Active control of bacteria swimming orientation in a liquid crystal matrix by using UV light

Abstract

Bacteria are omnipresent in nature. They also play a key role in biomedical industry and new technologies. A capability to control their movement may be very useful both for their study and applications. Here we explore the possibility of such active control of the movement of flagellated bacteria (a bacterium that can swim thanks to the rotation of its long screw-like helix). We demonstrate that we can dynamically change the swimming direction of bacteria by incorporating them into a liquid crystal media where the phase transition is locally controlled by UV illumination. This work opens new avenues to develop lab-on-a-chip devices that could be used as a micro-farm to “harvest” and study bacteria.

Keywords:

• Bacteria
• lab-on-a-chip
• liquid crystals

Aknowledgements

We acknowledge the financial support of the Natural Sciences and Engineering Research Council of Canada. T.G. thanks Canada Research Chair in Liquid Crystals and Behavioral Biophotonics as well as Manning Innovation and INO-CAP foundations for their support. We are grateful to Louis-Philippe Robichaud and Dr. A. Tork (from LensVector and TLCL Optical Research Inc.) for their help during our experiments and to the group of H.C. Berg for bacterial strains.