Highly sensitive benzothiazole-based chemosensors for detection and bioimaging of peroxynitrite in living cells.

It is well accepted that peroxynitrite (ONOO-) plays a crucial role in various physiological and pathological processes. Thus, the detection and imaging of ONOO- in vitro and in vivo with high selectivity and sensitivity is of great significance. Here we report two simple benzothiazole-based fluorescent chemosensors, BS1 and BS2. Under physiological pH, both probes could quickly sense ONOO- with a remarkable "turn-on" fluorescence signal at 430 nm. The limit of detection (LOD) of BS1 and BS2 toward ONOO- was 12.8 nM and 25.2 nM, respectively, much lower than the reported values. Experimental results indicated that BS1 with a diphenyl phosphonate unit presented higher selectivity for ONOO- than BS2. Furthermore, based on the advantages of lower cytotoxicity and pH-stabilities of BS1, probe BS1 was successfully employed to detect and image ONOO- in HepG2 cells. More importantly, we used BS1 to successfully showcase drug-induced hepatotoxicity via imaging ONOO- upregulated by acetaminophen (APAP), and also evaluated the remediation effect of GSH. All the results illustrated that the fluorescent probe BS1 has great potential for the detection of ONOO- and to further uncover the roles of ONOO- during the drug-induced liver injury (DILI) process.

Shape controllable MoS2 nanocrystals prepared by the single precursor route for electrocatalytic hydrogen evolution.

MoS2 has attracted great attention as a prospective electrocatalyst for generating hydrogen via water electrolysis due to its abundant and inexpensive sources. However, bulk MoS2 has weak electrocatalytic activity because of its low electrical conductivity and few edge-active sites. Controllable synthesis of MoS2 with ultrasmall size or complex morphology may be an available strategy to boost its conductivity and edge-active sites. Herein, a facile single-precursor strategy was developed to prepare nanoscale MoS2 with various morphologies, including quantum dots, nanorods, nanoribbons, and nanosheets. In-depth studies show that the formation of MoS2 with various shapes is determined by both kinetic and thermodynamic factors such as reaction time and temperature. Electrocatalytic tests reveal that MoS2 quantum dots have high electrocatalytic performance with a low overpotential of 255 mV and a small Tafel slope of 66 mV dec-1 due to the abundant exposed active edges and excellent intrinsic conductivity.

Rhodamine-based chemosensor for Sn2+ detection and its application in nanofibrous film and bioimaging.

A simple rhodamine-based compound CK was designed and synthesized as a fluorescent chemosensor for Sn2+ based on Sn2+-mediated cyclization. The optical investigation indicated that the probe could quantitatively detect Sn2+ in a concentration range of 10-30 µM, with a detection limit of 118 nM. Moreover, probe CK, with low cytotoxicity, was successfully applied for imaging of Sn2+ in HeLa cells and mice, exhibiting excellent biocompatibility and cell membrane permeability. For on-site monitoring, CK-hybridized polymethyl methacrylate (PMMA) nanofibers were prepared by electrospinning and successfully employed for the visual detection of Sn2+ in actual samples. All the results demonstrated that the chemosensor could be a promising tool for the detection of Sn2+ in vitro and in vivo.

Polyvinylpyrrolidone-assisted synthesis of highly water-stable cadmium-based metal-organic framework nanosheets for the detection of metronidazole.

Recently, much effort has been dedicated to ultra-thin two-dimensional metal-organic framework (2D MOF) nanosheets due to their outstanding properties, such as ultra-thin morphology, large specific surface area, abundant modifiable active sites, etc. However, the preparation of high-quality 2D MOF nanosheets in good yields still remains a huge challenge. Herein, we report 2D cadmium-based metal-organic framework (Cd-MOF) nanosheets prepared in a one-pot polyvinylpyrrolidone (PVP)-assisted synthesis method with high yield. The Cd-MOF nanosheets were characterized with good stability and dispersion in aqueous systems, and were highly selective and sensitive to the antibiotic metronidazole (MNZ) with low limit of detection (LOD: 0.10 µM), thus providing a new and promising fluorescent sensor for rapid detection of MNZ in aqueous solution.