Surface plasmon resonance imaging (SPRi) for multiplexed evaluation of bacterial adhesion onto surface coatings

Surface plasmon resonance imaging (SPRi) provides continuous, label-free, high-spatial-resolution monitoring of physical changes that occur on surfaces that are up to one square centimeter in area. Here, we utilize SPRi technology to address the challenge of quantitatively evaluating the efficacy of multiple materials to prevent biofilm formation when exposed to flowing fluids. A multiplexed analysis format is particularly important in bacterial attachment studies as adhesion events are very sensitive to their local micro-environment, which are difficult to reproduce and control between experiments. In this study, the effectiveness of bovine serum albumin (BSA), casein, and penicillin/streptomycin surface coatings to prevent Pseudomonas aeruginosa and Staphylococcus aureus adhesion is investigated with SPRi. The coatings were deposited on different sections of a single gold SPRi sensing surface and monitored for 24 hours while being exposed to a continuous flow of growth medium containing bacterial cells. We found that casein most effectively inhibits attachment of cells to the gold surface over a 24 hour period, with an 80% decrease in adhesion versus a bare gold surface for P. aeruginosa and a 60% decrease for S. aureus.