Frank Brown of the University of California, Santa Barbara is supported by an award from the Theoretical and Computational Chemistry program within the Division of Chemistry for the development of theoretical tools to 1) model lipid bilayers and biomembranes for use in simulating complex biochemical and biophysical phenomena and 2) to model single-molecule spectroscopy experiments with emphasis on photon counting measurements that provide both time and frequency domain resolution. Dr. Brown's Fourier-Space Brownian Dynamics (FSBD) algorithm allows hydrodynamically consistent modeling of inhomogeneous membrane surfaces over micron length scales at time scales of seconds or longer.
The research is having a broad impact on the interpretation of experiments that enhance our understanding of biological phenomena such as the diffusion of membrane proteins in crowded cellular environments or the structure and dynamics of human red blood cells. Dr. Brown communicates the excitement and importance of science to grade school children through his participation in the Physics Circus and Chemistry Outreach programs at UCSB.
This project is supported by the Theoretical and Computational Chemistry Program in a co-funding arrangement with Molecular Biophysics of Molecular and Cellular Biology.
NSF award 0848809 was used to carry out fundamental theoretical research related to understanding the structure and dynamics of lipid bilayer membranes and to interpreting experimental measurements carried out on lipid bilayer membranes. Specifically, new simulation methods were developed to study the advection and diffusion of lipids and proteins on the surface of membranes. Theoretical formulae were derived to enable the extraction of membrane viscosity from "domain flicker spectroscopy" experiments and the extraction of membrane bending moduli directly from "neutron spin echo" experiments. These formulae to interpret the experimental measurements have improved upon inaccurate methods of data analysis that were previously in use. A new theoretical framework was developed to analyze molecularly detailed simulations of lipid bilayer membranes. This work makes it possible for scientists that run large-scale computer simulations to compare their results with experimental measurements and should lead to improved computational models for cellular membranes. Nine graduate students and postdoctoral researchers were trained in the fields of theoretical chemistry and theoretical biophysics during their participation in the above research. The principal investigator of the award and one of his graduate students regularly participated in both the Physics Circus and Chemistry Outreach programs at the University of California, Santa Barbara. These programs demonstrate simple but visually exciting scientific principles to grade school students drawn from across Santa Barbara County. The aim of these programs is twofold. First, the children see that science can be interesting and exciting, perhaps for the first time in their lives. Second, students and their parents are exposed to the educational opportunities available at the University of California (UC). Many of the students from the agricultural regions of the county come from homes where neither parent has attended college and may never have set foot on a UC campus. A high percentage of these students are underrepresented minorities. These outreach efforts expose a diverse range of children to the UC system and show them that a college education is within their reach.
