Microfluidic gas/liquid toxicity sensing through the chemotaxis of euglena cells confined in a micro-aquarium

Abstract

We developed a new biosensor device for environmental gas/liquid toxicity sensing, which utilizes the chemotaxis of microbial cells confined in a micro-aquarium. The device has an isolated micro-aquarium to confine microbial cells separately from flowing gas/liquid in two bypass microchannels, and the molecules of the flowing gas/liquid permeate from the microchannels into the micro-aquarium through porous poly-dimethylsiloxane (PDMS) walls. We demonstrate that CO2-gas or ethanol liquid can be sensed by the device through the chemotaxis of Euglena gracilis. Since Euglena cells in the device can be maintained for more than two weeks, our chemotaxis device is suitable for long-term toxicity monitoring of environmental gases/liquids as well as for microbiological study on chemotactic reactions of motile microbes.