Investigating PLGA/HA composite coating for improved corrosion resistance and mechanical integrity of biodegradable Mg alloys

Magnesium (Mg) alloys are promising biodegradable materials for next-generation orthopaedic implants; however, their rapid degradation and early mechanical failure in physiological environments hinder clinical translation. In this study, a PLGA/HA composite coating was developed on the AZ31 Mg alloy via the sol-gel dip-coating technique to overcome these limitations. The uncoated AZ31 exhibited an Ecorr of −1.44 V and Icorr of 8.30 × 10−4 A cm−2, while the coated sample showed an improved Ecorr of −0.72 V and a reduced Icorr of 4.46 × 10−6 A cm−2, corresponding to a ten-fold decrease in corrosion rate. Hydrogen evolution rate was limited to 0.16 mL cm−2 day−1, and pH remained near-physiological (7.46), confirming the coating's corrosion-suppression ability. After 21 days in SBF, the coated samples retained 74% of their ultimate compressive strength and 89.5% elongation, demonstrating preserved mechanical integrity. These findings support the potential of PLGA/HA coatings in enhancing the durability and biocompatibility of Mg-based bioimplants.