PLLA/PLA scaffolds prepared via Thermally Induced Phase Separation (TIPS): tuning of properties and biodegradability

Foams for tissue engineering applications were prepared via thermally induced phase separation (TIPS). Poly-L-Lactic Acid (PLLA) and blends of PLLA with PLA in different proportions were used (100/0, 90/10, 75/25, 50/50, 0/100 PLLA/PLA wt/wt) starting from ternary systems where dioxane was the solvent and water the non-solvent. Morphology was evaluated by Scanning Electron Microscopy (average pore size and interconnection) and the void fraction was measured by means of Hg porosimetry. Foams apparent density was also evaluated (porosity ranges from 87% to 92%). Biodegradability was estimated in a body mimicking fluid. Results show that structure and morphology (in terms of average pore size and distribution, interconnectivity and mechanical properties) depend upon the combination of the operating conditions adopted for the process (polymer concentration, solvent/non-solvent ration, demixing temperature and time). Furthermore, by blending PLLA with PLA it is possible to tune the biodegrability of the foam, thus addressing the possible applications in different fields of soft tissue engineering.