Article

Biomedical Microdevices

, Volume 12, Issue 3, pp 499-503

An automatic microturbidostat for bacterial culture at constant density

  • Xianjia LuoAffiliated withCenter for Microfluidics and Nanotechnology and School of Physics, The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking UniversityEcole Normale Superieure, CNRS-ENS-UPMC UMR 8640
  • , Kangyang ShenAffiliated withCenter for Microfluidics and Nanotechnology and School of Physics, The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University
  • , Chunxiong LuoAffiliated withCenter for Microfluidics and Nanotechnology and School of Physics, The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking UniversityCenter for Theoretical Biology, Academy for Advanced Interdisciplinary Studies, Peking University Email author 
  • , Hang JiAffiliated withCenter for Microfluidics and Nanotechnology and School of Physics, The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University
  • , Qi OuyangAffiliated withCenter for Microfluidics and Nanotechnology and School of Physics, The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking UniversityCenter for Theoretical Biology, Academy for Advanced Interdisciplinary Studies, Peking University
  • , Yong ChenAffiliated withCenter for Microfluidics and Nanotechnology and School of Physics, The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking UniversityEcole Normale Superieure, CNRS-ENS-UPMC UMR 8640 Email author 

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Abstract

We have developed a microturbidostat for long time bacterial culture at constant density controlled by optical detection and integrated pneumatic valves. The device was fabricated by multilayer soft lithography and in-situ formation of an agarose filter. The culture chamber of bacteria was connected in one side to a single bacterial input-output channel and in another side to a nutrient channel in which the agarose filter was formed to ensure the diffusion of nutrients and metabolites without bacterial loss. The bacterial number in the culture chamber was determined by measuring the fluorescence intensity of GFP proteins of the bacteria and the redundant bacteria could be exported automatically through the input-output channel with integrated micro-valves. In order to optimize the operation performance, we investigated the bacterial exportation efficiency with different input-output channel widths. As expected, the bacterial sorting coefficient was proportional to the input-output channel width. The results also showed that with a 20 µm channel-width, a long time culture was possible with a constant bacterial number in the chamber in the range from 400 to 700.

Keywords

Microfluidics Microturbidostat Bacterial growth