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Sunday, November 23, 2014

Collective flow dynamics across a bacterial carpet: Understanding the forces generated

Yi-Teng Hsiao, Jing-Hui Wang, Kuan-Ting Wu, Jengjan Tsai, Cheng-Hung Chang and Wei-Yen Woon

Bacterial carpets consist of randomly anchored uni-polar-flagellated sodium-motive bacterial matrix are prepared by flow deposition. Collective flow dynamics across the bacterial carpets are probed with optical tweezers-microsphere assay. Around the center of a uniform bacterial cluster, collective forces that pull microsphere towards carpet surface are detected at a distance of 10 μm away from carpets. At sodium-motive driving over a critical value, the force magnitudes increase abruptly, suggesting a threshold-like transition of hydrodynamic synchronization across bacterial carpet. The abrupt force increase is explained in term of bifurcation to phase synchronization in a noisy non-linearly coupled rotor array mediated by hydrodynamic interactions.

DOI

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