Construction of a unique fluorescent probe for rapid and highly sensitive detection of glutathione in living cells and zebrafish.

A rhodamine-based fluorescent probe (Rho-GSH) was rationally designed and synthesized, using nitrobenzene as recognition group for monitoring and imaging GSH in vitro and in vivo. In the presence of GSH, Rho-GSH undergoes sequential nucleophilic substitution and spiro-ring-opening reaction, resulting the fluorescence increase of probe, which enables quantitative detection of GSH with "off-on" fluorescence. The cascade reaction also enables Rho-GSH to rapidly detect GSH (3 s). In addition, Rho-GSH exhibited outstanding selectivity in detecting GSH vs cysteine (Cys) and homocysteine (Hcy). Based on the outstanding detection performance and superior biocompatibility of Rho-GSH , it was used to visualize GSH in vitro and in vivo , demonstrating its highly selectivity for GSH detection (with respect to Cys and Hcy). Rho-GSH can help visually distinguishing cancer cells from normal cells by fluorescence imaging, demonstrating the overexpression of GSH in cancer cells. Because of the outstanding analytical capabilities of Rho-GSH for GSH detection, Rho-GSH may be useful for cancer diagnosis and clinical evaluation. [Display omitted] • Rho-GSH is a rhodamine-based fluorescent probe based on cascade reactions. • Rho-GSH can quantitatively detect GSH with high selectivity and rapidity (3 s). • Rho-GSH can visualize GSH in vitro and in vivo. • Rho-GSH distinguishes cancer cells from normal cells. [ABSTRACT FROM AUTHOR]