D-Cysteine functionalised silver nanoparticles surface with a “disperse-then-kill” antibacterial synergy

In this study, antibacterial surfaces with a “disperse-then-kill” synergy were prepared by embedding D-cysteine (D-cys) functionalised silver nanoparticles (AgNPs) onto polydopamine-coated stainless steel. The as-prepared surface exhibited excellent antibacterial performance against the gram-negative Escherichia coli and Pseudomonas aeruginosa PAO1 and gram-positive Staphylococcus aureus. This component of D-cys could inhibit the formation of mature biofilms and maintain bacteria in dispersed and planktonic states, which further facilitates the bacterial-killing action enabled by the AgNPs. The cooperation of these two components presents a new strategy for developing antibacterial surfaces with a stronger and more durable performance. Furthermore, the as-prepared surface did not exhibit an apparent cytotoxicity based on the results of real-time cell analyzer (RTCA) and a cell viability kit-8 assay (CCK-8 assay). Given these results, the proposed antibacterial strategy demonstrated a potential to inhibit bacterial adhesion and biofilm formation on surgical devices and medical implants.