Our research, which has been supported for the past twenty years by the
National Institutes of Health, centers around applications of infrared
spectroscopy to biophysical and biomedical problems. Three projects currently
underway offer a good illustration of the nature of this work.
(1) We have designed and built a unique spectrometer interfaced with a
surface balance to acquire IR spectra from monomolecular films of
phospholipids and proteins at the air/water interface. The device has been
used to test the "squeeze-out" hypothesis of lung surfactant function, a
central issue in pulmonary physiology. Future work will involve precise
determination of biomolecular conformation and orientation at the air/water
(2) We have developed IR experiments to quantitatively describe the nature
and location of conformational disorder in phospholipid acyl chains. This
approach has been used to determine the physical state of the membranes in
living cells of a microorganism. Future work will examine the molecular basis
of homeoviscous adaptation (how biological membranes respond to environmental alterations), as well as development of additional spectra-structure correlations.
(3) We have undertaken the first IR Microscopy studies of bio-mineralizing
tissues. Methods have been developed to determine the size and perfection
of the hydroxyapatite crystals in diffraction limited (10 micron) samples,
the orientation of carbonate ions which substitute for the phosphate in the
hydroxyapatite lattice, and the relative amounts of mineral and protein in
various tissue sites. Each of these quantities is altered during pathological
states such as osteoporosis or vitamin D deficiency. Future work will attempt
to develop biodiagnostic assays for the efficacy of therapeutic interventions.
Ph.D. 1972, M.I.T.
Postdoctoral fellowship, MRC Biophysics Unit, King's College, London
Research Research Associate, Division of Chemistry, National Research Council of Canada, Ottawa