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Ginsenoside Compound K (GCK) is the main metabolite of natural protopanaxadiol ginsenosides with diverse pharmacological effects. Gut microbiota contributes to the biotransformation of GCK, while the effect of gut microbiota on the pharmacokinetics of GCK in vivo remains unclear. To illustrate the role of gut microbiota in GCK metabolism in vivo, a systematic investigation of the pharmacokinetics of GCK in specific pathogen free (SPF) and pseudo-germ-free (pseudo-GF) rats were conducted. Pseudo-GF rats were treated with non-absorbable antibiotics. Liquid chromatography tandem mass spectrometry (LC–MS/MS) was validated for the quantification of GCK in rat plasma. Compared with SPF rats, the plasma concentration of GCK significantly increased after the gut microbiota depleted. The results showed that GCK absorption slowed down, Tmax delayed by 3.5 h, AUC0-11 increased by 1.3 times, CLz/F decreased by 0.6 times in pseudo-GF rats, and Cmax was 1.6 times higher than that of normal rats. The data indicated that gut microbiota played an important role in the pharmacokinetics of GCK in vivo. [ABSTRACT FROM AUTHOR]

Exocytosis involving the fusion of intracellular vesicles with cell membrane, is thought to be modulated by the mechanical cues in the microenvironment. Single‐cell electrochemistry can offer unique information about the quantification and kinetics of exocytotic events; however, the effects of mechanical force on vesicular release have been poorly explored. Herein, we developed a stretchable microelectrode with excellent electrochemical stability under mechanical deformation by microfabrication of functionalized poly(3,4‐ethylenedioxythiophene) conductive ink, which achieved real‐time quantitation of strain‐induced vesicular exocytosis from a single cell for the first time. We found that mechanical strain could cause calcium influx via the activation of Piezo1 channels in chromaffin cell, initiating the vesicular exocytosis process. Interestingly, mechanical strain increases the amount of catecholamines released by accelerating the opening and prolonging the closing of fusion pore during exocytosis. This work is expected to provide revealing insights into the regulatory effects of mechanical stimuli on vesicular exocytosis. [ABSTRACT FROM AUTHOR]

ATP plays a crucial role in cell energy supply, so the quantification of intracellular ATP levels is particularly important for understanding many physio-pathological processes. The intracellular quantification of this non-electroactive molecule can be realized using aptamer-modified nanoelectrodes, but is hindered by the limited quantity of modification and electroactive tags on the nanosized electrodes. Herein, we developed a simple but effective electrochemical signal amplification strategy for intracellular ATP detection, which replaces the regular ATP aptamer-linked ferrocene monomer with a polymer, thus greatly magnifying the amounts of electrochemical reporters linked to one chain of the aptamer and enhancing the signals. This ferrocene polymer–ATP aptamer was further immobilized onto Au nanowire electrodes (SiC@C@Au NWEs) to achieve accurate quantification of intracellular ATP in single cells, presenting high electrochemical signal output and high specificity. This work not only provides a powerful tool for quantifying intracellular ATP but also offers a simple and versatile strategy for electrochemical signal amplification in the detection of broader non-electroactive molecules involved in different kinds of intracellular physiological processes. [ABSTRACT FROM AUTHOR]

Airborne nanoplastics can enter alveolar cells and trigger intracellular oxidative stress primarily. Herein, taking advantage of the high electrochemical resolution of SiC@Pt nanoelectrodes, we achieved the quantitative discrimination of the major ROS/RNS within A549 cells, disclosed the sources of their precursors, and observed that the NO (RNS precursor) level significantly increased, whereas O2˙− (ROS precursor) remained relatively stable during the nanoplastics exposure. This establishes that iNOS or mitochondrion-targeted treatment may be a preventive or therapeutic strategy for nanoplastic-induced lung injury. [ABSTRACT FROM AUTHOR]

The glutathione (GSH) system is one of the most powerful intracellular antioxidant systems for the elimination of reactive oxygen species (ROS) and maintaining cellular redox homeostasis. However, the rapid kinetics information (at the millisecond to the second level) during the dynamic antioxidation process of the GSH system remains unclear. As such, we specifically developed a novel dual‐wire nanosensor (DWNS) that can selectively and synchronously measure the levels of GSH and ROS with high temporal resolution, and applied it to monitor the transient ROS generation as well as the rapid antioxidation process of the GSH system in individual cancer cells. These measurements revealed that the glutathione peroxidase (GPx) in the GSH system is rapidly initiated against ROS burst in a sub‐second time scale, but the elimination process is short‐lived, ending after a few seconds, while some ROS are still present in the cells. This study is expected to open new perspectives for understanding the GSH antioxidant system and studying some redox imbalance‐related physiological. [ABSTRACT FROM AUTHOR]

