Bacterial infections account for 20% of premature implant failures resulting in high patient trauma, increased medical costs and an elevated risk of future complications. With escalating implant demand due to rising obesity and ageing populations, together with increasing antimicrobial resistance causing antibiotics to lose their efficacy, it is imperative to develop new strategies to prevent implant infections.
Naturally occurring nanopillars on dragonfly, cicada and butterfly wings have been shown to cause bacterial cell death through physical rupturing of the cell envelope contrary to biochemical activity. Titanium is widely used in orthopaedic and dental implants due to favourable mechanical and biocompatible properties. This study investigates the bactericidal efficacy of titanium dioxide nanospikes grown on both pure and alloyed (Ti64) titanium substrates using the alkaline hydrothermal process.
Systematic time duration study revealed nanospikes arrays with significantly contrasting characteristics, growth homogeneity, height and density. The bactericidal potential of the surfaces was assessed by quantifying the viability of P. aeruginosa and S. aureus cells after nanospike interaction. This study employs a recent quantifying viability technique, Viability PCR (polymerase chain reaction) utilising the DNA modifying dye propidium monoazide.
The titanium surface was also amine functionalised with the alkoxysilane molecule, APTMS, by solution deposition for prospective antimicrobial peptide binding (salinization). This technique was optimised and analysed through Quartz Crystal Microbalance (QCM) and X-ray photoelectron spectroscopy (XPS) investigations.
These results show the alkaline hydrothermal technique is able to generate a bactericidal surface on multiple substrates against both Gram negative and positive bacteria. Viability PCR has the ability to reliably quantify bacterial viability on the bactericidal nanospike surface. Salinization investigations indicate the potential for effective antimicrobial peptide functionalisation on the nanospikes.