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LABORATORY
OF INTEGRATIVE AND MEDICAL BIOPHYSICS
Ralph
Nossal, PhD, Chief The
Laboratory of Integrative and Medical Biophysics (LIMB) performs
cross-disciplinary research leading to deeper understanding of cell and
tissue processes in both normal and disease states. It also develops new
methodologies for biomedical research and diagnosis. The LIMB’s work
links biomedical research with experimental and theoretical techniques
commonly associated with research in the physical and engineering sciences.
Specialized interests and expertise extend to optical imaging of biological
tissues, magnetic resonance imaging, mathematical modeling, methods of
quantitative cell biology, techniques for assessing ultra-small biological
samples, and polymer physics and physical chemistry. The laboratory’s
capabilities include advanced physical methods such as diffuse optical
tomography, magnetic resonance imaging, neutron scattering, fluorescence
correlation spectroscopy, and an ability to formulate mathematical and
computational models. Investigators study biological function at levels of
complexity varying from molecule to tissue, focusing on interactive behavior
at different length and time scales. Much of the LIMB’s work is
strongly collaborative, and a number of research projects are carried out
with colleagues in other NIH branches and laboratories as well as with
investigators at other institutions. Peter Basser heads the Section
on Tissue Biophysics and Biomimetics, which seeks to understand
fundamental relationships between function and structure in soft tissues, in
“engineered” tissue constructs and in tissue analogs (e.g.,
polymer gels). In combination with descriptive biological analysis, members
of the section develop new physical theories, mathematical and computational
models, and biomimetic tissue analogs to aid in the design and interpretation
of biological experiments. The section also continues its development of
Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) as a probe of tissue
structure in normal or diseased organs, with particular emphasis on
developing quantitative methods for improving resolution and specificity in
applications involving brain and other soft tissues. Led
by Robert Bonner, the
Section on Medical Biophysics focuses on interdisciplinary
translational research and new enabling technologies, which are founded on
its success in developing and evaluating new optical technologies for
clinical research, diagnosis, and treatment. The section continues its work
in advancing technologies for isolating targeted cells for use in genomic and
proteomic investigation of tissue pathology and in studies of developing
organisms. Current emphasis is on developing an automated, laser-based
microtransfer method that employs cell-specific stains and that can be used
for proteomics and lipid-based studies. In addition, the section is
investigating the role of chronic phototoxicity in the outer retina as a
driving force for age-related macular degeneration (AMD), with the goal of
developing a biophysical model to predict photochemical changes in the eyes
of an aging population and of developing optical filters to arrest disease
progression. Amir Gandjbakhche’s
Section on Biomedical Stochastic Physics works primarily on
noninvasive optical imaging of biological tissues. The section is carrying
out a multifaceted experimental and computational research program that
incorporates mathematical and physical theories and technologies,
experimental models, and collaborative clinical investigations. Current
projects include time-resolved illumination of thick tissue for quantitative
spectroscopy of tumors, the use of specific fluorescent markers for
identifying disease processes, fluorescence-lifetime functional imaging,
near-infrared and visible light multispectral imaging, and multimodality
imaging combining thermography and laser-Doppler bloodflowmetry. The section
also has initiated a project to study aspects of tumor-induced angiogenesis
by using mathematical modeling and observations of tissue culture cells to
understand the proliferation and patterning of endothelial cells recruited
from existing blood vessels. Ralph Nossal’s group, the Section on Cell
Biophysics, aims to understand the physical basis for various cell
activities that involve structural changes in supramolecular biomolecular complexes.
The long-term goal is to build and use an arsenal of tools, both theoretical
and experimental, to study kinetic aspects of cell processes and to increase
knowledge of ways those activities can be mediated by external interventions.
The section’s activities include the use of fluorescence correlation
spectroscopy (FCS) to study the structure and stability of supramolecular
biological assemblies, the development of FCS and total internal reflectance
microscopy (TIRFM) to study events occurring on or near the plasma membranes
of live cells, and the creation of mathematical models to obtain estimates of
energies relating to the formation of
vesicles involved in intracellular trafficking. The section also carries out
a variety of projects on tubulin polymers, with emphasis on drug-tubulin
interactions and the ways that environmental factors affect formation of
tubulin polymers. |