Autofluorescence Characteristics Of Mononuclear Cells And Human Leukemia Cells

Autofluorescence spectroscopy is a promising technique to explore and identify the endogenous fluorophores in normal and cancerous cells. The purpose of this study is to characterize the autofluorescence spectra of normal and leukemia cells. There are three fluorescence peaks occurred in the autofluorescence excitation-emission maxima (EEM), and the three peaks are 290-335 nm for tryptophan,340-445 nm for NAD(P)H,460-545 nm for FAD respectively.Autofluorescence spectra measurements of each cell line were performed over a wide range of cell concentrations in vitro. When the concentrations of cells less than 1 X 106 cells/mL, there is linear relationship between fluorescence intensity and concentration. When the concentrations of cells higher than 1×106 cells/mL, tryptophan fluorescence intensity is saturated with the increasing cell concentration. All of the leukemia cells indicated a statistically significant increase in the tryptophan fluorescence per cell relative to that of the normal cells, while no statistically significant differences were found in the NAD(P)H and FAD fluorescence per cell between the normal and any of the malignant cell lines. In addition, our results show that the measured fluorescence intensity of tryptophan is influenced by the size of cells. Finally, the fluorescence intensity ratio of tryptophan and NAD(P)H is used as data for linear discriminant analysis (LDA), which yielded 100% sensitivity and greater than 88.6% specificity. The result indicates that there is a good significant difference between normal cells and leukemia. These results show that autofluorescence spectroscopy has the potential to differentiate normal from leukemia cells.