In Vitro Bacterial Growth on Titanium Surfaces Treated with Nanosized Hydroxyapatite

Bacterial growth on implant surfaces poses a significant obstacle to the long-term success of dental and orthopedic implants. There is a need for implants that promote osseointegration while at the same time decreasing or preventing bacterial growth. In this study, the existing methods for the measurement of bacterial biofilms were adapted so that they were suitable for measuring the bacterial growth on implant surfaces. Two different strains of bacteria, Pseudomonas aeruginosa and Staphylococcus epidermidis, were used, and the in vitro effect of bacterial growth on titanium surfaces coated with an ultrathin (20-40 nm thick) layer of nanosized hydroxyapatite (nHA) was investigated. After 2 h of biofilm growth, there was a 33% reduction in both S. epidermidis and P. aeruginosa bacteria on nHA compared to Ti. For a more mature 24 h biofilm, there was a 46% reduction in S. epidermidis and a 43% reduction in P. aeruginosa on nHA compared to Ti. This shows that coating nHA onto implants could be of benefit in reducing implant-related infections.