CBE Seminar Series: Wilson Poon, University of Edinburgh

Description

Soft matter physics and the COVID-19 pandemic Much of the science underpinning the global response to the COVID-19 pandemic lies in the soft matter domain. Coronaviruses are composite particles with a core of nucleic acids complexed to proteins surrounded by a protein-studded lipid bilayer shell. A dominant route for transmission is via air-borne aerosols and droplets. Viral interaction with polymeric body fluids, particularly mucus, and cell membranes controls their infectivity, while their interaction with skin and artificial surfaces underpins cleaning and disinfection and the efficacy of masks and other personal protective equipment. The global response to COVID-19 has highlighted gaps in the soft matter knowledge base. I will survey these gaps, especially as pertaining to the transmission of the disease, and suggest questions that can (and need to) be tackled, both in response to COVID-19 and to better prepare for future viral pandemics. Biography: Wilson Poon trained in physics at Cambridge, where he obtained both of his degrees. After a year at Portsmouth Polytechnic, he moved to Edinburgh in 1990, where he now holds the Chair of Natural Philosophy, and divides his research effort between complex fluids and the biophysics of microorganisms, especially bacteria. Much of Poon's work is inspired by problems originating in industry. For example, his recent experimental breakthrough in demonstrating the key role of frictional contacts in the flow of non-Brownian suspensions has partly arisen from working on the manufacture of chocolate and (separately!) ceramics and spotting similarities across these two sectors; the chocolate work has attracted significant media attention, including the New York Times. In microorganisms, Poon’s experiments using well-characterised swimming E. coli bacteria has helped establish the field of ‘active suspensions’ by providing clean data with which to challenge theory and simulations. For example, his group has used specially-constructed bacterial strains with light-activated swimming to verify a fundamental theorem stating that the product of local (number) density and swimming speed should be constant across a whole population. The same organisms have been used to demonstrate a method for ‘painting’ dynamical pictures using bacteria. Poon’s achievements have been recognised by his election to the national academy of Scotland, the Royal Society of Edinburgh, in 2004, and the award of the Sam Edwards Medal by the Institute of Physics in 2019. Outside physics, he also researches and teaches the relation between science and religion, and is writing a book on one of the most beautiful medieval manuscripts in public ownership in Scotland (a 15th century ‘book of hours’).