A Visible and Near-Infrared, Dual-Channel Fluorescence-On Probe for Selectively Tracking Mitochondrial Glutathione

Glutathione is a major endogenous antioxidant in biological systems. As a result, highly selective fluorescent probes are significant components of studies aimed at gaining a better understanding of the role(s) glutathione plays in biological functions. In this study, we developed a dual-channel turn-on fluorescent probe for glutathione, comprising naphthalimide and cyanine, bridged by a thiol-reactive sulfonamide moiety. The probe selectively responds to glutathione and is not affected by cysteine and homocysteine. Important information has been gained about the chemical mechanism for operation of the probe, which responds to glutathione in visible and near-infrared channels synchronously and independently. Moreover, this probe exhibits the remarkable capability of targeting mitochondria and dual-channel tracking of intracellular glutathione in a spatiotemporal and synchronous manner. We believe that the strategy used to design the new dual-channel fluorescence-on probe will be applicable to the design of fluorescent probes that display specific responses in multiple channels.