The Dual-Response-Single-Amplification Fluorescent Nanomachine for Tumor Imaging and Gastric Cancer Diagnosis.

Gastric cancer (GC) is one of the most common tumors worldwide and is the leading cause of tumor-related mortality. Traditional biomarkers and screening methods cannot meet the clinical demands. There is an urgent need for highly sensitive diagnostic markers as well as accurate quantification methods for early gastric cancer (EGC) screening.

Fishing out Methionine-Containing Proteins from Complex Biological Systems Based on a Non-Enzymatic Biochemical Reaction.

Nowadays, it still remains a great challenge to develop a simple, fast, and low-toxic method for identification and separation of proteins from complex biological systems. Herein, a nanocomposite (FeO@Au-Se-peptide) was designed and synthesized to fish out methionine-containing proteins based on a non-enzymatic biochemical reaction, which couples amino groups of lysine with the -methyl group of methionine in the presence of HOBr. Peptides which contain four lysine residues (Lys-Lys-Lys-Lys-{Se-Cys}) linked to the FeO@Au nanocomposites were used to capture methionine residues efficiently a S═N cross-linking.

Hydrogen selenide, a vital metabolite of sodium selenite, uncouples the sulfilimine bond and promotes the reversal of liver fibrosis.

Sodium selenite has alleviating effects on liver fibrosis; however, its therapeutic molecular mechanism remains unclear. Herein, hydrogen selenide, a major metabolite of NaSeO, was tested to uncouple the sulfilimine bond in collagen IV, the biomarker of liver fibrosis. A mouse model of liver fibrosis was constructed via a CCl-induced method, followed by the administration of 0.

HSe Induces Reductive Stress in HepG2 Cells and Activates Cell Autophagy by Regulating the Redox of HMGB1 Protein under Hypoxia.

Selenium has been shown to have chemotherapeutic effects against cancer. However, the anti-cancer mechanism of selenium is not fully understood, and the role of hydrogen selenide (HSe), which is a common metabolite of dietary selenium compounds, has not been elucidated due to the lack of detection methods. In this study, we revealed a new anti-cancer mechanism of selenite with the help of a HSe fluorescent probe.

Real-Time in Situ Visualizing of the Sequential Activation of Caspase Cascade Using a Multicolor Gold-Selenium Bonding Fluorescent Nanoprobe.

The caspase cascade is an ensemble of very important signaling molecules that plays a critical role in cell apoptosis. Real-time monitoring of the upstream and downstream activation relationships of the caspases in the signal pathway is of great significance for understanding the regulatory mechanisms of these signaling molecules in the development of various diseases. Herein, a multicolor fluorescent nanoprobe, GNP-Se-Casp, has been developed based on Au-Se bonding for real-time in situ monitoring caspase- (casp-) 3, 8, and 9 during cell apoptosis.

Cyclic Regulation of the Sulfilimine Bond in Peptides and NC1 Hexamers via the HOBr/HSe Conjugated System.

The sulfilimine bond (-S═N-), found in the collagen IV scaffold, significantly stabilizes the architecture via the formation of sulfilimine cross-links. However, precisely governing the formation and breakup process of the sulfilimine bond in living organisms for better life functions still remains a challenge. Hence, we established a new way to regulate the breaking and formation of the sulfilimine bond through hydrogen selenide (HSe) and hypobromous acid (HOBr), which can be easily controlled at simulated physiological conditions.

High-Quantum-Yield Mitochondria-Targeting Near-Infrared Fluorescent Probe for Imaging Native Hypobromous Acid in Living Cells and in Vivo.

The discovery that hypobromous acid (HOBr) can regulate the activity of collagen IV has attracted great attention. However, HOBr as an important reactive small molecule has hardly ever been studied using a detection method suitable for organisms. Herein, a high-quantum-yield mitochondria-targeting near-infrared (NIR) fluorescent probe for HOBr, RhSN-mito, was designed.

Highly Selective Fluorescent Probe for Imaging HSe in Living Cells and in Vivo Based on the Disulfide Bond.

Hydrogen selenide (HSe) is an important metabolite of dietary Se compounds and has been implicated in various pathological and physiological processes. The development of highly sensitive and selective methods for the sensing of HSe is therefore very important. Herein, we developed a fluorescent probe (hemicyanine (Hcy)-HSe) for detecting HSe based on a new HSe-specific receptor unit, 1,2-dithiane-4,5-diol.

An Ultrasensitive Cyclization-Based Fluorescent Probe for Imaging Native HOBr in Live Cells and Zebrafish.

Bromine has been reported recently as being the 28(th) essential element for human health. HOBr, which is generated in vivo from bromide, is a required factor in the formation of sulfilimine crosslinks in collagen IV. However, to date, no method for the specific detection of native HOBr in vivo has been reported.

A Glutathione (GSH)-Responsive Near-Infrared (NIR) Theranostic Prodrug for Cancer Therapy and Imaging.

To reduce the side effects of chemotherapy, nontoxic prodrugs activated by the tumor microenvironment are urgently required for use in cancer treatment. In this work, we developed prodrug 4 for tumor-targeting treatment and imaging of the anticancer drug release in vivo. Taking advantage of the high glutathione (GSH) concentration in cancer cells, the disulfide bond in prodrug 4 was cleaved, resulting in the release of an active anticancer drug and a near-infrared (NIR) fluorescence dye turn-on.