Substitution of oxygen with silicon: A big step forward for fluorescent dyes in life science

In 2008, a concept of element substitution was proposed for designing long wavelength fluorescent dyes which is urgently desired in life science. By replacing the rhodamine dyes’ oxygen-bridge atom by silicon we gained a nearly 90 nm's red shift. At the same time, the novel silicon-substituted dye kept a high brightness similar to conventional rhodamines. Since our report was published, the values of this pioneering work have been evidently displayed. This idea is so practical that a large number of Silicon-rhodamine derivatives have been developed as fluorescent sensors and probes by a lot of research teams. And this strategic innovation is also very illuminating to initiate the generations of quite a few wonderful element-substituted dyes, among which the elements are no longer limited in silicon, and the dye precursors are not limited in rhodamines either. In this minireview, we would like to present this original concept as a tutorial guidance, then to briefly comment the major practices of this strategy, and finally to prospect the future trend of the element substituted fluorescent dyes.