Tuning of biodegradation rate of PLLA scaffolds via blending with PLA

Abstract

Blends of Poly-L-Lactic Acid (PLLA) with Poly-Lactic Acid (PLA) in different proportions (95/5, 90/10, 80/20, 70/30 and 60/40) were utilized in order to realize biodegradable and biocompatible scaffolds for soft tissue engineering applications. The scaffolds were produced via thermally induced phase separation (TIPS) 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). Foams’ apparent density was also evaluated (porosity ranges from 87% to 92%). Moreover an in vitro biodegradation test of scaffolds was set-up in order to verify the rate of degradation of the various PLLA/PLA blends employed. The rate of degradation was calculated via WAXD, by analyzing the increment of cristallinity of the various PLLA/PLA scaffolds mantained for different times in a body mimicking fluid, in the presence or in the absence of cells. The results showed that it is possible to prepare scaffolds of PLLA/PLA via TIPS and to tune their average pore size by changing some experimental parameters (polymer concentration, solvent/non-solvent ratio, demixing temperature and time). The biodegradation tests highlighted some significant differences in terms of degradation rate between the PLLA/PLA foams and pure PLLA foam (used as control). The data confirm that morphology, mechanical properties and biodegrability of the foam using a blend of the scaffolds can be tuned by blending PLLA with PLA.