UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-22 2:38
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Conference: Bucharest University Faculty of Physics 2004 Meeting


Section: Electricity and Biophysics


Title:
Autofluorescence spectroscopy of cell suspensions


Authors:
Serghei Ludmila *, Sandrine Villette **, Geneviève Bourg-Heckly**


Affiliation:
* University of Bucharest, Faculty of Physics, ** Laboratoire de Physicochimie Biomoléculaire et Cellulaire (LPBC), Université Pierre et Marie Curie, Paris


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Keywords:
fluorescence spectroscopy, esophagus mucosa, neoplasm


Abstract:
The analysis of the contribution of the intracellular fluorescence to the global esophageal tissular autofluorescence allows a better understanding of the origins of the spectral modifications observed during the neoplasmic transformation of the esophagus mucosa. As esophageal cancer is mostly either squamous cell carcinoma arising from normal esophageal epithelium (80% of cases) or adenocarcinoma in Barrett’s esophagus, Autofluorescence of normal cells was compared with these cells lines (OE21 and OE33, respectively), bought from ECACC (European Collection of Cell Culture). Autofluorescence spectra of healthy and tumoral cells from esophageal mucosa show significant differences that can be used for diagnostic purposes. For an excitation wavelength in the near UV, the intensity and spectral distribution of autofluorescence are related to the tissue structure (through collagen and elastin emissions), the cellular metabolism (through NAD(P)H and flavins emissions) and are strongly affected by the optical properties of tissue (absorption and diffusion). The samples were measured in the right angle geometry in a quartz cuvette of 10 mm path length using a Varian Cary Eclipse fluorescence spectrophotometer. The emission fluorescence spectra were recorded between 400 nm and 560 nm, with excitation set at 351 nm. For the three cell types all spectra exhibit an emission band extending to 600 nm with a peak around 443 nm. Under near UV excitation the major fluorophore is NAD(P)H coenzyme. Under this excitation the flavins excitation coefficient is very low. The mean autofluorescence intensity is significantly higher in tumoral cells than in normal ones. A possible explanation for the larger amount of the NAD(P)H reduced form in tumoral cells is that aerobic energy metabolism is less important in neoplastic cells than in normal ones, which results in an increase in the reduced fraction of pyridine nucleotides.