Single Cells of Pseudomonas aeruginosa Exhibit Electrotaxis and Durotaxis Behaviours

Pseudomonas aeruginosa is frequently associated with nosocomial infections, including polymicrobial wound infections and the complex biofilm communities that reside within the cystic fibrosis lung. P. aeruginosa utilizes flagellum-mediated motility to approach, attach to, and spread across a surface using a combination of swimming, swarming and twitching (type IV pili extension and retraction) motility. We report an innovative approach to study the motility of single P. aeruginosa cells in microfluidic channels possessing different structural geometry, all with the flexibility of being able to manipulate stiffness gradients and electric fields to investigate changes in motility in response to specific stimuli. P. aeruginosa cells exhibit restricted motility in reduced microchannel spaces, with preferential migration toward a stiffer region in a rigidness gradient of substrate medium and preferential migration toward a positive electrode in presence of a pulsed or successive electric field. This single-cue environmental study using microfluidic technology lays the groundwork for multi-cue experimentation to more faithfully mimic conditions in vivo, demonstrating just some of the advantages of this technique. This study is designed to examine the interplay between surface rigidity, mechanical, and electrical cues to pave the way for improvements in the design of anti-fouling surfaces for biomedical applications and to identify new ways to inhibit bacterial biofilm growth through motility restriction.