Apatite-forming ability of bioactive poly(L-lactic acid)/grafted silica nanocomposites in simulated body fluid

Bioactive PLLA/surface-grafted silica (g-SiO2) nanocomposite scaffolds were fabricated by solid-liquid phase separation method. And solid PLLA/g-SiO2 nanocomposite films were prepared by solution casting method. A series of parallel tube-like morphology and internal ladder-like structure of PLLA/g-SiO2 nanocomposite scaffolds were observed by SEM. The formation of bone-like apatite in the simulated body fluid (SBF) was characterized by XRD, IR, SEM, EDS and weight measurement. The silica incorporation favors the formation of apatite. The growth of apatite with immersion time is found on the surfaces of both the PLLA/g-SiO2 nanocomposite scaffolds and the films. The potential mechanism is that silanol groups of g-SiO2 in the nanocomposites serve as nucleation sites for the formation of bone-like apatite crystals. (C) 2011 Elsevier B.V. All rights reserved.