A novel strategy for rhodamine B-based fluorescent probes with a selective glutathione response for bioimaging in living cells.

The aim of this study was to overcome the reported shortcomings of the glutathione (GSH) detection of rhodamine-based fluorescent probes, such as poor selectivity to thiol groups and reversible unstable covalent binding with the thiol groups. Here, we have developed a simple and specific fluorescent probe based on rhodamine B, which can be used to selectively detect GSH in solution and perform bioimaging in living cells. This design strategy uses a specific reaction between allenamide and the GSH thiol group, which proceeds rapidly in a phosphate buffer/tetrahydrofuran (PBS/THF) mixture with specific selectivity, and forms a stable and irreversible conjugate. The combined simplicity and specificity of the recognition process enables it to serve as a fluorescent probe for detecting GSH level changes in living cells. Such a new recognizing strategy thus may open a new window for its further application in detecting GSH levels both in vitro and in vivo.