The National Institute of Diabetes & Digestive & Kidney Diseases

Our research interests lie primarily in the applications of vibrational infrared and Raman spectroscopic techniques toward the elucidation of the conformational, dynamical, thermodynamic, and functional properties of both intact and model membrane assemblies and related systems. Emphasis is placed on investigating the specific lipid-lipid and lipid-protein interactions governing biomembrane reorganizations. In particular, our efforts are directed toward defining and characterizing lipid microdomain formation as it pertains both to the existence of lateral heterogeneities and transverse asymmetries within biological membranes and to the ability and extent of these fluctuating microclusters, or domain motifs, to modulate integral membrane protein behavior. We also probe heterogeneity at the tissue level using newly developed infrared and Raman and visual reflectance spectroscopic imaging microscopy approaches. For example, using tissue microarrays we investigate tissue sample segmentation with state-of-the-art instrumentation capable of rapidly generating high fidelity infrared spectroscopic images reflecting conditions of moderate partial resolution and high spectral resolution. This novel instrumentation integrates infrared sensitive two-dimensional focal-plane array detectors with either step-scanning or continuous scanning interferometer coupled to infrared microscopes. New instrumentation, experimental approaches and chemometric methodologies for treating the image and spectroscopic data are under continuing development and modification.

Chen, T., Lee, M., Kim, Y., Lee, S., Kummar, S., Guiterrez, M., Hewitt, S., Trepel, J., and Levin, I.W.: Pharmacodynamic Assessment of Histone Deacetylase Inhibitors: Infrared Vibrational Spectroscopic Imaging of Protein Acetylation. Analytical Chemistry. In Press.

Crane, N. J., McHone, B., Hawksworth, J., Denobile, J., Pearl, J., Tadaki, D.,Pinto, P.A., Levin. I. W., and Elster, E. A.: Enhanced surgical Imaging: Laparoscopic Vessel Identification and Assessment of Tissue Oxygenation. Journal of the American College of Surgeons. In Press.

Bhargava, R. and Levin, I.W.: Infrared Spectroscopic Imaging Protocols for High Throughput Histopathology. Chapter in “Vibrational Spectroscopy for Medical Diagnoses”, M. Diem and P. Griffiths, Eds. John Wiley and Sons, Ltd., 2008.

Schultz, Z.D. and Levin, I.W.: Lipid Microdomain Formation: Characterization of a ternary Galactocerebroside/Dipalmitoylphosphatidlycholine/Cholesterol Membrane Bilayer by Infrared Spectroscopy and Ultrasonic Velocimetry. Biophysical Journal, 94, 3104-3114 (2008).

Crane, N. J., Schultz, Z. D., and Levin, I.W.: Contrast enhancement for in vivo visible reflectance imaging of tissue oxygenation. Applied Spectroscopy, 61, 797-803, 2007.

Bhargava, R., Fernandez D. C., Hewitt, S. M., and Levin, I.W.: High throughput assessment of cells and tissues: Bayesian classification of spectral metrics from infrared vibrational spectroscopic imaging data. Biochimica Biophysica Acta: Biomembranes. 1758, 830-845 (2006).

Schlucker, S., Liang, C., Strehle, K. R., DiGiovanna, J.J.., Kraemer, K. H. and Levin, I.W.: Conformational Differences in Protein Disulfide Linkages Between Normal Hair and Hair from Subjects with Trichothiodystrophy: A Quantitative Analysis by Raman Spectroscopy. Biopolymers, 82, 615-622 (2006).

Levin, I. W. and Bhargava, R.: Fourier Transform Infrared Spectroscopic Imaging: Integrating Microscopy and Molecular Recognition. Annual Reviews of Physical Chemistry, 2005. 56: 429-474.

Fernandez, D. C., Bhargava, R., Hewitt, S. M. and Levin, I. W.: Infrared Spectroscopic Imaging for Histopathologic Recognition. Nature Biotechnology, 23, 469-474, 2005.

Bhargava, R. and Levin, I. W. : Enhanced Time-resolved Fourier Transform Infrared Spectroscopic Imaging for Reversible Dynamics. Journal of Physical Chemistry (A), 108, 3896-3901, 2004.

Bhargava, R. and Levin, I. W. Enhanced Time-resolved Fourier Transform Infrared Spectroscopic Imaging for Reversible Dynamics Journal of Physical Chemistry (A)(108): 3896-3901, 2004.

Bhargava R, Levin IW Gram-Schmidt orthogonalization for rapid reconstructions of Fourier transform infrared spectroscopic imaging data. Appl Spectrosc (58): 995-1000, 2004. [Full Text/Abstract]

Huffman SW, Schlucker S, Levin IW Reorganizational dynamics of multilamellar lipid bilayer assemblies using continuously scanning Fourier transform infrared spectroscopic imaging. Chem Phys Lipids (130): 167-74, 2004. [Full Text/Abstract]

Schlucker, S., Huffman, S. W. and Levin, I. W. Vibrational Microspectroscopic Imaging: Spatial Resolution Enhancement Biomedical Vibrational Spectroscopy, SPIE, International Society for Optical Engineering(5): 157-163, 2004.

Schlucker S, Schaeberle MD, Huffman SW, Levin IW Raman microspectroscopy: a comparison of point, line, and wide-field imaging methodologies. Anal Chem (75): 4312-8, 2003. [Full Text/Abstract]