Cascaded Nanozyme Based pH-Responsive Oxygenation for Targeted Eradication of Resistant Helicobacter Pylori.

Nanozymes, as substitutes for natural enzymes, are constructed as cascade catalysis systems for biomedical applications due to their inherent catalytic properties, high stability, tunable physicochemical properties, and environmental responsiveness. Herein, a multifunctional nanozyme is reported to initiate cascade enzymatic reactions specific in acidic environments for resistant Helicobacter pylori (H. pylori) targeting eradication. The cobalt-coated Prussian blue analog based FPB-Co-Ch NPs displays oxidase-, superoxide dismutase-, peroxidase-, and catalase- mimicking activities that trigger • O 2 - ${\mathrm{O}}_2^ - {\bm{\ }}$ and H2O2 to supply O2, thereby killing H. pylori in the stomach. To this end, chitosan is modified on the surface to exert bacterial targeted adhesion and improve the biocompatibility of the composite. In the intestinal environment, the cascade enzymatic activities are significantly inhibited, ensuring the biosafety of the treatment. In vitro, sensitive and resistant strains of H. pylori are cultured and the antibacterial activity is evaluated. In vivo, murine infection models are developed and its success is confirmed by gastric mucosal reculturing, Gram staining, H&E staining, and Giemsa staining. Additionally, the antibacterial capacity, anti-inflammation, repair effects, and biosafety of FPB-Co-Ch NPs are comprehensively investigated. This strategy renders a drug-free approach that specifically targets and kills H. pylori, restoring the damaged gastric mucosa while relieving inflammation.

Effective surface passivation of GaAs nanowire photodetectors by a thin ZnO capping.

The III-V nanowire (NW) structure is a good candidate for developing photodetectors. However, high-density surface states caused by the large surface-to-volume ratio severely limit their performance, which is difficult to solve in conventional ways. Here, a robust surface passivation method, using a thin layer of ZnO capping, is developed for promoting NW photodetector performance. 11 cycles of ZnO, grown on pure zinc blende high-quality GaAs NWs by atomic layer deposition, significantly alleviates the undesirable effect of the surface states, without noticeable degradation in NW morphology. An average 20-fold increase in micro-photoluminescence intensity is observed for passivated NWs, which leads to the development of detectors with high responsivity, specific detectivity, and optical gain of 9.46 × 105 A W-1, 3.93 × 1014 Jones, and 2.2 × 108 %, respectively, under low-intensity 532 nm illumination. Passivated NW detectors outperform their counterparts treated by conventional methods, so far as we know, which shows the potential and effectiveness of thin ZnO surface passivation on NW devices.

Biased agonists with less glucagon-like peptide-1 receptor-mediated endocytosis prolong hypoglycaemic effects.

Receptor endocytic trafficking entails targeting receptors and ligands to endocytic sites, followed by internalization and sorting to recycling or degradative compartments. Thus, membrane receptor-mediated signalling pathways not only contribute to the efficacy of the drugs but also play a crucial role in the metabolic elimination of peptide drugs. Glucagon-like peptide-1 (GLP-1) receptor is the crucial target for type 2 diabetes mellitus. We mainly focused on the characteristics, early evaluation of GLP-1 receptor endocytosis and effects of optimization for endocytosis on druggability. The GLP-1 receptor endocytosis characteristics of agonists were analysed by a multifunction microplate reader, flow cytometer and confocal microscope. The intracellular cyclic adenosine monophosphate (cAMP) activation of agonists was analysed based on a reporter gene assay, and intracellular ß-arrestin recruitment detection was detected based on a Tango assay. We established quantitative evaluation methods of endocytosis based on fluorescently labelled agonist and receptor trafficking and used them to screen agonists with less endocytosis. Sprague-Dawley rats were used for pharmacokinetic analyses, and the hypoglycaemic activity was evaluated by intraperitoneal glucose tolerance tests (IPGTT). Our results showed that GLP-1 receptor-mediated endocytosis, as a manner of elimination, was clathrin-dependent. More importantly, we found that agonists biased towards the G protein pathway were less endocytosed by GLP-1 receptor. We screened an analogue of Exendin-4 M4, which was biased toward the G protein pathway with less endocytosis by the GLP-1 receptor. M4, which shows prolonged hypoglycaemic activities and a long half-life, can be used as a lead compound for type 2 diabetes mellitus treatment.