A method for determining supernatant-free spectra generated from fluorescently stained cells in suspension

•We present a cuvette holder for the front-face fluorometry of pelleted cell layers.•Supernatant-free fluorescence spectra of cells in suspension were measured.•Yeast cells stained with calcofluor and 3,3′-dipropylthiadicarbocyanine were used.•The presented method is also suitable for any other cell type and fluorescent dye.

Here we present a fluorometric method for direct determination of supernatant-free fluorescence spectra generated from fluorescently stained cells in suspension. The key element in the new technique is the design of an adapter to a standard cuvette holder that makes it possible to measure front-face fluorescence spectra from thin layers of cells spun down to the bottom of a spectrofluorometric cuvette. We have demonstrated the applicability of this approach and its analytical potential using the suspensions of yeast cells stained with the potentiometric dye of 3,3’-dipropylthiadicarbocyanine, diS-C3(3), and with the specific cell-wall marker calcofluor.

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