Development of poly(vinyl alcohol)-collagen-hydroxyapatite nanohybrids for tissue grafting

Poly(vinyl alcohol) (PVA) was introduced during in situ synthesis of hydroxyapatite (HA) in neutral collagen (COL) solution and final PVA-COL-HA nanohybrids were achieved via sequential steps including gelation by fibrillogenesis, freezing-thawing physical crosslinking, removal of unreacted residues and dehydration. This method is expected to endow the pure PVA with good bioactivity and meanwhile the presence of elastic PVA would improve the properties of COL-HA composites. The phase, microstructure and possible molecular interactions of the achieved PVA-COL-HA nanohybrids were analyzed by using X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy. The results indicate that the inorganic phase is poorly crystallized apatite with a nanometer size due to the confinement of organic macromolecules which forms a network structure.