Optical Tracking of Surfactant-Tuned Bacterial Adhesion: a Single-Cell Imaging Study

Probing the interfacial dynamics of single bacterial cells in complex environments is crucial for understanding the microbial biofilm formation process and developing antifouling materials, but it remains a challenge. Here, we studied single bacterial interfacial behaviors modulated by surfactants via a plasmonic imaging technique. We quantified the adhesion strength of single bacterial cells by plasmonic measurement of potential energy profiles and dissected the mechanism of surfactant-tuned single bacterial adhesion. The presence of surfactant tuned single bacterial adhesion by increasing the thickness of extracellular polymeric substances (EPS) and reducing the degree of EPS cross-linking. The adhesion kinetics and equilibrium state of bacteria attached to the surface confirmed the decrease in adhesion strength tuned by surfactants. The information obtained is valuable for understanding the interaction mechanism between a single bacterial cell and surface, developing new biofilm control strategies, and designing anticontamination materials. IMPORTANCE Studying the interfacial dynamic of single bacteria in complex environments is crucial for understanding the microbial biofilm formation process and developing antifouling materials. However, quantifying the interactions between microorganisms and surfaces in the presence of pollution at the single-cell level remains a great challenge. This paper presents the analysis of single bacterial interfacial behaviors modulated by surfactants and quantification of the adhesion strength via a plasmonic imaging technique. Our study provided insights into the mechanism of initial bacterial adhesion, facilitating our understanding of the adhesion process at the microscopic scale, and is of great value for controlling membrane fouling biofilm formation.