Positron annihilation in bioactive glass/poly(glycolide-co-L-lactide) composites

Composites made of bioactive glasses and resorbable polymers are promising biomaterials for bone tissue regeneration. In this study several types of composites produced from bioactive glasses, differing in chemical composition (A2 and S2) and poly(glycolide-co-lactide) (PGLA) were obtained. The resulting composite materials were investigated with positron lifetime spectroscopy and Doppler broadening of annihilation line. It was found that for the composites made of S2 bioglass the intensity of the third positron lifetime component coming from the positronium (Ps) annihilation decreased with increasing in volume fraction of bioglass particles exhibiting behaviour characteristic of microcomposites. For the composites produced from A2 bioglass, such a dependence was not found. The differences obtained may be connected with chemical composition of the bioglass and/or its crystallinity.