Biomimetic synthesis of novel polyvinyl alcohol/hydroxyapatite composite microspheres for biomedical applications

Biomimetic composite microspheres of polyvinyl alcohol/hydroxyapatite (PVA/HA) were fabricated for the first time via a synergy of in situ synthesis and emulsification-crosslinking process for biomedical applications. The influences of the HA contents on their phases and morphological features were investigated. The results showed that, when 20 wt% HA was incorporated, the as-prepared PVA/HA composite microspheres exhibited a regular spherical shape, high dispersity and uniform microstructure. Their average particle size was determined as about 39.0 μm. The in situ deposited inorganic phase of the composite microspheres was identified as low-crystalline HA, and its actual content was in close agreement with the theoretical value. After being soaked in simulated body fluid (SBF), the PVA-20%HA composite microspheres were covered with bone-like apatite particles, indicating their good in vitro bioactivity. Vancomycin hydrochloride (VH) was chosen as a model drug. The drug entrapment efficiency and drug loading capacity of the microspheres were found to gradually increase with the increase of HA content. Moreover, the PVA/HA composite microspheres were more effective for releasing VH in a controlled way than their PVA equivalents, among which those containing 20 wt% HA exhibited the best drug release behavior. (paper)