An assessment of the dynamic stability of microorganisms on patterned surfaces in relation to biofouling control.

Microstructure-based patterned surfaces with antifouling capabilities against a wide range of organisms are yet to be optimised. Several studies have shown that microtopographic features affect the settlement and the early stages of biofilm formation of microorganisms. It is speculated that the fluctuating stress-strain rates developed on patterned surfaces disrupt the stability of microorganisms. This study investigated the dynamic interactions of a motile bacterium (Escherichia coli) with microtopographies in relation to initial settlement. The trajectories of E. coli across a patterned surface of a microwell array within a microchannel-based flow cell system were assessed experimentally with a time-lapse imaging module. The microwell array was composed of 256 circular wells, each with diameter 10 μm, spacing 7 μm and depth 5 μm. The dynamics of E. coli over microwell-based patterned surfaces were compared with those over plain surfaces and an increased velocity of cell bodies was observed in the case of patterned surfaces. The experimental results were further verified and supported by computational fluid dynamic simulations. Finally, it was stated that the nature of solid boundaries and the associated microfluidic conditions play key roles in determining the dynamic stability of motile bacteria in the close vicinity over surfaces.