Quantitative Evaluation of Dielectrophoretic Captured Fluorescent-Labeled Exosomes

Exosomes derived from cells have great potential as a biomarker for early-stage cancer diagnosis. Recently, we demonstrated the separation of exosomes derived from cancer and normal cells, respectively, utilizing dielectrophoresis (DEP). In the separation, the exosomes were labeled with fluorescent dyes to observe by an optical microscope. In this report, an evaluation method of the exosome concentration based on the fluorescence intensity was proposed. The evaluation method includes the effect of the photobleaching of fluorescent dye to improve the accuracy. The photobleaching property was experimentally investigated in order to obtain a calibration equation. The proposed method was applied to the quantitative evaluation of DEP-captured exosomes.