Dynamics of bacterial motility and chemotaxis toward localized sources under flow in porous media

We study the combined effects of bacterial behavior, hydrodynamics, and porous medium heterogeneity on microbial transport and nutrient sensing. To do this, we created a microfluidic platform that uses hydrogels as steady, localized nutrient sources. This system allows real-time control of chemical gradients and provides direct optical access for simultaneous observation of bacterial movement and fluid flow. Using this platform, we explore how bacterial traits—specifically motility and chemotaxis—affect nutrient exposure and cell transport across different flow regimes and spatial heterogeneities. Our findings show that the structure of the porous medium significantly influences nutrient access, and that the advantages of motility and chemotaxis depend on the flow conditions and the spatial arrangement of chemical signals.