Investigation on Bioactive Antibacterial and Biocompatible Coating on Titanium Alloy for Biomedical Applications

Abstract

Current research investigates the plasma electrolytic oxidation (PEO) coating of a vanadium newlinefree Ti-6Al-7Nb alloy to optimise its surface properties for biomedical applications. The PEO newlineprocess was performed in an alkaline electrolyte including Naand#8322;SiOand#8323;, Naand#8323;POand#8324;·12Hand#8322;O, and KOH, newlinewith varied duty cycles (20-60%), frequencies (400-2000 Hz), currents (100-300 mA), and newlinetreatment periods (5-25 minutes). Surface characterisation was carried out using X-ray newlinediffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy newline(SEM). The study found that raising the frequency reduces coating thickness (from 27.76 µm newlineat 400 Hz to 16.39 µm at 2000 Hz), while larger duty cycles and current levels greatly enhance newlinecoating hardness (883.35 HV at 60% duty cycle and 862.09 HV at 300 mA). Electrochemical newlinetests demonstrated improved corrosion resistance in a 0.9% NaCl solution. Grey relationship newlineanalysis determined that the ideal PEO parameters for maximising coating thickness (32.96 newlineµm) and surface roughness (3.37 µm) are a 50% duty cycle, 500 Hz frequency, 300 mA current, newlineand 7.5-minute processing time. Biocompatibility tests revealed that it has a higher cell newlineviability (94.53%) than both uncoated Ti-6Al-7Nb and PEO-coated Ti-6Al-4V ELI, indicating newlinethat it is suitable for implant applications. Furthermore, adding silver nanoparticles (AgNPs) newlinegreatly improved antibacterial activity against Staphylococcus aureus and Escherichia coli, newlineresulting in the highest inhibition zones (17.33 mm and 17.5 mm, respectively) at a newlineconcentration of 1.5 g/L AgNPs. These findings establish PEO-coated Ti-6Al-7Nb as a highly newlinepromising biomedical material, with increased corrosion resistance, mechanical strength, newlinebiocompatibility and antibacterial activity. newline