Preparation and characterisation of composites based on biodegradable polymers for in vivo application

Poly(L-lactic) acid (PLLA), polycaprolactone (PCL), three different copolymers based on poly(L-lactic) acid and polyglycolic acid (PLLA-co-PGA), and their composites with hydroxyapatite obtained from bovine bone (ossein), were tested in order to have information on the thermal, morphological, mechanical and biochemical properties in view of their use as biocompatible/biodegradable materials. Ossein, which is essentially a biological hydroxyapatite, was found to improve the modulus and increase the hydrophilicity of the polymeric substrate. In addition, the size of the ossein particles was found to be critical for the improvement of mechanical properties. Finally, preliminary results on the in vitro biocompatibility of selected blends carded out by using primary cultures of human osteoblasts showed that the presence of hydroxyapatite stimulates a more positive cellular response.