Harvard WAM Seminars

Abstract
Mark Henle, UCLA (Chemistry & Biochemistry)


 
The Effects of Curvature and Topology on Membrane Hydrodynamics




The dynamics of mobile inclusions in lipid membranes are fundamental  to a variety of biological processes, including the aggregation of  proteins during cell-cell signaling and the coalescence of lipid raft  domains.  Additionally, elucidating the mobilities and hydrodynamic  interactions of colloidal particles at a fluid-fluid interface has  important technological ramifications on the formation of  colloidosomes.  In many of these applications, the membrane/interface  is a compact, strongly curved structure.  In this talk, I will explore  the effects of curvature and topology on the hydrodynamics and  transport properties of membranes.  In particular, I will consider the  motion of point-like and extended (rod-like) objects in a spherical  membrane.  The results indicate that the topology and curvature of a  membrane can indeed have a strong effect on its transport properties:   First, the topology of the sphere fundamentally alters the nature of  the membrane velocity field by forcing the existence of singularities  (e.g. vortices, sources, sinks) in this field;  in addition, the  curvature of the membrane can suppress the diffusion of objects  embedded therein.  Finally, I will show that this theoretical model  agrees quantitatively with recent experimental measurements by A.D.  Dinsmore and co-workers (University of Massachusetts, Amherst) on the  motion of a rod bound to the crowded interface of a water-in-oil  droplet.

 

Harvard School of Engineering and Applied Sciences