Titanium is commonly used in indwelling devices, including orthopedic and dental prostheses and cardiac valves, maxiofacial surgery and vascular stents, because of its high biocompatibility, low toxicity and high corrosion resistance. The use of these implants is diversifying and increasing.
It is well-documented that biofilm formation by human pathogenic bacteria on medical implants can be dramatic, leading to failure of the device and requiring its surgical removal for the patient; this can be associated with systemic infection, loss of function, amputation or death. Biofilm removal from indwelling devices is an issue of concern. Staphylococcus aureus strains, in particular, have been reported to be a significant contributor to infections associated with orthopedic implants, and therefore understanding the attachment characteristics of S. aureus to host tissues and inanimate surfaces is critical in order to reduce instances of infection.
Different approaches for the prevention of bacterial attachment to medical implant surfaces have been developed. These include chemical functionalization of the surface, application of antimicrobial coatings or attaching metallic nano particles to the implant surface. Any harmful bacteria have, however, developed resistance to many common antimicrobial agents, and therefore functionalizing the surfaces of implants with such agents may have limited success. A new generation of antibacterial surfaces, so-called ‘mechano-responsive bactericidal surfaces’ provide an alternative to existing technologies. In this study, we report the bactericidal effect of nano-structured titanium (commercial purity Grade 2) surfaces fabricated using hydrothermal etching in a highly alkaline solution on Staphylococcus aureus CIP 65.8 and Pseudomonas aeruginosa ATCC 9025. The chemical composition, wettability, surface nano-topography and nano-architecture of the titanium substrates were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry and goniometry.