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Updated: May 15, 2026

Synthesis of Wavelength-shifting DNA Hybridization Probes by Using Photostable Cyanine Dyes
Published on: July 6, 2016
Phosphine quenching of cyanine dyes as a versatile tool for fluorescence microscopy
Joshua C Vaughan1, Graham T Dempsey, Eileen Sun
1Howard Hughes Medical Institute, and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Abstract:
We report that the cyanine dye Cy5 and several of its structural relatives are reversibly quenched by the phosphine tris(2-carboxyethyl)phosphine (TCEP). Using Cy5 as a model, we show that the quenching reaction occurs by 1,4-addition of the phosphine to the polymethine bridge of Cy5 to form a covalent adduct. Illumination with UV light dissociates the adduct and returns the dye to the fluorescent state. We demonstrate that TCEP quenching can be used for super-resolution imaging as well as for other applications, such as differentiating between molecules inside and outside the cell.
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