Glutathione (GSH) as a biothiol is an essential peptide related to various diseases. Although multiple strategies for biothiols detection have been developed, there is increasing demand for sensors that can differentiate GSH from cysteine (Cys) and homocysteine (Hcy), owing to the similar structures and thiol groups in these amino acids. Herein, we report a novel Eu/LAPONITE (Lap)-based organic/inorganic hybrid material for selective detection of GSH via an "off-on" process. The fluorescence of Eu(DPA)@Lap-Tris can be quenched by Cu through photoinduced electron transfer (PET). The addition of GSH into the Eu(DPA)@Lap-Tris/Cu system induces the removal of Cu from Eu(DPA)@Lap-Tris and blocks PET, resulting in the recovery of fluorescence. This proposed assay demonstrates higher selectivity toward GSH than Cys and Hcy, and showed a detection limit of 162 nM within a linear range of 0.5-30 μM. Unlike other GSH selective sensors, this platform could be formed into a hydrogel while its sensitivity was maintained. The sensitive response to GSH in serum samples makes this platform an efficient tool for biological applications because of its ease of preparation, high selectivity, good biocompatibility, and low toxicity.

A novel magnetic/fluorometric bimodal sensor was built from carbon dots (CDs) and MnO2. The resulting sensor was sensitive to glutathione (GSH), leading to apparent enhancement of magnetic resonance (MR) and fluorescence signals along with visual changes. The bimodal detection strategy is based on the decomposition of the CDs-MnO2 through a redox reaction between GSH and MnO2. This process causes the transformation from non-MR-active MnO2 to MR-active Mn(2+), and is accompanied by fluorescence restoration of CDs. Compared with a range of other CDs, the polyethylenimine (PEI) passivated CDs (denoted as pCDs) were suitable for detection due to their positive surface potential. Cross-validation between MR and fluorescence provided detailed information regarding the MnO2 reduction process, and revealed the three distinct stages of the redox process. Thus, the design of a CD-based sensor for the magnetic/fluorometric bimodal detection of GSH was emphasized for the first time. This platform showed a detection limit of 0.6 μM with a linear range of 1-200 μM in the fluorescence mode, while the MR mode exhibited a linear range of 5-200 μM and a GSH detection limit of 2.8 μM with a visible change being observed rapidly at 1 μM in the MR images. Furthermore, the introduction of the MR mode allowed the biothiols to be easily identified. The integration of CD fluorescence with an MR response was demonstrated to be promising for providing detailed information and discriminating power, and therefore extend the application of CDs in sensing and imaging.

Calcium-activated chloride channels (CaCCs) play vital roles in a variety of physiological processes. Dysfunction of the CaCCs is implicated in many diseases. Drug discovery targeting at CaCCs has recently become possible with the determination that TMEM16A is the molecular identity of CaCCs. In this study, we demonstrated that resveratrol (RES), a Chinese traditional medicine compound, is a novel activator of TMEM16A. The yellow fluorescence protein quenching assay and measurement of intracellular calcium fluorescence intensity show that RES activates TMEM16A channels in an intracellular Ca-independent way. The data of inside-out patch clamp revealed that RES dose-dependently activates TMEM16A (EC = 47.92 ± 9.35 μM). Furthermore, RES enhanced the contractions of the ileum of guinea pigs by activating the TMEM16A channel, which indicated that RES might be a promising drug for the treatment of gastrointestinal hypomotility. As RES was able to induce TMEM16A channel activation, TMEM16A can be added to the list of RES drug targets.