Bioinspired Zinc-doped Nano Hydroxyapatite Reinforced Poly(lactic acid) Composites for Bone Repair

Abstract

Bone defects remain a major clinical challenge due to the slow rate of recovery, complex surgical procedures, and great impact on the lives of patients. Therefore, the development of biocompatible, durable, degradable artificial bone grafts is highly desirable. Inspired by the natural composition of human bone, this study reports the fabrication of poly(lactic acid) (PLA)/zinc-doped hydroxyapatite (Zn-HA) composite materials via the melt blending method. The chemical properties, mechanical performance, degradability, and biocompatibility of the composites were evaluated systematically. Among them, the 10 wt% PLA/Zn-HA composite exhibited optimal performance, including high tensile and flexural strengths, superior thermal stability, and the lowest degradation rate. Controlled degradation and sustained release of zinc ions further enhance osteoblast activity with low cytotoxicity. Furthermore, Alkaline Phosphatase (ALP) activity and Alizarin Red S (ARS) staining confirmed that the 10 wt% PLA/Zn-HA composite significantly promoted osteogenic differentiation. By simultaneously achieving mechanical reliability and enhanced biological properties, this study provides promising design criteria for next-generation artificial bone grafts for bone defect repair.