Microswimming navigation in temperature and viscosity gradients

The proposed project is for undertaking a research on eukaryotic and prokaryotic unicellular motility (e.g. bacteria, green algae, sperm cells) in external temperature and viscosity gradients. It has been known that swimming cells respond to temperature changes and follow temperature gradients, which affects the population density redistribution, biofilm formation, infection control. For the sperm cells, the viscosity and temperature gradients have been regarded as important guiding cues in fertilisation success. Temperature, apart from being an external signal which can be sensed by swimming cells through specific receptors, also alters properties of the environment, such as viscosity or pH. This makes problems of thermo- and visco- taxes intrinsically linked. Despite the well-established phenomena of cells thermotaxis [1], the details and mechanisms of the process remain unclear. Viscotaxis though has been barely studied [2]. The challenge of the project is to understand cell's dynamic response on microscopic and population levels to the temperature and viscosity variations. The research will involve multiscale measurements of individual swimming cells and ensemble behaviour in controlled microfluidic environment, as well as mathematical modelling of the population dynamics applying identified microscopic mechanisms of motion for individual swimmers. The student will to learn and apply a wide range of experimental analytical techniques, such as soft lithography, microfluidics, video-microscopy, molecular and micro-biology methods, image processing techniques, Brownian dynamics simulations etc. throughout the research. The potential impact can be seen in designing novel concepts for preventing biofouling, and improvement of artificial insemination techniques.

References
[1] M. R. Clegg et al. Eur. J. Phycol., 38, 195 (2003); H. Salman, A. Libchaber, Nature Cell Biology 9, 1098 (2007).
[2] M.Yu. Sherman, et al. FEMS Microbiology Letters 13, 137 (1982)

EPSRC
The project is aligned within EPSRC research area 'Biophysics and soft matter physics', as the problem of interest ranges across biological length scales and relates it to understanding biological systems.

Industrial and academic partners
The project involves industrial and academic partners across the UK:
Prof. Allan Pacey, University of Sheffield
Bourn Hall Clinic
Genus Breeding Inc