A novel ratiometric sensor for fluorimetric and visual dual-mode detection of Al3+ in environmental water based on the target-regulated formation of Eu MOFs.

Herein, a novel ratiometric sensor for fluorimetric and smartphone-assisted visual detection of Al3+ in environmental water was developed based on the target-regulated formation of Eu metal-organic frameworks (Eu MOFs). By employing 2-[4-(2-hydroxyethyl) piperazin-1-yl] ethanesulfonic acid (Hepes), Eu3+ and tetracycline (TC) as raw materials, Eu MOFs with red emission were facilely synthesized through the coordination of Eu3+ with Hepes and TC. However, upon the introduction of Al3+, a higher affinity of TC towards Al3+ resulted in the formation of a TC-Al3+ complex with green fluorescence and inhibited the generation of Eu MOFs. This led to an increase in green fluorescence and a decrease in red fluorescence accompanied by the fluorescence color of the solution changing from red to green under the illumination of the UV lamp. Thus, a ratiometric sensor for fluorimetric and the smartphone-assisted visual detection of Al3+ was established. The ratiometric sensor exhibited high sensitivity for Al3+ detection with a detection limit of 0.14 µM for fluorescence detection and 1.21 µM for visual detection. Additionally, the proposed strategy was successfully applied to detect Al3+ in the environmental water samples with satisfactory results, indicating great application prospects for environmental monitoring.

Enhanced visible light photo-Fenton catalysis by Fe-doping oligo-layer natural molybdenite with efficient carrier spatial-driven Fe3+/Fe2+ cycle.

Developing cost-effective and efficient photo-Fenton catalysts is crucial for advancing photo-Fenton technology. MoS2 is a representative transition metal disulfide with attractive photoresponsiveness, making it ideal for preparing composite photo-Fenton catalysts. In this study, natural molybdenite was innovatively utilized as a source of MoS2 (OM) to synthesize a low-cost and efficient Fe@MoS2 (OMF) composite photo-Fenton catalyst by comminution and adsorption, which was then applied to the remediation of antibiotic-contaminated water. The OMF composites exhibited significant catalytic activity, with a kinetic rate constant of 0.022 min-1, which was 3.1 times higher than that of the original OM (0.007 min-1), indicating a 3% increase. This was attributed to the synergistic effect of many photogenerated electrons and reversible Mo4+/Mo6+ redox pairs, which accelerated the regeneration of Fe2+. After three cyclic tests, the concentrations of dissolved Fe2+ and Mo2+ ions remained below 0.38 mg/L and 0.17 mg/L, respectively. This indicates the high reusability of the catalyst in cyclic experiments. Ultimately, the main active species, •OH and •O2 -, were generated during the photo-Fenton process, contributing significantly to TC degradation. This study may serve as a reference for the development and application of natural mineral composite photo-Fenton catalysts in the treatment of organic wastewater.

A facile fluorescence Eu MOF sensor for ascorbic acid and ascorbate oxidase detection.

In this work, a facile fluorescence Eu3+-based metal-organic framework (Eu MOF) sensor for ascorbic acid (AA) and ascorbate oxidase (AAO) detection was developed. The fluorescence of the Eu MOF could be effectively quenched by Ce3+ but not by Ce4+ at an appropriate concentration, and thus, when the reductant AA was added into the solution containing Ce4+, Ce4+ was chemically reduced to Ce3+, which induced the decreased fluorescence signal of the Eu MOF. However, when AAO was introduced, AA was effectively oxidized to dehydroascorbic acid (DHAA) under the catalysis of AAO, and thus, Ce4+ could not be reduced, resulting in the fluorescence restoration of the Eu MOF. Hence, the concentration of AA and AAO could be determined by the fluorescence decrease and restoration of the Eu MOF. The fluorescent platform showed high sensitivity with a limit of detection of 0.32 µM for AA and 1.18 U L-1 for AAO, respectively. Moreover, the proposed method was successfully applied for AA and AAO determination in real samples, indicating great potential for biomedical application in complex matrices.

Engineered FGF19ΔKLB protects against intrahepatic cholestatic liver injury in ANIT-induced and Mdr2-/- mice model.

BACKGROUND: The major safety concern of the clinical application of wild type FGF19 (FGF19WT) emerges given that its extended treatment causes hepatocellular carcinoma. Therefore, we previously generated a safer FGF19 variant - FGF19ΔKLB, which have same effects on glycemic control and bile acid production but much less mitogenic activity. However, it remains unclear as to whether FGF19ΔKLB ameliorates intrahepatic cholestasis. RESULTS: We found that, similar to that of FGF19WT, the chronic administration of FGF19ΔKLB protects mice from cholestatic liver injury in these two models. The therapeutic benefits of FGF19ΔKLB on cholestatic liver damage are attributable, according to the following mechanistic investigation, to the reduction of BA production, liver inflammation, and fibrosis. More importantly, FGF19ΔKLB did not induce any tumorigenesis effects during its prolonged treatment. CONCLUSIONS: Together, our findings raise hope that FGF19ΔKLB may represent a useful therapeutic strategy for the treatment of intrahepatic cholestasis.

Modified In Vivo Matrix Gel Plug Assay for Angiogenesis Studies.

Several models have been developed to investigate angiogenesis in vivo. However, most of these models are complex and expensive, require specialized equipment, or are hard to perform for subsequent quantitative analysis. Here we present a modified matrix gel plug assay to evaluate angiogenesis in vivo. In this protocol, vascular cells were mixed with matrix gel in the presence or absence of pro-angiogenic or anti-angiogenic reagents, and then subcutaneously injected into the back of recipient mice. After 7 days, phosphate buffer saline containing dextran-FITC is injected via the tail vein and circulated in vessels for 30 min. Matrix gel plugs are collected and embedded with tissue embedding gel, then 12 µm sections are cut for fluorescence detection without staining. In this assay, dextran-FITC with high molecular weight (~150,000 Da) can be used to indicate functional vessels for detecting their length, while dextran-FITC with low molecular weight (~4,400 Da) can be used to indicate the permeability of neo-vessels. In conclusion, this protocol can provide a reliable and convenient method for the quantitative study of angiogenesis in vivo.