Biological and Biomedical Physics
Biological Physics has been a significant research concentration within the Physics Department for more than 15 years. Seven faculty have active research programs in biological or on medical physics. Highlights of the program include:
- Research on multiple levels from molecular (DNA, proteins) to tissue (heart muscle, brain)
- National and international collaborations
- Undergraduate Biomedical Physics program
- Biological physics seminar series sponsored by the Center for Interdisciplinary Research Center (CIRCS)
- Clinical applications of biomedical physics are taught via junior and senior level seminar courses in medical imaging, medical applications of lasters and optical techniques, and radiation therapy, given by expert practictioners from local hospitals and biotechnology companies
- Singular Molecule DNA-Protein Interactions
Force
spectroscopy measurements in the laboratory of Professor
Mark Williams use optical tweezers to manipulate single
molecules and measure the forces required to stretch
them. Measurements of these forces are used to determine
the stability of the DNA double helix and the extent
to which various DNA binding proteins alter the structure
and stability of DNA. This approach provides unique
insights into the function of these proteins in the
cell.- Biological Metallodynamics
Nuclear
resonance vibrational spectroscopy (NRVS) reveals
low frequency Fe vibrations that participate in biological
reactions, on the basis of synchrotron measurements
near the 14.4 keV Mössbauer resonance. This work
is done by the group of Professor Tim Sage in collaboration
with Wolfgang Sturhahn and Ercan Alp at the Advanced
Photon Source and Professor Steve Durbin at Purdue
University.- Infrared Crystallography
- Polarized
infrared measurements in the laboratory of Professor
Tim Sage yield precise molecular orientations and
connect structural models derived from X-ray diffraction
with conformational dynamics under physiological conditions.
Femtosecond
coherence spectroscopy measurements in the laboratory
of Professor Paul Champion use ultrafast lasers to probe
the "big bang" of biophysics, the first picosecond
of diatomic ligand binding reactions in heme proteins.
Direct measurements of coherent protein oscillations
and vibration population decay (cooling) are performed
using state-of-the-art laser technology. Longer time-scale
biological processes (including a variety of novel proteins
in aqueous equilibrium states or embedded in biological
membranes) are probed with more conventional methodology
(e.g., optical absorption and resonance Raman spectroscopy).
The research in Professor Alain Karma's group is aimed at understanding the physiological origin and complex nonlinear dynamics of irregular heart rhythms through the development of mathematical models and computer simulations. Ongoing projects focus on modeling the bidirectional coupling of the intracellular calcium and electrical systems at the single cell level and the initiation and maintenance of the electrical turbulence underlying ventricular fibrillation at the organ level.
The primary goal of Professor Armen Stepanyants' group is to understand the principles governing synaptic connectivity in the mammalian brain. Among several fundamental questions studied are: how do neurons find appropriate synaptic targets in the course of development, and how do neuron circuits change during learning and memory? What is the connectivity diagram in the adult cortical column? Is there an optimization principle which accounts for the design and the evolution of the cortex?
The Biological Physics faculty includes Professors Ronald Aaron (Emeritus), Albert-László Barabási, Paul Champion, Alain Karma, Lev Perelman, J. Timothy Sage, Carl Shiffman (Emeritus), Armen Stepanyants, and Mark Williams.