Research Areas

Development of Novel Optical Biomarkers for Early Cancer Detection

Our project goal is to develop novel optical methods to non-invasively detect pre-cancerous lesions. Most cancers develop in the epithelium, a cell layer that covers or lines most organs. For example, cervical, oral, colon, breast and prostate cancers are all epithelial in origin. We focus on changes that are induced by human papilloma virus (HPV) infection, which is known to cause 95% of cervical cancers and approximately 25% of oral cancers. We are investigating the presence of light scattering and fluorescence signals that change when normal epithelial cells become transfected with HPV or when they undergo processes that are typically associated with the onset of cancer, such as apoptosis.

Collaborators:
Vadim Backman, Northwestern University, Department of Biomedical Engineering
Michael Feld, Massachusetts Institute of Technolgy, Department of Physics
Karl Munger, Harvard Medical School, Department of Pathology

Noninvasive biochemical and morphological assessment or apoptotic epithelial cells using autofluorescence microscopy

Fluorescence Biomarkers:
We are interested in developing non-invasive tools that are capable of detecting endogenous signals, naturally present in living cells. Since cells contain natural fluorophores including NAD(P)H and FAD (two co-enzymes responsible for metabolic energy transfer), and tryptophan (an amino acid) we can use fluorescence emission as a source of contrast. Using fluorescence microscopy, we are able to observe cell morphology and obtain biochemical information.

To quantify metabolic activity, we can calculate a redox ratio for a given sample. The redox ratio is defined at the FAD concentration to the total NADH and FAD concentration. Since NADH (reduced) and FAD (oxidized) are both used in cellular oxidative phosphorylation, the ratio of the two concentrations is inversely related to metabolic activity. By combining the metabolic activity information with spatial information, using image processing techniques, we are able to identify biomarkers of cellular processes as well as differentiate between normal and diseased tissue.

Light scattering:
The intrinsic light scattering properties of cells are investigated using Angular Light Scattering Spectroscopy (ALSS). This technique uses polarization gating to acquire maps of the angularly resolved, single backscattering of light from inhomogeneous samples, at wavelengths ranging from 450 to 730nm. As the angular distribution of backscattering is influenced by the intrinsic properties of the scattering medium such as size, size distribution and index of refraction contrast, this technique, together with an analytical model, is able to quantify the cell changes associated with neoplastic transformation.
 

Basic layout of the ALSS system

Light scattering map detected from polystyrene beads
(d=40μm; λ=650nm; cross polarized)

Abstracts and Conference Proceedings:

1. Georgakoudi I, Levitt J^g, Baldwin A, Papadakis A, Munger K. Intrinsic fluorescence changes associated with apoptosis of human epithelial keratinocytes. 4^th International Conference on Cervical Cancer, Houston, TX, May 2005. Gynecologic Oncology 2005; 99:854-857.
2. Levitt Jg, Baldwin A, Munger K, Georgakoudi I. Instrinsic Fluorescence Changes Associated With Cisplatin-induced Apoptosis of Human Epithelial Keratinocytes. Engineering Conferences International: Advances In Optics For Biotechnology, Medicine And Surgery, Copper Mountain, Colorado, July 24-28, 2005.
3. Levitt J^g, Xylas J^u, Baldwin A, Münger K, Georgakoudi I. Instrinsic fluorescence changes associated with cisplatin-induced apoptosis of human epithelial keratinocytes. 26th Annual meeting of the American Society of Lasers in Medicine and Surgery, Boston, MA, April 5-9, 2006.
4. Greiner C^g, Stucenski L^g, Boutrus S^g, Levitt J^g, Georgakoudi I. Tryptophan autofluorescence imaging of epithelial cells. 26^th Annual meeting of the American Society of Lasers in Medicine and Surgery, Boston, MA, April 5-9, 2006. Lasers Surg Med 2006; 86-86 289 Suppl. 18
5. Georgakoudi I, Levitt J^g, Mujat C, Greiner C^g, Stucenski L^g, Munger K. Development of Novel Biomarkers Based on Optical Tissue Spectroscopy and Imaging of Endogenous Signals. Presented at SPIE Photonics North meeting, Quebec City, Canada, June 2006.
6. J. Levitt^g, M. McLaughlin-Drubin, J. Garlick, K. Münger, I. Georgakoudi. Non-Invasive Assessment of Cell Differentiation in 3-D Tissue Models by Intrinsic Fluorescence Measurements. Gordon Research Conference: Lasers in Medicine and Biology, July 2-7, 2006.
7. Greiner C^g, L Stucenski^g, et al., Tryptophan, NADH and FAD autofluorescence imaging of normal, pre-cancerous and cancerous epithelial cells. Gordon Research Conference: Lasers in Medicine and Biology, July 2-7, 2006.
8. J. Xylas^u, J. Levitt^g, C. Egles, J. Garlick, I. Georgakoudi. Multi-photon imaging of endogenous chromophores in engineered normal and (pre-) cancerous tissues. Biomedical Engineering Society Annual Fall Meeting Friday, Oct 13 2006 Chicago, Illinois.
9. Greiner C^g, Mujat C, Baldwin A, Levitt J^g, Munger K and Georgakoudi I. Autofluorescence and light scattering signatures of normal and human papillomavirus immortalized human foreskin keratinocytes. Engineering Conferences International: Advances In Optics For Biotechnology, Medicine And Surgery, Naples FL, June 11-14, 2007.
10. Levitt J^g, McLaughlin-Drubin M, Xylas J^u, Garlick J, Munger K, Georgakoudi I. Quantitative characterization of biochemical and morphological changes of engineered normal, dysplastic and cancerous tissues. Engineering Conferences International: Advances In Optics For Biotechnology, Medicine And Surgery, Naples FL, June 11-14, 2007.

Papers

1. Georgakoudi I. The Color of Cancer. J. Luminescence 2006;119-120: 75-83.
2. Levitt J^g, Baldwin A, Papadakis A, Puri S^u, Xylas J^u, Munger K, Georgakoudi I. Intrinsic fluorescence and redox changes associated with apoptosis of primary epithelial cells. Journal of Biomedical Optics 2006;11:064012 (Cover feature).
3. Mujat C, Papadakis A, Tian F, Munger C, Georgakoudi I. Characterization of human epithelial keratinocytes with angular light scattering spectroscopy. Engineering Conferences International: Advances In Optics For Biotechnology, Medicine And Surgery, Copper Mountain, Colorado, July 24-28, 2005.
4. Mujat C, Papadakis A, Tian F, Munger K, Georgakoudi I. Light scattering spectroscopy investigation of human epithelial keratinocytes. 26^th Annual meeting of the American Society of Lasers in Medicine and Surgery, Boston, MA, April 5-9, 2006. Lasers Surg Med 2006: 16-16 45 Suppl.18.
5. Georgakoudi I, Levitt J^g, Baldwin A, Mujat C, Greiner C^g, Stucenski L^g, Munger K. Linear and non-linear optical microscopy and spectroscopy of human papilloma virus transfected cells. SPIE Optics East conference, Boston MA, September 2006.
6. Georgakoudi I, Van Dam J Characterization of Dysplastic Tissue Morphology and Biochemistry in Barrett’s Esophagus using Diffuse Reflectance