Effect of Thermal Processing on the Dynamic/Isothermal Crystallization and Cytocompatibility of Polylactic Acid for Biomedical Applications

Polylactic acid (PLA) is a semi-crystalline biopolymer with numerous applications in tissue engineering and regenerative medicine. PLA biodegradable devices are usually manufactured by extrusion or injection molding. The crystalline-amorphous structure that PLA acquires during processing is relevant for its applications as it determines the biodegradation rate as well as the mechanical properties of the final device. This work focuses on the effect of processing and the effect of crystallization conditions over the crystallization kinetics of two PLAs: poly-l-lactic acid (PLLA) and poly-l,d-lactic acid (PLDA). The cytocompatibility of PLLA and PLDA as a function of processing and crystalline degree has also been studied. It is observed that processing affects crystallization kinetics of PLA increasing the crystallization rate of PLLA and PLDA. Finally, crystallinity influenced cytocompatibility of polymeric surfaces, as the viability of human progenitor cells increased on surfaces with higher crystalline fraction.