Bacterial Attachment Force Measurement

Bdellovibrio bacteriovorus is a Gram-negative predatory bacteria that shows promise as a potential antibacterial agent. B. bacteriovorus preys on other Gram-negative bacteria, the most notable of which is Escherichia coli. B. bacteriovorus has several distinct life stages. It first vigorously hunts for its prey, identifies it and attaches to it, then burrows into it, consuming it while reproducing inside it, before bursting out as multiple bacteria. This project investigates the attachment forces of B. bacteriovorus as it preys on E. coli. We do this using a highly focused laser beam, also known as an optical tweezer. We measure the trapping strength for a single B. bacteriovorus and then the force needed to pull it away from E. coli after it has attached. The trap strength is determined by the minimum distance the fluid surrounding the bacteria needs to be moved for the B. bacteriovorus to be freed from the trap. The results of this test show the strength of the optical trap relative to the size of the bacteria and its mobility. This project builds upon results obtained using traditional atomic force microscopy and shows that optical tweezers are a useful tool for examining B. bacteriovorus behaviors.