Dual laser fluorescence correlation spectroscopy as a biophysical probe of binding interactions - Evaluation of new red-fluorescent dyes

In this work we characterized seven dyes that are one-photon excited and fluoresce in the far-red region of the visible spectrum, five of which became available only recently, as to their suitability as labels on the red emission channel in a two-color FCS method. Spectroscopic properties and binding to albumin were studied. In addition, when one of these was used as the label in a first-pass high-throughput screen with single-color fluorescence polarization detection, its foreseen advantage of avoiding the excitation of interfering background autofluorescence from compounds in libraries was deemed valuable after a comparison of two complete high-throughput screens of a chemical compound library at Abbott.