Self-organized canals enable long range directed material transport in a biofilm*

Long-range material transport is essential to maintain the physiological functions of multicellular organisms such as animals and plants. Here, we discover that a large-scale and temporally evolving channel system spontaneously develops in the bacterial colony. Fluid flows in the channels support the high-speed (up to 400 micron/s) transport of cells and outer-membrane vesicles, presumably driven by interfacial tension mediated by cell-secreted biosurfactants. Our findings present a unique form of the long-range directed material transport mechanism, advancing the understanding of multicellular microbial systems and suggesting a new principle to design patterns and functions of synthetic microbial communities.