A Gallic Acid-Doped Polypyrrole Coating with Anticorrosion and Antibacterial Properties on Magnesium Alloy

Magnesium (Mg) and its alloys exhibit great potential as biomedical implants due to their excellent biological performance and mechanical properties. However, their clinical applications are limited by their rapid corrosion rate in physiological media and the risk of implant-associated infections. Herein, a multifunctional polypyrrole/gallic acid (PPy/GA) coating was deposited on an AZ31 Mg alloy substrate by electrochemical polymerization to enhance simultaneously the corrosion resistance and antibacterial properties of the Mg alloy. Electrochemical and in vitro immersion tests demonstrated that the anticorrosion performance of the Mg alloy was significantly improved with the PPy/GA coating. The thiazolyl blue tetrazolium bromide (MTT) assay and live-dead staining of L929 cells indicated the acceptable cytocompatibility of the PPy/GA coating. In vitro antibacterial tests revealed a remarkable enhancement in the antibacterial activity of the PPy/GA-coated Mg alloy compared with the PPy-coated material and the bare Mg alloy.