A wall of funnels concentrates swimming bacteria

Peter Galajda, Juan Keymer, Paul Chaikin, Robert Austin

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Randomly moving but self-propelled agents, such as Escherichia coli bacteria, are expected to fill a volume homogeneously. However, we show that when a population of bacteria is exposed to a microfabricated wall of funnel-shaped openings, the random motion of bacteria through the openings is rectified by tracking (trapping) of the swimming bacteria along the funnel wall. This leads to a buildup of the concentration of swimming cells on the narrow opening side of the funnel wall but no concentration of nonswimming cells. Similarly, we show that a series of such funnel walls functions as a multistage pump and can increase the concentration of motile bacteria exponentially with the number of walls. The funnel wall can be arranged along arbitrary shapes and cause the bacteria to form well-defined patterns. The funnel effect may also have implications on the transport and distribution of motile microorganisms in irregular confined environments, such as porous media, wet soil, or biological tissue, or act as a selection pressure in evolution experiments.

    Original languageEnglish (US)
    Pages (from-to)8704-8707
    Number of pages4
    JournalJournal of bacteriology
    Volume189
    Issue number23
    DOIs
    StatePublished - Dec 2007

    ASJC Scopus subject areas

    • Microbiology
    • Molecular Biology

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