Bactericidal nanospike surfaces via thermal oxidation of Ti alloy substrates

With the aim to fabricate bio-inspired antibacterial nanotopography surfaces, nanospikes with varying dimensions were grown on Ti alloy surfaces using a thermal oxidation method. By controlling the acetone vapour concentration inside the tube furnace, the resulting oxide surface changed from nanocolumn shapes to nanospikes with approximately 20 nm diameters. The nanospikee growth was demonstrated to work on 3D Ti alloy bead surfaces, which means translation of the method to implant surfaces would be possible. Microbiology studies using Escherichia coli. showed that the nanospikes on the Ti alloy surfaces has potential to reduce bacterial viability. More dead bacteria were present on the nanospike surfaces compared to a smooth control and a 40% reduction of viability was noted in bacterial suspensions incubated with a nanospike surface. It was shown that by annealing the Ti alloy surfaces prior to thermal oxidation, it is possible to grow vertically aligned nanospikes. This could be highly valuable when designing implant surfaces with antimicrobial properties.