Repair of critical size defects in the rat cranium using ceramic-reinforced PLA scaffolds obtained by supercritical gas foaming.

Bioresorbable scaffolds made of poly(L-lactic acid) (PLA) obtained by supercritical gas foaming were recently described as suitable for tissue engineering, portraying biocompatibility with primary osteoblasts in vitro and interesting mechanical properties when reinforced with ceramics. The behavior of such constructs remained to be evaluated in vivo and therefore the present study was undertaken to compare different PLA/ceramic composite scaffolds obtained by supercritical gas foaming in a critical size defect craniotomy model in Sprague-Dawley rats. The host-tissue reaction to the implants was evaluated semiquantitatively and similar tendencies were noted for all graft substitutes: initially highly reactive but decreasing with time implanted. Complete bone-bridging was observed 18 weeks after implantation with PLA/ 5 wt % beta-TCP (PLA/TCP) and PLA/5 wt % HA (PLA/HA) scaffolds as assessed by histology and radiography. We show here for the first time that this solvent-free technique provides a promising approach in tissue engineering demonstrating both the biocompatibility and osteoconductivity of the processed structures in vivo.