Modulating antibacterial properties of titanium surface coatings: The role of low intensity pulsed ultrasound and light stimuli

Medical titanium and titanium alloys were susceptible to infection following implantation due to their limited antibacterial properties. One effective approach to mitigate this risk was the application of antibacterial coatings on the medical titanium materials surface. Additionally, there was a pressing need in clinical practice to develop a titanium surface coating that can modulate antibacterial properties in response to external conditions. In this study, a zinc oxide-loaded silver nanorod arrays coating was fabricated on the titanium surface using intensity pulsed ultrasound and light as stimuli, aiming to achieve the desired regulation of antibacterial properties. The coating morphology and the silver distribution within the coating were investigated. The surface roughness and wetting angle were tested. The effect of low intensity pulsed ultrasound and light on the cumulative release of silver ions was studied, and its mechanism was analyzed. The bacteriostasis rate of the polarized ZnO-loaded silver nanorods array coating reached 99.96%. The synergistic bactericidal mechanism of piezoelectric effect, catalysis, silver ion bactericidal effect and nanorod puncture effect on bacteria was expounded. Finally, the ZnO-loaded silver nanorod array coating exhibited non-cytotoxicity and supported full osteoblast adherence morphology. The polarized coating was observed to be coated with abundant granular hydroxyapatite after immersion in simulated body fluids for 7 days. The results provide a possibility for modulating the antibacterial properties of titanium surface coatings in vitro.