Enhancing the functionality of biodegradable Mg–Zn–Mn alloys using poly(lactic) acid (PLA) coating for temporary implants

Polylactic acid (PLA) was coated on biodegradable Mg–Zn–Mn alloys using a sol–gel coating technique for temporary implant applications. The presence of smooth, dense, crack-free PLA coating was evidenced using Fourier transform infrared spectroscopy (FTIR) and a scanning electronic microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDX) module. The strength of the bond between PLA and the Mg–Zn–Mn alloys was investigated as per ASTM D3359 and found to be 4B. The degradation behavior was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy in a simulated body fluid (SBF) solution. The corrosion rate of the PLA–Mg–Zn–Mn sample was found to be 0.00363 mm/y, which is 73% better than the bare Mg–Zn–Mn sample (0.00493 mm/y). In addition, the results of the cytotoxicity assay indicated the cytocompatibility of the implant material on MG-63 osteoblast-like cells, confirming its safety on the bone cells. The efficacy of the use of PLA coating on the biodegradable Mg–Zn–Mn is due to the synergistic effect of both physical and chemical interactions between the PLA layer and the substrate.