Highly porous polycaprolactone-45S5 Bioglass® scaffolds for bone tissue engineering

Highly porous biocompatible composites made of polycaprolactone (PCL) and 45S5 Bioglass® (BG) were prepared by a solid-liquid phase separation method (SLPS). The composites were obtained with BG weight contents varying in the range 0-50%, using either dimethylcarbonate (DMC) or dioxane (DIOX) as solvent, and ethanol as extracting medium. The porosity of the scaffolds was estimated to be about 88-92%. Mechanical properties showed a dependence on the amount of BG in the composites, but also on the kind of solvent used for preparation, composites prepared with DIOX showing enhanced stress at deformation with respect to composites prepared with DMC (stress at 60% of deformation being as high as 214 ± 17 kPa for DIOX-prepared composites and 98 ± 24 kPa for DMC-prepared ones, with 50 wt/wtPCL% of glass), as well as higher elastic modulus (whose value was 251 ± 32 kPa for DIOX-prepared scaffolds and 156 ± 36 kPa for DMC-prepared ones, always with 50 wt/wtPCL% of glass). The ability of the composites to induce precipitation of hydroxyapatite was positively evaluated by means of immersion in simulated body fluid and the best results were achieved with high glass amounts (50 wt/wtPCL%). In vitro tests of cytotoxicity and osteoblast proliferation showed that, even if the scaffolds are to be considered non-cytotoxic, cells suffer from the scarce wettability of the composites.