Green synthesis of MgO nanoparticles using Mangifera indica extract and their electrophoretic deposition on Ti6Al4V for antibacterial application

Titanium alloys such as Ti6Al4V are widely used in biomedical implants; however, their susceptibility to bacterial colonization remains a major challenge. In this work, magnesium oxide (MgO) nanoparticles were synthesized via a green route using Mangifera indica peel extract and subsequently deposited onto Ti6Al4V substrates by electrophoretic deposition (EPD) to explore their potential as antibacterial coatings. Following thermal analysis, the synthesized powders were calcined at 500 °C (HT500) and 700 °C (HT700). XRD and Rietveld refinement confirmed the formation of crystalline cubic MgO, with phase purities of 82.01 wt.% and 98.72 wt.% for HT500 and HT700, respectively. Crystallite size increased with calcination temperature, reaching approximately 62 nm for HT700 according to Rietveld refinement. SEM analysis revealed a transition from highly agglomerated particles to more defined polyhedral morphologies at higher calcination temperatures. The antibacterial activity of HT700 nanoparticles was evaluated against Escherichia coli and Staphylococcus aureus. A concentration-dependent reduction in bacterial viability was observed, with significant inhibition of E. coli from 3 mg/mL and S. aureus from 6 mg/mL onwards. The antibacterial effect was accompanied by an increase in culture medium pH, reaching values close to 10 at the highest nanoparticle concentrations. EPD successfully produced homogeneous MgO coatings on Ti6Al4V substrates, which showed a reduction in bacterial viability, particularly against S. aureus. Overall, these results demonstrate the feasibility of combining green-synthesized MgO nanoparticles with electrophoretic deposition to produce antibacterial Ti-based surface coatings, providing a proof-of-concept for the development of sustainable surface modifications for future biomedical applications.