Effectiveness of titanium nitride silver coatings against Staphylococcus spp. in the presence of BSA and whole blood conditioning agents

Abstract

Implanted medical devices are at risk of developing an infection at the surgical site. Once a medical implant is inserted, it initially becomes coated by a conditioning film, followed by bacterial retention. In the present study, medical grade stainless steel substrata were coated with titanium nitride (TiN) or titanium nitride/silver (TiN/14.94 at.%Ag or TiN/19.04 at.%Ag). Surface analysis determined that with increased silver concentration, silver nanoparticles were heterogeneously distributed throughout the coatings. The effect of bovine serum albumin or whole blood conditioning agents on the antimicrobial activity and microbial retention were determined using Staphylococcus aureus or Staphylococcus epidermidis. The presence of the conditioning agents reduced the antimicrobial effect of the surfaces against S. aureus. When the cells and conditioning agents were applied together, a reduction in bacterial retention and conditioning film was observed. These results suggest that the impact of conditioning agents should be considered since conditioning films may reduce bacterial retention but may also decrease the antimicrobial properties of the surface coatings.