Beecroft Building, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Amit Singh, University of Warwick
Abstract
Living cells and tissues generate electric fields and fluid flows that play important roles in physiology. Both originate, in part, from ion transport across biological interfaces, including cell membranes and epithelial layers. In this talk, I will present an electrohydraulic framework that connects ion transport to electric fields, osmotic pressures, and fluid flows. I will show how spatially heterogeneous ion transport acts as a distributed current source, generating long-range electric fields, osmotic gradients, and fluid flows. A surprising result is that an externally applied electric field can be physically equivalent to an internal dipolar pattern of ion pumping, with both producing the same current and flow patterns. The resulting dipolar osmotic pressure can also drive self-propulsion through a mechanism distinct from classical electrophoresis and electroosmosis. I will then discuss how nonlinear electrohydraulic coupling can produce isotropic swelling of hollow epithelial structures, providing a possible explanation for recent experiments on epithelial organoids. Finally, I will show how feedback between ion transport and the resulting electric fields can destabilise symmetric states and generate spontaneous dipolar or multipolar patterns.