Effect of surface modification on interfacial behavior in bioabsorbable magnesium wire reinforced poly-lactic acid polymer composites

Abstract The mechanical behavior, corrosion mechanisms, and cytocompatibility at the interface of magnesium wires reinforced poly-lactic acid polymer composites were studied by in vitro degradation study of 180 days. Surface modification of Mg wires by plasma-electrolytic oxidation improved the interface shear strength from 10.9 MPa to 26.3 MPa which decreased to 8 MPa and 13.6 MPa in Mg/PLA and PEO-Mg/PLA composites, respectively, after 42 days of in vitro degradation. Cross-sections of the composite showed good cytocompatibility, although the cells tended to migrate towards the PLA regions and avoided the surface of the Mg wires. Corrosion of Mg wires (without surface modification) was very fast in composite while corrosion of surface-modified Mg wires was significantly reduced, hydrogen gas was suppressed and only 3% mass loss of Mg wires was found after 180 days. Finally, the corrosion mechanisms at interface were discussed for both composites.