A Self-Quenching System Based on Bis-Naphthalimide: A Dual Two-Photon-Channel GSH Fluorescent Probe.

A single fluorescent signal output often does not satisfy the detection accuracy requirements for bioactive compounds in biological systems. It is of great interest to develop a dual-channel turn-on fluorescence sensing system for self-validated detection. Herein, we report a self-quenching nanoparticle composed of dual two-photon dyes of naphthalimides, displaying almost no fluorescence at both channels, owing to aggregation-caused quenching (ACQ). A dual two-photon-channel fluorescent probe for GSH was further developed by inserting a disulfide bond between two naphthalimides. Upon treatment with GSH, the disulfide bond was cleaved, and two napthalimide fluorophores were separated, leading to turn-on fluorescence at both channels. This dual-two-photon-channel design strategy can be easily extended to other analytes, simply by changing the linker molecules, which creates new opportunities to accurately monitor various biological processes in living cells.