Bacterial Chemotaxis

A PNAS publication from one of our customers used BioFlux for an assay to establish DMSO gradients over surface-attached P. aeruginosa under flow and measure single-cell chemotaxis during early biofilm development (Oliveira et al., 2016). (A) The BioFlux was used to produce a secure chemical diffusion gradient, consistently administering TB through one inlet while driving 350 mM DMSO and TB through the second inlet. C = C’/Cmax, C’ being the local concentration of DMSO, and Cmax being the concentration of TB and DMSO. (B) Increasing concentrations of DMSO over time altered motility. Cell trajectories with net movement in the -y direction are in red, whereas those with net movement in the +y direction are in blue. (C) The control displays that without DMSO, there is no preference of movement towards the y direction. (D and E) Graphical representations of the chemotactic bias show this (β represents the cell quantity moving in -y direction divided by quantity moving toward +y, grey line being the control, and black line being the presence of DMSO). (E) Over time, the surface became crowded, and the cell speed declined. (F) The kymograph shows the fluorescent intensity F of cells that expressed YFP (yellow fluorescent protein) in order to visualize the biofilm formations over time (red portion most concentrated with biofilms). (G) A 3D confocal micrograph shows the biofilm growth at t = 20 hours.