Phosphine Quenching of Cyanine Dyes as a Versatile Tool for Fluorescence Microscopy

ArticleinJournal of the American Chemical Society 135(4) · January 2013with24 Reads
Impact Factor: 12.11 · DOI: 10.1021/ja3105279 · Source: PubMed


    We report that the cyanine dye Cy5 and several of its structural relatives are reversibly quenched by the phosphine TCEP (tris(2-carboxyethyl)phosphine). 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 ultraviolet light dissociates the adduct and returns the dye to the fluorescent state. We demonstrate that TCEP quenching can be used for superresolution imaging as well as for other applications, such as differentiating between molecules inside and outside the cell.