A novel near-infrared fluorescent sensor for zero background nitrite detection via the "covalent-assembly" principle.

Different chemical states of nitrogen are present in many freshwater and marine ecosystems, and nitrite ions are one of the most toxic water-soluble nitrogen species. Developing an effective and convenient sensing method to constantly detect the concentration of nitrite has become a wide concern. Here, a novel near-infrared fluorescent probe (AAC) was designed and synthesized via the "covalent assembly" principle, showing excellent selectivity and high sensitivity for nitrite. A new nitrite-quantitative method was established with the help of AAC, and the detection limit of nitrite using the new method was as low as 6.7 nM. AAC was successfully applied for the quantitative detection of nitrite in real-world environmental and food samples (including river water and Chinese sauerkraut), and the detection results were essentially identical to the results obtained from the traditional Griess assay. Moreover, AAC was successfully applied for tracking nitrite in Escherichia coli by fluorescence imaging. Since nitrite can have devastating effects, the method established with AAC allowed us to "see" effectively about the water quality, food quality, etc.

A reaction-based ratiometric fluorescent sensor for the detection of Hg(ii) ions in both cells and bacteria.

A novel reaction-based fluorescent probe (ATC-Hg) was designed and synthesized via the "covalent assembly" principle, which exhibited excellent selectivity and high sensitivity for Hg2+ and CH3Hg+. Moreover, it is the first Hg(ii) sensitive fluorescent probe that has been successfully applied in imaging in both cells and Escherichia coli.

BODIPY-Based Two-Photon Fluorescent Probe for Real-Time Monitoring of Lysosomal Viscosity with Fluorescence Lifetime Imaging Microscopy.

The viscosity of lysosome is reported to be a key indicator of lysosomal functionality. However, the existing mechanical methods of viscosity measurement can hardly be applied at the cellular or subcellular level. Herein, a BODIPY-based two-photon fluorescent probe was presented for monitoring lysosomal viscosity with high spatial and temporal resolution. By installing two morpholine moieties to the fluorophore as target and rotational groups, the TICT effect between the two morpholine rings and the main fluorophore scaffold endowed the probe with excellent viscosity sensitivity. Moreover, Lyso-B succeeded in showing the impact of dexamethasone on lysosomal viscosity in real time.

BINOL derivatives with aggression-induced emission.

As fluorescent probes, the small Stokes shift and ACQ effect limit the application of BINOL derivatives. Herein, a new series of BINOL derivatives were synthesized which could be turned from ACQ to AIE fluorophores by changing the electron withdrawing group. Among these compounds, BIN-COP exhibits an obvious AIE property with low cytotoxicity. The bioimaging performance indicated that the designed fluorophores could be successfully used for bioimaging.

Tetraphenylethene-pyridine salts as the first self-assembling chemosensor for pyrophosphate.

We presented a novel approach for pyrophosphate (PPi) sensing. Two tetraphenylethene (TPE)-functionalised pyridine salts (TPM and TPH) were designed and synthesized. Both of them exhibited weak emission in the solution state that originates from intramolecular charge transfer (ICT) from TPE to the pyridine; the addition of PPi into the TPM aqueous solution would enhance the fluorescence intensity, which eliminates the emission quenching effect of the iodide ion by the formation of PPi-sensor nanoparticles. The detection limit of TPM was determined to be as low as 133 nM. Meanwhile, a thin solid film of TPM that could detect PPi rapidly was conveniently prepared.