Microscale confinement features can affect biofilm formation

The majority of bacteria in nature live in biofilms, where they are encased by extracellular polymeric substances (EPS) and adhere to various surfaces and interfaces. Investigating the process of biofilm formation is critical for advancing our understanding of microbes in their most common mode of living. Despite progress in characterizing the effect of various environmental factors on biofilm formation, work remains to be done in the realm of exploring the inter-relationship between hydrodynamics, microbial adhesion and biofilm growth. We investigate the impact of secondary flow structures, which are created due to semi-confined features in a microfluidic device, on biofilm formation of Shewanella oneidensis MR-1. Secondary flows are important in many natural and artificial systems, but few studies have investigated their role in biofilm formation. To direct secondary flows in the creeping flow regime, where the Reynolds number is low, we flow microbe-laden culture through microscale confinement features. We demonstrate that these confinement features can result in pronounced changes in biofilm dynamics as a function of the fluid flow rate