Biological Physics-Dept of Physics - Carnegie Mellon University

Biological Physics

Faculty

Markus Deserno (Group website)
Alex Evilevitch
Steve Garoff (Group website)
Mathias Lösche (Group website)

John Nagle (Group website)
Robert Swendsen
Michael Widom
Stephanie Tristram-Nagle
Mohammad Islam (Courtesy)

Maumita Mandal

Frank Heinrich


Group Website:   http://www.cmu.edu/biolphys

Group Overview

Biological Physics is one of the most exciting frontiers in physics today. In this field, we investigate the mechanisms by which complex biological molecules and assemblies operate. At the same time, bio-related phenomena offer the physicist unique opportunities to learn new physics on elegant, complex systems.

Problems currently under study at Carnegie Mellon include the structure of lipid bilayers, the physics of viruses, the folding of proteins and the three-dimensional structure of cells. In these studies, we use the entire spectrum of tools from experimental over theoretical to computational, including: x-ray and neutron scattering, optical microscopy and single-molecule spectroscopy, statistical thermodynamics, field theory, differential geometry, and Monte Carlo and molecular dynamics simulations.

Member Research Thrusts

Deserno uses both theoretical and computational techniques to study lipid membranes. On the theoretical side, a continuum elastic description is used, and on the computational side, coarse-grained simulations in which the physical system is not represented in atomic detail are utilized. This renouncement of chemical resolution allows one to study much larger systems on much longer time scales and to access a new arena for physical questions, many of which turn out to have biological significance.

Evilevitch's physical virology group investigates fundamental physical principles that control viral encapsidation and genome release. Our group has discovered a way to determine genome pressure in viral capsid and found that to be as high as 40 atm in bacteriophage lambda, a pressure equivalent to that at a depth of 1200 ft in the ocean. We are specifically interested in determining the physical nature of genome packaging, the kinds of pressures involved, the strengths and elastic properties of the capsids, and limits on the amount of material that can be encapsidated. The main tools in the lab are: Atomic Force Microscopy (AFM), microcalorimetry, and high resolution cryo electron microscopy.

Garoff and collaborators are noted for their ground-breaking research in anisotropic fluids and their surface properties and have recently developed a research agenda that originated from this expertise and overlaps strongly with Biological and Medical Physics.

Lösche has developed biomimetic membrane systems, such as tethered bilayer membranes (tBLMs), with well-controlled molecular architectures and superior performance characteristics, which take center stage in fundamental studies of pathogen interactions with membranes. Objects of study range from membrane-mediated viral assembly to amyloids and structural filaments, such as the nuclear lamina.

Nagle, Tristram-Nagle and collaborators have developed a new x-ray method that exploits the diffuse scattering of x-rays to obtain the structure along the out-of-plane direction of the most biologically relevant fully hydrated bilayers in their fluid thermodynamic phases. Having recently published the highest spatial resolution structures of such one-component bilayers, studies of lipid mixtures and mixed lipid/peptide systems are now underway.

Widom applies classical mechanics and statistical mechanics to model the mechanical properties of viral capsids and to elucidate the structure and function of RNA molecules.