Surface Modification of Brass via Ultrashort Pulsed Direct Laser Interference Patterning and Its Effect on Bacteria-Substrate Interaction

In recent decades, antibiotic resistance has become acrucial challengefor human health. One potential solution to this problem is the useof antibacterial surfaces, i.e., copper and copper alloys. This studyinvestigates the antibacterial properties of brass that underwenttopographic surface functionalization via ultrashort pulsed directlaser interference patterning. Periodic line-like patterns in thescale range of single bacterial cells were created on brass with a37% zinc content to enhance the contact area for rod-shaped Escherichia coli (E. coli). Although the topography facilitates attachment of bacteria tothe surface, reduced killing rates for E. coli areobserved. In parallel, a high-resolution methodical approach was employedto explore the impact of laser-induced topographical and chemicalmodifications on the antibacterial properties. The findings revealthe underlying role of the chemical modification concerning the antimicrobialefficiency of the Cu-based alloy within the superficial layers ofa few hundred nanometers. Overall, this study provides valuable insightinto the effect of alloy composition on targeted laser processingfor antimicrobial Cu-surfaces, which facilitates the thorough developmentand optimization of the process concerning antimicrobial applications.