Recently, the development of new fluorescent probes for the ratiometric detection of target objects inside living cells has received great attention. Normally, the preparation, modification as well as conjugation procedures of these probes are complicated. On this basis, great efforts have been paid to establish convenient method for the preparation of dual emissive nanosensor. In this work, a functional dual emissive carbon dots (dCDs) was prepared by a one-pot hydrothermal carbonization method. The dCDs exhibits two distinctive fluorescence emission peaks at 440 and 624 nm with the excitation at 380 nm. Different from the commonly reported dCDs, this probe exhibited an interesting wavelength dependent dual responsive functionality toward lysine (440 nm) and pH (624 nm), enabling the ratiometric detection of these two targets. The quantitative analysis displayed that a linear range of 0.5-260 μM with a detection limit of 94 nM toward lysine and the differentiation of pH variation from 1.5 to 5.0 could be readily realized in a ratiometric strategy, which was not reported before with other carbon dots (CDs) as the probe. Furthermore, because of the low cytotoxicity, good optical and colloidal stability, and excellent wavelength dependent sensitivity and selectivity toward lysine and pH, this probe was successfully applied to monitor the dynamic variation of lysine and pH in cellular systems, demonstrating the promising applicability for biosensing in the future.

Ratiometric Detection of Intracellular Lysine and pH with One-Pot Synthesized Dual Emissive Carbon Dots

Glutathione plays many important roles in biological processes; however, the dynamic changes of glutathione concentrations in living cells remain largely unknown. Here, we report a reversible reaction-based fluorescent probe-designated as RealThiol (RT)-that can quantitatively monitor the real-time glutathione dynamics in living cells. Using RT, we observe enhanced antioxidant capability of activated neurons and dynamic glutathione changes during ferroptosis. RT is thus a versatile tool that can be used for both confocal microscopy and flow cytometry based high-throughput quantification of glutathione levels in single cells. We envision that this new glutathione probe will enable opportunities to study glutathione dynamics and transportation and expand our understanding of the physiological and pathological roles of glutathione in living cells.

/pdf/quantitative-real-time-imaging-of-glutathione-1alc8kemfx.pdf

Quantitative real-time imaging of glutathione

Recent progress on the development of glutathione (GSH) selective fluorescent and colorimetric probes

Glutathione (GSH) mediates a wide variety of biological events and human diseases. Although it has been the subject of intense study in recent years, a further understanding of its molecular mechanisms and metabolism routes in living cells has remained limited due to a lack of appropriate analytical tools. Sulfur dioxide (SO2), an important metabolite of GSH, is usually associated with the symptoms of neurological disorders, cardiovascular diseases, and lung cancer. Herein, a novel multisignal fluorescent probe was rationally designed and exploited for the simultaneous detection of GSH and its metabolite SO2 via an ICT-FRET synergetic mechanism. The probe shows completely reversed fluorescence responses toward GSH (enhanced red emission) and SO2 (annihilated red fluorescence) with high selectivity and sensitivity. In particular, the probe displayed completely different fluorescent signals (blue-shift) with SO2 in the presence of GSH, thereby allowing the imaging of the metabolism process of GSH to SO2 in two independent channels without spectral cross interference. Given these advantages, this probe has been successfully applied to the real-time monitoring of the SO2 metabolic process in living cells and mice models, and it has thus been found that GSH can metabolize SO2 by enzymatic reaction with TST (thiosulfate sulphurtransferase); additionally, SO2 was transformed into sulfate under SUOX (sulfite oxidase). We anticipate that this research will provide a convenient and efficient tool for understanding the interrelated physiological functions of GSH and SO2 in more biosystems.

Employing an ICT-FRET Integration Platform for the Real-Time Tracking of SO2 Metabolism in Cancer Cells and Tumor Models

Studying numerous biologically important species simultaneously is crucial to understanding cellular functions and the root causes of related diseases. Direct visualization of endogenous biothiols in biological systems is of great value to understanding their biological roles. Herein, a novel multi-signal fluorescent probe was rationally designed and exploited for the simultaneous sensing of homocysteine (Hcy), cysteine (Cys), and glutathione (GSH) using different emission channels. This probe was successfully applied to the simultaneous discrimination between and visualization of endogenous Hcy, Cys, GSH, and their transformation in living cells.

Simultaneous Visualization of Endogenous Homocysteine, Cysteine, Glutathione, and their Transformation through Different Fluorescence Channels

The ability to monitor and quantify glutathione (GSH) in live cells is essential in order to gain a detailed understanding of GSH-related pathological events. However, owing to their irreversible response mechanisms, most existing fluorescent GSH probes are not suitable for this purpose. We have developed a ratiometric fluorescent probe (QG-1) for quantitatively monitoring cellular GSH. The probe responds specifically and reversibility to GSH with an ideal dissociation constant (Kd) of 2.59 mm and a fast response time (t1/2=5.82 s). We also demonstrate that QG-1 detection of GSH is feasible in a model protein system. QG-1 was found to have extremely low cytotoxicity and was applied to determine the GSH concentration in live HeLa cells (5.40±0.87 mm).

A Reversible Fluorescent Probe for Real-Time Quantitative Monitoring of Cellular Glutathione.

A mitochondria-targeted fluorescent probe for fast detecting hypochlorite in living cells

A reversible fluorescent chemosensor for selective and sequential detection of copper ion and sulfide

https://onlinelibrary.wiley.com/doi/pdf/10.1002/anie.201903621

Corrigendum: A Reversible Fluorescent Probe for Real-Time Quantitative Monitoring of Cellular Glutathione

The invention discloses application of a benzoquinone derivative (2,5-dimethyl p-benzoquinone or tertiary butyl p-benzoquinone) to preparation of medicine for resisting hepatofibrosis, and belongs to the technical field of medicine. Study proves that the 2,5-dimethyl p-benzoquinone or tertiary butyl p-benzoquinone can reduce the LPS receptor proteins CD14 and LR4 and reduce the expression of p-PI3K and p-AKt proteins to inhibit the HSC (hepatic stellate cell) activation due to LPS by regulating the TLR4 signal paths; meanwhile, the activated HSC can be promoted to generate apoptosis by lowering Pro-caspase3, Bcl-2/Bax, XIAP and FILP protein expression; finally, through reducing the expression of alpha-SMA and Collagen I, certain hepatofibrosis resisting activity can be expressed. Therefore the compound has certain novel application when being used for preparing the medicine for resisting hepatofibrosis.

Yu Miao

Papers

A Reversible Fluorescent Probe for Real-Time Quantitative Monitoring of Cellular Glutathione.

A mitochondria-targeted fluorescent probe for fast detecting hypochlorite in living cells

A reversible fluorescent chemosensor for selective and sequential detection of copper ion and sulfide

Corrigendum: A Reversible Fluorescent Probe for Real-Time Quantitative Monitoring of Cellular Glutathione

Application of benzoquinone derivative to preparation of medicine for resisting hepatofibrosis