Double labeling and comparison of fluorescence intensity and photostability between quantum dots and FITC in oral tumors.

The aim of this study was to evaluate the application of quantum dots (QDs) and the FITC labeling technique in Tca8113 cells, and to compare the fluorescence intensity and photostability of these techniques. First, using one-colour confocal microscopy, QDs and FITC were applied separately to tag HSP70 in Tca8113 strains with indirect immunofluorescence. The expression of HSP70 in Tca8113 cells was observed using confocal laser microscopy, and the fluorescence intensity between QDs and FITC was compared. Using two-colour confocal microscopy, QDs and FITC were applied to tag survivin and HSP70, respectively, in order to compare the fluorescence photostability between QDs and FITC. Using a laser scanning microscope, survivin and HSP70 expression was clearly detected in the Tca8113 cells. The strength of the fluorescence signal from QDs was higher than that from FITC. After 40 min of continuous laser exposure, there was no observable decline in the QD fluorescent markers, whereas the FITC fluorescent signals faded very quickly and became undetectable. QDs have better fluorescence intensity and photostability than FITC, and are more appropriate for studies that require a long dynamic observation of physiological changes in cells.