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The present study reports a three-step bio-safe process for fabricating porous polylactic acid (PLA) scaffolds with a biomimetic design of the porosity and the architecture and applications in bone tissue engineering (bTE). The process starts with a PLA-ethyl lactate solution and involves the combination of thermal induced phase separation (TIPS) and supercritical CO2 (scCO2) drying techniques for the development of a nano-fibrous architecture. In a third step, it was further combined with a gelatin leaching technique to create an additional interconnected network of large pores of appropriate size and distribution. The effect of the size of the gelatin particles, selected in three different ranges: 100-200, 200-400 and 400-600 μm, on the morphology, porosity and textural features of PLA scaffolds is assessed by means of scanning electron microscopy analysis, gravimetric measurements, image analysis and low-temperature N2 adsorption. Finally, in vitro cell culture tests are carried out by using human osteosarcoma cell line MG63 in order to evaluate the biological response of the different scaffolds prepared and to assess their potential for bTE applications.

Partially biodegradable porous scaffolds incorporating bioactive molecules prepared by clean techniques posses an enormous interest in tissue engineering applications. Poly(methyl methacrylate)–poly( l -lactic acid) (PMMA–PLA) blends were submitted to CO2 supercritical conditions (P = 160–260 bar, T = 60 °C) after certain time and then rapidly depressurized to obtain porous structures that have been related with the supercritical parameters and to the polymer blend composition. In some cases ibuprofen was also incorporated to the formulations previously to the CO2 treatment and studied the appropriate conditions for avoiding its extraction in SCCO2. Scaffolds purity, thermal transitions, swelling and degradation behaviour, and the ibuprofen release were also studied to determine the appropriate scaffolds with a desired porosity for cell seeding. Cell culture was performed on the selected porous scaffolds using human fibroblast examined by scanning electron microscopy (SEM).