Robust Osteoconductive & beta;-Tricalcium Phosphate/L-poly(lactic acid) Membrane via Orientation-Strengthening Technology

L-poly(lactic acid) (PLLA) is a biodegradable materialwith multiplebiomedical application potentials, especially as a membrane for guidedbone regeneration. In terms of its low strength and poor osteogenicactivity, improving these two properties is the key to resolve thelimitations of PLLA for bone-associated applications. Herein, an orientation-strengtheningtechnology (OST) was developed to reinforce PLLA's mechanicalstrength by introducing biocompatible & beta;-tricalcium phosphate(& beta;-TCP) to improve the crystallinity of PLLA, allowing for theformation of a highly oriented architecture to acquire an advancedmembrane with high mechanical property. Furthermore, the additionof & beta;-TCP nanoparticles significantly promotes the osteogenicactivity of the composites. The tensile strength of the membrane containing5 wt % & beta;-TCP was 220 MPa, which was 4-folds that of the nativepolylactic acid fabricated via the conventional method.The oriented microstructure enhanced both the mechanical strengthand the osteogenic activity of the material. The parallel grooveson the material surface are similar to the mineralized collagen fiberson the bone surface, which promoted the growth and differentiationof osteoblasts, with & beta;-TCP further contributing to the osteoconductiveeffect. The combination of & beta;-TCP and orientation-strengtheningeffect endows the material with higher mechanical properties and bioactivities,which provides an advanced manufacturing strategy for the preparationof PLLA-based materials for bone repair.