Fabrication of polylactic acid/polyethylene glycol (PLA/PEG) porous scaffold by supercritical CO₂ foaming and particle leaching

PLA/PEG/NaCl blends were melt-blended followed by gas foaming and particle leaching process to fabricate porous scaffold with high porosity and interconnectivity. A home-made triple-screw compounding extruder was used to intensify the mixability and dispersion of NaCl and PEG in the PLA matrix. Supercritical carbon dioxide was used as physical blowing agent for the microcellular foaming process. Sodium chloride (NaCl) was used as the porogen to further improve the porosity of PLA scaffold. This study investigated the effects of PEG and NaCl on the structure and properties of the PLA-based blend, as well as the porosity, pore size, interconnectivity, and hydrophilicity of porous scaffolds. It was found that the incorporation of PEG and NaCl significantly improved the crystallization rate and reduced viscoelasticity of PLA. Moreover, scaffolds obtained from PLA/PEG/NaCl blends had an interconnected bimodal porous structure with the open-pore content about 86% and the highest porosity of 80%. And the presence of PEG in PLA/NaCl composite improved the extraction ability of NaCl particles during leaching process, which resulted in a well-interconnected structure. The biocompatibility of the porous scaffolds fabricated was verified by culturing fibroblast cells for 10 days.