A series of near-infrared fluorescent probes were designed based on the concept of emission control caused by interdye excitonic interaction. The fluorescent probes showed very weak emission in the unhybridized state, whereas they emitted near-infrared fluorescence after hybridization with the complementary nucleic acid. The hybridization-dependent switching of fluorescence emission made it possible to monitor mRNA in human cells in the range of near-infrared wavelengths.
A colorful bunch: A series of fluorescentprobes designed on the basis of fluorescence quenching caused by an excitonic interaction contain different dye moieties and fluoresce in various colors upon hybridization with their target nucleicacid. The picture shows simultaneous fluorescence in three colors in the nucleus of a cell containing an excess of three different microRNA strands. Left: differential