Chemical Sensing via Chemotaxis of Euglena gracilis Confined in an Isolated Micro-Aquarium

Abstract:

On-chip cytotoxicity sensing for liquid substances was investigated by using the microbial chemotaxis of Euglena gracilis. The Euglena cells were confined in a closed-type micro-aquarium in a PDMS microchip, and the micro-aquarium was isolated from two microchannels to flow test and reference liquid substances. Small molecules of liquids permeated into PDMS and diffused into the water in the micro-aquarium, and thus, the chemical concentration gradient of test liquids was built in the micro-aquarium. The negative chemotactic movements of Euglena cells were observed for ethanol down to 0.5% within 2-5 min after the injection of diluted ethanol into one of the separated microchannels (counter reference = pure water). On the other hand, when 0.5% H₂O₂ was introduced as a test liquid (counter reference = pure water), the Euglena cells fell into continuous rotation instead of single step turning and/or straight forward swimming. As a result, total swimming activity in the micro-aquarium decreased even after H₂O₂ flow was switched back to water. The observation shows that the types of cytotoxic effects can be identified through the cell movement analysis.

• Periodical: Key Engineering Materials (Volume 605)
• Pages: 95-98
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.605.95
• Online since: April 2014
• Authors: Kazunari Ozasa*, Jee Soo Lee, Simon Song, Masahiko Hara, Mizuo Maeda
• Keywords: Bacteria, Chemical Sensing, Chemotaxis, Euglena gracilis, Micro-Channel, PDMS

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