We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Institute of Advanced Study

Professor Robert Walker

IAS Fellow at Van Mildert College, Durham University (January - March 2007)

Professor Walker is an associate professor of chemistry at the University of Maryland, College Park, (USA) where he also serves as the associate chair of the university's Chemical Physics Program. His research program uses a variety of nonlinear optical methods to examine molecular structure and chemical properties of liquid interfaces including liquid/solid, liquid/liquid, and liquid/vapor systems. Of particular interest is how properties associated with bulk solvation change across these different surfaces. To measure the width of different liquid surfaces, Professor Walker's research group designed novel families of surfactants - dubbed "molecular rulers" - that vary systematically the location of chemical probes relative to nominal interfacial boundaries. This work was first featured in Nature (Vol. 424, pp. 296-299, (2003)) and has led to more than ten publications in peer-reviewed journals during the past three years. Other active areas of research in the Professor Walker's research group include spectroscopic studies of fuel oxidation in high temperature solid-oxide fuel cells and molecular organization in model membrane systems.

Professor Walker has received a number of awards recognizing his research accomplishments, including an CAREER Award from the National Science Foundation (USA) and a Alfred P. Sloan Research Fellowship

Whilst at the IAS, Professor Walker will collaborate closely with chemists at Durham to examine the fluidity, phase separation, and other properties of mixed supported lipid bilayers. At a fundamental level these studies will provide direct evidence of how symmetric and asymmetric biological species organize in two dimensions. Experiments examining bilayer stability will speak directly to questions about mechanisms of membrane failure and cell death.

IAS Fellow's Public Lecture - Where Species Begin: Observations about Cell Membranes and What We Can Do About It

8th March 2007, 17:30 to 18:30, The Ustinov Room, Van Mildert College

A common denominator to all living species is the cell membrane. Cell membranes are designed to keep the tools necessary for life processes contained and separated from harmful threats that can appear in local surroundings. Despite the wide variety in cell types - liver, skin, neural, etc. - most cell membranes share remarkably similar composition, not only within a single organism but across species in general. A functioning cell membrane regulates the passage of nutrients and waste into and out of cells. When membrane structure changes, so too does cell function. Changes in membrane structure have been tied directly to diseases as diverse as Alzheimer's and diabetes. This talk will discuss the role of membranes, explore what we know about membrane structure and function, and identify salient questions related to the molecular organization found within membranes. Highlighted will be strategies intended to answer these questions so that we may develop a more comprehensive, predictive understanding of these complex biological systems.

Professor Robert Walker Publications

Walker, R., Pomfret, M.B., Marda, J., Jackson, G.S., Eichhorn, B.W., and Dean, A.M. (2008) 'Hydrocarbon Fuels in Solid Oxide Fuel Cells: In Situ Raman Studies of Graphite Formation and Oxidation' in J. Phys. Chem. C, 112(13), pp5232-5240.

Walker, R., Can, S.Z., Chang, C.F. (2008) 'Spontaneous formation of DPPC monolayers at aqueous/vapor interfaces and the impact of charged surfactants' in Biochimica et Biophysica Acta, pp2368-2377.

IAS Insights Paper


All living organisms consist of cells, regardless of whether the organism is a simple, single cell bacterium or a highly-evolved mammal containing up to 1012 highly specialized cells performing individualized, well-defined functions. Cell boundaries are defined by cell membranes. These barriers serve to contain and protect cell components from the surroundings as well as regulate the transport of material into and out of the cell. Cell membranes all share a similar bilayer architecture, although the details of membrane composition can vary greatly, from organism to organism and even for different types of cells within the same organism. The origins and purposes of this compositional complexity remain a mystery. This paper examines some of the common denominators shared by (mammalian) cell membranes with particular attention focused on phospholipids, a membrane's primary building blocks. One goal is to emphasize some of the many unresolved questions about how phospholipids organize themselves in cell membranes to provide specific functional behavior and about how slight variation in phospholipid composition affects membrane properties.

Insights Paper