Surface patterning of biofilm: A toolbox study to detect microbial metabolites

Surface patterning of bacterial biofilm provides an opportunity to understand the microbial metabolic exchange between bacterial species. By using various techniques, one can put different bacterial species in close proximity and study their interaction by using various assay kits and analytical techniques. In this study, surface patterning of Pseudomonas aeruginosa was performed by electrochemical codeposition of bacteria and alginate gel. P. aeruginosa are mainly grown on health care equipment and cause infections, therefore it is important to understand their virulence during biofilm growth. P. aeruginosa produces quorum sensing molecules known as PQS and phenazines. Phenazines are redox active and therefore can be detected using electrochemistry. To detect phenazines, a 30 µm carbon fiber electrode was fabricated. The electrode has a detection limit of 1µM to 5µM PYO, determined by recording Square wave voltammetry in various concentrations of PYO in 10 mM PBS. To verify trapping of live bacteria inside the gel, confocal microscopy was used to record 3D images with the model system: gfp tagged Escherichia coli–alginate gel. In the future, we plan to use Scanning Electrochemical Microscopy (SECM) with carbon fiber ultra-micro sensor to determine the distance between two bacteria species required to trigger quorum sensing