that the material had a well-interconnected porous structure including many macropores (100-500 microm) and micropores (less than 20 microm) on their walls. The composite had a porosity of 78% and showed high water absorption up to 312.7% indicating a good water-swellable behavior that is a characteristic of hydrogel materials. When immersed in water, the scaffold's weight continuously decreased. After immersion in simulated body fluid, the weight continuously increased because Ca(2+) and PO(3-) (4) ions deposited on the surface and the internal surfaces of the material pores. The deposit was proved to be carbonated hydroxyapatite by thin-film X-ray diffraction, Fourier transform infrared spectroscopy and energy dispersive X-ray analysis. The composite was detected to be non-cytotoxicity by MTT assay. The HA/PVA/Gel material was also implanted subcutaneously in the dorsal region of adult female rats. After 12 weeks of implantation, the porous material adhered tightly with the surrounding tissue, and the ingrowth of fibrous tissue as well as the material's partial degradation was observed, which partly indicated that the composite was biocompatible in vivo. In conclusion, the porous HA/PVA/Gel composite is a promising scaffold for cartilage tissue engineering with more studies.