Detection of Near Infrared Fluorescent Molecules by Flow Cytometry Enables Novel Applications in Vision Research

Authors

• RS Villasmil
• JA Minehart
• W Ma
• A George
• R Sharma
• J Tam

Abstract

Flow cytometers excel at detecting ultraviolet and visible electromagnetic radiation. Photomultiplier tube detectors in conventional cytometers often underperform in the near-infrared (NIR) spectrum. We have detected two NIR fluorescent molecules, indocyanine green and melanin, with the novel avalanche photodiode detectors used in state-of-the-art flow cytometers. Indocyanine green dye is used in Indocyanine Green Chorioangiography (IGC), a medical diagnostic procedure that captures images of the eye's interior blood vessels. Melanin, a natural retinal pigment, allows the eye to tolerate most kinds of bright light without damage. Fluorescence in cells labeled with either of these two NIR fluorescent molecules was detected using 808 nm of excitation and avalanche photodiode detectors behind 840/20 and 885/40 filters. Detection of NIR fluorescence above 808 nm by flow cytometry enables quantitative analysis of single cells involved in IGC and melanin expression. This detection capability is useful in the clinical research in albinism and novel intraocular imaging.

Scientific Focus Area: Biomedical Engineering and Biophysics

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