Prof. Mrityunjay Kothari from the University of New Hampshire will be giving a talk in the ME Auditorium tomorrow, Wednesday 8th January from 16:30-17:30. The details of the talk are given below.

Title: The crucial role of elasticity in regulating liquid-liquid phase separation in cells

Venue: ME Auditorium, 16:30-17:30, 8th January.

Abstract: Liquid-liquid phase separation (LLPS) — an instability that causes a liquid mixture to separate into two or more distinct phases — has recently emerged as a fundamental mechanism underlying the formation of many membraneless organelles in cells. In the current literature, LLPS is studied considering the cellular milieu as simply a mixture of fluids. However, cells are more complicated than that — they are better described as an elastic network that is permeated by fluid mixture, giving them both solid- and liquid-like properties. Despite our understanding of the elastic behavior of cells as a whole, the role of elasticity in the process of LLPS has not received much attention and remains poorly understood. Analogous problem from materials science literature (formation of precipitates in metallic alloys) hints that elasticity will significantly affect the onset and the outcome of phase separation, such as the shape, size and transport dynamics of liquid droplets.
 

In this talk, I will discuss our work on modeling the role of elasticity in LLPS and the ensuing
dynamics. We combine recent experimental data with theoretical predictions that capture the
subtleties of nonlinear elasticity and fluid transport. We show that within the biologically
accessible range of material parameters, cellular systems are highly sensitive to elastic properties and can potentially use this mechanism as a mechanical switch to rapidly transition between different states. Furthermore, we show that this active mechanically mediated mechanism can drive transport across cells at biologically relevant timescales and could play a crucial role in promoting spatial localization of condensates; whether cells exploit such mechanisms for transport of their constituents, remains an open question.
 

The theory presented is applicable beyond cells — relevant physical systems consisting of an
elastic medium permeated by fluid mixture are ubiquitous, with examples ranging from foods
(think of breads as CO2 bubbles in a network of gluten protein) to gas-laden sediments to soft
composite materials.
 

Bio: Mrityunjay Kothari is an Assistant Professor in the Department of Mechanical Engineering at the University of New Hampshire (Durham, NH, USA). In his past life he was a Postdoctoral
Associate in Civil and Environmental Engineering at MIT, and, briefly, in the School of
Engineering at Brown University. Dr. Kothari has a Ph.D. and Sc.M. in Solid Mechanics from
Brown University, where he was the recipient of the 'Outstanding Dissertation Award' in the
School of Engineering. He has a Bachelors degree in Mechanical Engineering from Indian
Institute of Technology Kanpur. His current research interests lie in the multi-physics mechanics of materials, with the goal of understanding how materials respond to complex real-world environments, how multi-physics couplings can be applied towards the design of better materials, and how biological systems — multi-physics by their very nature — take advantage of these couplings in their functioning. He integrates experimental methods with tools and techniques from solid mechanics, materials science, polymer physics, soft matter, and applied mathematics in pursuit of these goals. Dr. Kothari's research on graphene has already enabled advances for the next generation of DNA sequencing.