Biomimetic construction of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/apatite composite materials by an alternate incubation process

The porous PHBV scaffold was pre-soaked in a saturated Ca(OH)2 solution for 7 days and incubated in 100 mM CaCl2/Tris and Na2HPO4/Tris solutions alternatively for up to seven cycles. Thus a novel three-dimensional composite scaffold material consisting of apatite biomimetically deposited on a PHBV matrix was constructed and characterized. SEM images show that nano-sized crystals with needle-like morphologies are deposited preferably at the sites of micro-pores in scaffold walls. Crystals grow larger and denser with the number of incubation cycles, in accordance with the increasing characteristic peaks of apatite in the XRD patterns. Apatite crystals generated from Tris-free solutions, however, present flake-like morphology and aggregate into ball shape, indicating that pH values may affect the morphologies of apatite formed under aqueous conditions. With the excellent biocompatibility and bioactivity of apatite coating layer, this highly porous biodegradable organic/inorganic composite is expected to be desirable for bone tissue engineering.