High strength PLGA/Hydroxyapatite composites with tunable surface structure using PLGA direct grafting method for orthopedic implants

Poly (Lactic-co-Glycolic Acid) (PLGA) based bio-composites for orthopedic implants are becoming more important as surgical techniques develop. Enhancers such as hydroxyapatite (HA) are used to enhance the biocompatibility and bone formation. Studies on HA surface treatment have been proposed to enhance the bonding force between particles HA and PLGA. Conventional monomer-based grafting techniques have limitations in copolymer grafting and improving mechanical strength of composites. In this study, PLGA can be directly grafted to HA surface in polymer state using melt grafting with transesterification. With this method, the grafting efficiency of PLGA is improved compared to previous studies. The grafting efficiency of PLGA was analyzed and the structure at the surface was confirmed. It was confirmed that a polymer having a large molecular weight can be grafted on the HA surface when PLGA is in an abundant state by indirectly analyzing the size of the grafting polymer through molecular weight evaluation. A composite materials using PLGA-g-HA prepared under optimized conditions have tensile strengths increased by more than doubled compared with a n-HA blended composite. The direct grafting technique of polymer was found to be effective in forming the anchoring structure between HA particles and PLGA.