Investigating Bacterial Detachment on Polymeric Biomaterial Nanopillared Surfaces Under Shear Stress

Pseudomonas aeruginosa is an opportunistic biofilm forming bacterium that exhibits the ability to twitch upstream in fluid flow environments. The upstream movement is facilitated by the retraction and extension of their type iv pili mechanosensor ATPase motors pilT and pilU when adhered to a surface. Here, motility prohibition and detachment of P. aeruginosa are studied on polymer biomaterial surfaces structures with arrays of nanopillared geometries under fluid flow. The arrays of nanopillars range in periodicity from 200, 300, to 600 nanometers. Upstream movement direction, detachment, and velocity of wild-type P. aeruginosa expressing GFP were monitored in flow channels of flat and nanopillared surfaces and quantified using fluorescence microscopy. The cell motility prohibition and detachment under shear stress was observed to have a nanopillar surfaced periodicity dependence. This bacteria-biomaterial interaction allows us to design our surface interfaces with specific nanopillared geometries for structurally controlling cell motility and detachment under fluid flow. The disruption of surface attached bacterium upstream movement that lead to colonization and biofilm formation is crucial in preventing harmful infection from contaminated medical devices such as catheters.