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Wilson POON

Résumé :

A bacterium is the smallest ’quantum’ of autonomous living matter. Their physical dimensions mean that they are colloids. But they are ’active colloids’ in that they transduce free energy from their environment, and use the energy to engage in intrinsically non-equilibrium activities such as growth and self-propelled motion (’swim’). Until now, the biophysical study of bacteria has concentrated on intra-cellular processes. In this talk, I will introduce an emerging field of biophysics in which the focus of attention is on whole bacterial cells considered as active colloidal particles ; experimental methods and theoretical ideas from soft matter physics are then used to give insights into the behaviour of single cells (e.g. how they swim in magnetic fields) and of multiple cells (e.g. the shape of colonies and the mode of aggregation). Experiments using well-characterised bacteria in turn show new phenomena not previously seen in passive colloids. Accounting for these phenomena satisfactorily will need fundamental advances in statistical mechanics.

Biographie :

Wilson Poon was born in Hong Kong, and moved to Britain at the age of 17 to study. He did his undergrad and postgrad physics degrees in Cambridge, the latter on the high temperature phase transitions of minerals. After a year teaching at Portsmouth Polytechnic, he moved to Edinburgh as a lecturer in solid state physics. When Peter Pusey joined the department in 1992 he moved into soft matter physics, and has been working on colloids since. Over the last 5 years he has held an Engineering and Physical Sciences Research Council (EPSRC) Senior Research Fellowship, which released him from teaching to concentrate on his research. This enabled him to develop a new line of work studying bacteria as active colloids. In 2004 de was elected to be a Fellow of the Royal Society of Edinburgh, which is Scotland’s national academy of the arts and sciences.

Contact :

Wilson Poon
Institute for Condensed Matter and Complex Systems
School of Physics & Astronomy
University of Edinburgh