Preparation of highly porous interconnected poly(lactic acid) scaffolds based on a novel dynamic elongational flow procedure

Abstract

Sodium Chloride (NaCl) is a common porogen to be used in preparing porous scaffolds in tissue engineering. However, NaCl particles are easily broken during melt blending with the matrix polymer by conventional processing techniques, such as twin extrusion, which causes uncontrollable pore size and entrapped residues after leaching in the prepared scaffolds. To address these problems, this study reported a novel scaffold fabrication method based on self-developed vane extruder, which applies global dynamic elongational flow to the polymer compounds. We found that NaCl particles not only preserved their original size, but also could retain high loading content when been blended with poly(lactic acid) (PLA) matrix using vane extruder. Based on these high porogen composites, we are able to prepare PLA porous scaffolds with porosity as high as 93% via supercritical carbon dioxide (Sc-CO2) foaming and particulate leaching hybrid method. Detailed analyses confirmed that the NaCl porogens could be completely leached within 24h. The biocompatibility of the scaffolds prepared was verified by culturing human mesenchymal stem cells. Therefore, the proposed approach based on vane extruder compounding has great potential to be used in tissue engineering scaffold fabrication.