The effect of surface roughness and chitosan deposition volume on microbial growth in biofilm involving titanium surfaces for orthopaedic applications

Abstract

Orthopaedic hardware infections are a significant health and economic burden and have been reported to be the cause of many revision surgeries in total hip and knee arthroplasties. Many of these infections are caused by microbial growth in biofilm on the surface of the implanted device. Chitosan surface modifications of fracture fixation implants have shown to reduce infection rates and improve clinical results in orthopaedic procedures. Additional work is needed to determine the role of the chitosan deposition volume and substrate surface roughness on biofilm growth. In this study, titanium alloy discs were prepared to have a range of six surface roughness magnitudes, as well as four different concentrations of chitosan coatings. Analysis of in vitro tests with Staphylococcus aureus (S. aureus) showed that the bacterial concentration in biofilm was significantly affected by surface roughness and chitosan concentration. Titanium surfaces with low to intermediate average roughness values (between 0.1 and 1.5 µm) and higher concentrations of chitosan best inhibited biofilm adhesion. Additional work should explore the mechanisms of chitosan's antibacterial activity.