Release-type bacteriostasis of Cu-bearing stainless steel against planktonic bacteria served in liquid system

Abstract

Cu-bearing stainless steel (SS) with excellent broad-spectrum antibacterial property while maintaining the original mechanical properties of SS may quite be a more advantageous substitute for ordinary SS. Compared with its performance of directly inactivating the attached bacteria, the ability of Cu-bearing SS to kill planktonic bacteria for the applications in liquid system is still challenging ambiguous. Therefore, in this study, a corrosive medium containing chloride ions was applied to investigate that the service of SS in a liquid environment, such as water treatment system. The ions release behavior, release-type bacteriostasis against planktonic bacteria and the evolution of corrosion resistance for Cu-bearing 304L SS were investigated. Electrochemical test combined with X-ray photoelectron spectroscopy measurement proved that the passive film on 304L-Cu SS exhibited a significant game behavior including dissolution and repair processes, which eventually tends to be stable, ensuring the corrosion resistance in service. Compared with the artificial configuration solution with the same concentration of Cu ions, the antibacterial test confirmed that a better antibacterial performance against planktonic bacteria of the leach liquors derived from 304L-Cu SS. In particular, reactive oxygen species overexpression induced by the synergistic effect of multiple metal ions acted a crucial part in clarifying the relevant mechanism of bacteriostasis.