In vitro behaviors of hydroxyapatite reinforced polyvinyl alcohol hydrogel composite

Hydroxyapatite (HA) was incorporated into polyvinyl alcohol hydrogel (PVA-H) to form a bioactive composite for applications as artificial cartilage. HA/PVA-H composite containing 2 and 5 wt.% of HA was made for in vitro evaluation. Immersion tests in vitro were performed with PVA-H and HA/PVA-H specimens. XRD, FTIR and SEM were used to characterize the structure and component of specimens. SEM results showed that apatite formed within a short period on HA/PVA-H composite after its immersion in SBF, demonstrating high in vitro bioactivity of the composite. Characteristic peaks of PO43− were enhanced, and new peaks of CO32− were found after immersion on the FTIR experiments. These results proved that the crystalloid deposition on the surface of HA/PVA-H were bone-like apatite. It also found that the precipitation of apatite increased with increase in HA content of the composites, as well as with increasing immersion time for the composite. Mechanical study revealed that the elastic modulus of HA/PVA-H composite increased initially with immersion time in SBF, due to apatite formation on composite surface and kept constant after prolonged immersion in SBF.