Nanochannel technology has emerged as a powerful tool for label‐free and highly sensitive detection of protein folding/unfolding status. However, utilizing the inner walls of a nanochannel array may cause multiple events even for proteins with the same conformation, posing challenges for accurate identification. Herein, we present a platform to detect unfolded proteins through electrical and optical signals using nanochannel arrays with outer‐surface probes. The detection principle relies on the specific binding between the maleimide groups in outer‐surface probes and the protein cysteine thiols that induce changes in the ionic current and fluorescence intensity responses of the nanochannel array. By taking advantage of this mechanism, the platform has the ability to differentiate folded and unfolded state of proteins based on the exposure of a single cysteine thiol group. The integration of these two signals enhances the reliability and sensitivity of the identification of unfolded protein states and enables the distinction between normal cells and Huntington's disease mutant cells. This study provides an effective approach for the precise analysis of proteins with distinct conformations and holds promise for facilitating the diagnoses of protein conformation‐related diseases. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (PQDs) have attracted much attention in the field of photoelectrochemical (PEC) sensors owing to their superb optical properties and efficient charge transport, but the inherent poor stability severely hinders their PEC applications. Herein, hydrolysis‐resistant CsPbBr3/reduced graphene oxide nanoscrolls (CsPbBr3/rGO NSs) are obtained by solvent‐assisted self‐rolling process toward water‐stable PEC sensors. CsPbBr3 QDs embedded in rGO nanosheets can be prevented from water since the multilayer rGO shell layers, which maintains excellent optical properties. On account of strong interfacial interactions, rGO nanosheets are crimped spontaneously with CsPbBr3 QDs, which offer access to superb structural and long‐term storage stability. Moreover, appropriate band alignment and ultrafast interfacial carrier transfer enable CsPbBr3/rGO NSs to exhibit greatly enhanced anode photocurrent response for subsequent PEC sensing. As a demonstration, the molecular imprinted PEC sensors for two kinds of mycotoxins (aflatoxin B1 or ochratoxin A) presents an ultra‐high sensitivity and good anti‐interference ability. Significantly, this work provides an inspirable and convenient route for hydrolysis‐resistant PQDs‐based optoelectronic and photoelectrocatalytic applications in aqueous ambience. [ABSTRACT FROM AUTHOR]

Saponins extracted from Panax notoginseng leaves by methanol or water could be orally administrated for insomnia with very low bioavailability, which might be bio‐converted by gut microbiota to generate potential bioactive products. Moreover, gut microbiota profiles from insomniac patients are very different from healthy subjects. We aimed to compare the metabolic characteristics and profiles of the two saponins extract by incubation with gut microbiota from insomniac patients. The ginsenosides, notoginsenosides, and metabolites were identified and relatively quantified by high‐performance liquid chromatography‐tandem mass spectrometry. Gut microbiota was profiled by 16S ribosomal RNA gene sequencing. The results showed that saponins were very different between methanol or water extract groups, which were metabolized by gut microbiota to generate similar yields. The main metabolites included ginsenoside Rd, ginsenoside F2, ginsenoside C‐Mc or ginsenoside C‐Y, ginsenoside C‐Mx, ginsenoside compound K, and protopanaxadiol in both groups, while gypenoside XVII, notoginsenoside Fe, ginsenoside Rd2, and notoginsenoside Fd were the intermediates in the methanol group. Moreover, the microbial, Faecalibacterium prausnitzi, could bio‐convert the saponins to obtain the corresponding metabolites. Our study implied that saponins extracted from P. notoginseng leaves by methanol or water could be used for insomniac patients due to gut microbiota biotransformation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Electrochemical sensing faces huge challenges in characterizing the transient release of biochemical molecules from deformed cells, due to the severely mechanical mismatch between rigid electrodes and soft cells. In recent years, the emergence of stretchable electrochemical sensors has made a breakthrough by complying with the deformation of living cells and simultaneous monitoring of mechanically evoked biochemical signals. This review first summarizes two fundamental strategies for the fabrication of stretchable electrodes from the points of structure and material. Next, recent progresses in construction of functionalized interface to improve the performance of stretchable electrochemical sensors are presented. Then, the application of stretchable electrochemical sensors in real‐time monitoring of biomolecules released by mechanically sensitive cells is introduced. Finally, some perspectives and challenges of stretchable electrochemical sensors regarding cell detection are discussed. What is the favorite and original chemistry developed in your research group? The design and construction of electrochemical sensing platform for real‐time monitoring of life activities. What is the most important personality for scientific research? Innovative spirit, strong curiosity and persistence. How do you supervise your students? Encourage students to think much and eager to innovate. What are your hobbies? I like music and playing badminton. Who influences you mostly in your life? My family and collaborators. Could you please give us some advices on improving Chinese Journal of Chemistry? Focusing on the originality of the manuscript. [ABSTRACT FROM AUTHOR]