Bacterial scattering in microfluidic crystal flows reveals giant active Taylor–Aris dispersion

• DOI: 10.1073/pnas.1819613116
• Publication Date: 2019-05-17T00:25:49Z
• Authors: Amin Dehkharghani; Nicolas Waisbord; Jörn Dunkel; Jeffrey S. Guasto
• Keywords: Bacteria; Movement; Microfluidics; Bacterial Physiological Phenomena; Models, Biological; 01 natural sciences; Physical Phenomena; 13. Climate action; Biofilms; 0103 physical sciences; Hydrodynamics; 14. Life underwater; Porosity; Ecosystem

Significance The fluid habitats of swimming microbes are characterized by heterogeneous flow, typical of groundwater and marine turbulence, which can augment cell transport in unexpected ways and affect important processes ranging from biogeochemical cycling to disease transmission. Following in the footsteps of century-old light diffraction techniques, the scattering of bacteria in microfluidic crystal flows reveals how cell shape and motility couple to hydrodynamic gradients, giving rise to observed filamentous cell density patterns. Consequently, hindered bacterial mobility transverse to the flow greatly enhances downstream dispersal. These results illustrate the stark contrast of active matter transport with passive Brownian particles and may provide insights into microbial ecosystems, biomedical device design, and the guidance of swimming microrobots.