Fabrication and evaluation of silver-doped magnesium oxide nanocomposite coatings for orthopaedics applications

Stainless steel 316 L (SS 316 L) is primarily used as implant material in orthopaedic applications for the treatment of bone fractures and joint replacement surgeries due to its excellent mechanical strength and costeffectiveness. However, its long-term implication, susceptibility to infection and subsequent lack of integration with surrounding tissues remain significant challenges resulting in implant failure. To address these issues, the development of advanced coatings with improved antibacterial properties, biocompatibility, wear and corrosion resistance is of paramount importance. In this study, the potential of an Ag doped MgO nanocomposite coating on stainless steel 316 L substrates has been explored for orthopaedic applications. The Ag-MgO nanocomposite was synthesised using the hydrothermal method. The composition, crystallinity, and morphology of the synthesised nanocomposite was investigated using different techniques such as X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with an energy dispersive X-ray (EDX) attachment. SEM and XRD results confirmed, that the synthesised nanocomposite had a platelet shape with a cubical crystal lattice network and an average size of about 10 nm. The spin coating technique was employed to produce an Ag-MgO nanocomposite coating onto the SS 316 L substrate. The bactericidal efficiency of Ag-MgO nanocomposite-coated SS 316 L substrates was examined against Staphylococcus aureus and Escherichia coli bacteria using well diffusion method, while an MTT assay was performed to determine the cytotoxicity of the uncoated and coated SS 316 L substrate against mouse embryonic fibroblast cell line (NIH-3T3). The effectiveness of wear and friction resistance of Ag-MgO nanocomposite-coated substrate was also evaluated via a ball-on-disc tribometer. Furthermore, corrosion behaviour evaluation using a linear polarisation resistance method confirms the significant improvement in corrosion resistance of coated substrate than the uncoated substrate. Overall, the results demonstrated that the Ag-MgO nanocomposite coating on SS 316 L substrates improves its performance for orthopaedic applications.