Polydopamine-assisted Cd/Cu dual-ions immobilization on titanium surface for the application of antibacterial surgical instruments

Abstract Titanium and its alloys have excellent mechanical and biocompatibility features, which are commonly utilized in the production of surgical instruments, such as scalpels, surgical tweezers, needle holders, etc. However, lacking antibacterial ability, titanium materials are susceptible to bacterial infection, which hinders the success of surgical operations. Medical titanium substrates were modified using polydopamine (PDA) coatings in this study, followed by cadmium (Cd) and copper (Cu) ions loaded into the PDA coating to endow titanium surgical instruments with antibacterial properties. The surface topography, chemical state, ion release, and other features of the specimen were analyzed. Additionally, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Cd and Cu ions against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were quantitatively determined through serial dilution methodology. The antibacterial features of embellished substrates were investigated against both S. aureus and E. coli. The results demonstrated that the dual-ions (Cd/Cu) modified coating exhibits a reduction in ion release compared to the single ion loaded coatings, with Cd ions demonstrating a 95.13% reduction. Furthermore, the antimicrobial ability of the dual-ions (Cd/Cu) modified coating against S. aureus and E. coli was superior to the PDA coating, with antibacterial rates of 99.89% and 92.04%, respectively. The Cd/Cu co-modified coating demonstrates a balance between low ion release and excellent antimicrobial activity, having great potential for application in antimicrobial surgical instruments.