Abstract: We prepared the electroactive biodegradable nanocomposites PAP/ op-HA/PLGA by blending a triblock copolymer PLA-b-AP-b-PLA (PAP) of polylactide (PLA) and aniline pentamer (AP) with oligomeric lactic acid-surface grafted hydroxyapatite (op-HA)/poly(lactide-co-glycolide)(PLGA). The electrochemical properties and conductivity were characterized using UV-Vis spectroscopy, cyclic voltammetry and standard four-probe method. Film’s surface morphology was displayed by ESEM and contact angle was measured to evaluate the film’s hydrophilicity. Rabbit’s osteoblasts were cultured in vitro on the film surface. For comprehensively evaluating surface properties and biological activity of the new electroactive nanocomposites PAP/op-HA/PLGA for bone repair, cell adhesion and cell spreading (cell area fraction) were determined using fluorescein isothiocyanate dyeing and NIH Image J software analysis, and gene expression levels were detected using Real-time PCR. The results show that PAP/op-HA/PLGA had good electrochemical redox property and low conductivity (~ 5 ? 10-6 S/cm). With the content of 0.1 wt% PAP, the hydrophilicity of composites was improved, the adhesion and expansion of osteoblasts were enhanced, and bone morphogenetic protein-2 (BMP-2) and bone junction protein (osteonectin) gene expression levels were increased, significantly. In conclusion, PAP/op-HA/PLGA composites have good biocompatibility and osteogenic activity.

Key words: Aniline pentamer, Block copolymers, Nano-hydroxyapatite, poly(lactide-co-glycolide), Conductive polymer, Osteogenic activity