In vitro corrosion and antibacterial properties of layer-by-layer assembled GS/PSS coating on AZ31 magnesium alloys

To enhance the corrosion resistance of magnesium (Mg) alloy and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, Mg(OH)2 films were fabricated on AZ31 magnesium alloy substrates by an in-situ hydrothermal method and well-defined multilayer coatings, consisting of gentamicin sulfate (GS) and poly(sodium 4-styrene sulfonate) (PSS), were prepared via layer-by-layer (LbL) assembly. The morphologies, chemical compositions and corrosion resistance of the obtained (PSS/GS)n/Mg sample were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, electrochemical methods and immersion tests. Finally, the bactericidal activity of (PSS/GS)n/Mg samples against Staphylococcus aureus was assessed by the zone of inhibition methods and plate-counting method. The so-synthesized composite coating on the Mg alloy substrates exhibits good corrosion resistance and antibacterial performance, which make them attractive as coatings for medical implanted devices.