Fabrication Of Polylactide Porous Scaffolds For Bone Tissue Engineering

Polylactide(PLA) and its copolymers(PLGA) are biocompatible polymers and have extensive application in tissue engineering. In this paper, porous PDLLA, PLGA scaffolds with good three-dimensional microstructure were fabricated by solvent casting/porogen leaching method combining freeze-drying process using ice particulates as porogen. The effect of technical factors on morphology of porous scaffolds was studied, too. It is showed that the scaffolds possess good three- dimensional microstructure and no remained porogen. The pore size and porosity were controlled by the size and mass fraction of ice particulates. The toxicity of the scaffolds was Class 0 or Class 1 and they could be used in bone tissue engineering.In order to improve the connectivity in porous scaffolds prepared by above process. Seepage equipment was designed according to seepage principle in foundry. The principle of pore forming was analyzed and the theoretical filling pressure was calculated. The influence of technical factors such as concentration of polymer solvent, filling pressure and ice size on fabrication was studied using orthogonal experiment. The research results showed if the formability is the only one factor to be considered, that the effect of ice size was more than the concentration of polymer solvent and filling pressure. The optimized parameters are concentration of polymer solvent 1:8g/ml, filling pressure 0.085-0.08 MPa and ice size 900-1000μm.The methods of improving compressive strength of PLA porous scaffolds were studied and it showed that hot water soaking and gelatin coating could both increase the compressive strength of porous scaffolds markedly, and the latter have the better effect. Gelatin casting can also improve hydrophilicity of porous scaffolds effectively.