The apatite forming ability of micro- and nanocomposites of α-Tricalcium phosphate/poly (D,L-lactide-co-glycolide)

Abstract

ABSTRACTBioresorbable composites consist of micro- and nano-sized α-tricalcium phosphate (α-TCP) particles in a poly(D,L-lactic-co-glycolic acid) (PLGA) matrix were compared for their ability to form bone-like apatite in simulated body fluid (SBF). Due to the uniform distribution of α-TCP nanoparticles over the nanocomposite surface, enhanced apatite formation was observed. This enhanced apatite formation was achieved through faster and more uniform apatite nucleation. The presence of abundant high energy boundaries between α-TCP nanoparticles and PLGA matrix in nanocomposite provided a large number of suitable sites for calcium phosphate (CaP) nucleation. A homogeneous distribution of CaP nuclei formed after 5 days. The resulting apatite crystals grew to form a flake-like apatite layer. In contrast, CaP nucleation was only observed on the micrometre-size α-TCP particles in the microcomposite. After 14 days, a dense flake-like apatite was visible covering the surface of nanocomposite, whilst this surface layer was formed only on α-TCP particles in microcomposite.