Magnetic Cu/Fe3O4@FeOOH with intrinsic HRP-like activity at nearly neutral pH for one-step biosensing.

The convenience of colorimetric sensors is useful for practical applications. In this work, we constructed a novel colorimetric sensor with magnetic separation ability that can be operated in nearly neutral conditions and achieve one-step detection of metabolites. Magnetic Cu doped Fe3O4@FeOOH magnetic nanocomposite (Cu/Fe3O4@FeOOH) with an oxygen vacancy was prepared by a one-step self-assembly hydrothermal method, and fully characterized by different methods. The oxygen vacancy generated by the incorporation of Cu2+ cations into the Fe3O4@FeOOH structure was confirmed to be a vital reactive site for enhancing the catalytic activity, which opens up a new way of designing highly efficient enzyme mimics. Benefiting from its inherent horseradish-peroxidase-like activity, a simple and selective enzyme-based colorimetric sensor was developed for one-step detection of H2O2 and cholesterol, and 3,3',5,5'-tetramethylbenzidine was catalyzed by H2O2 to generate a colored product of oxidized 3,3',5,5'-tetramethylbenzidine for signaling. H2O2 and cholesterol can be linearly detected in the same range from 0.01 to 0.4 mmol L-1 with detection limits of 0.0075 mmol L-1 and 0.0082 mmol L-1, respectively. The proposed colorimetric sensor has satisfactory reusability, accuracy, and practicability in human serum samples, indicating its potential application for the detection of different metabolites in the fields of life science and analytical science. Graphical abstract.

Fungal co-infection in COVID-19 patients: evidence from a systematic review and meta-analysis.

Coronavirus disease 2019 (COVID-19) has infected tens of millions of people worldwide within the last year. However, the incidence of fungal co-infection in COVID-19 patients remains unclear. To investigate the association between fungal co-infection and mortality due to COVID-19, we systematically searched Medline, Embase, MedRxiv and Cochrane Library for eligible studies published in the period from 1 January to 1 December 2020. We performed a meta-analysis of nine studies that met the inclusion criteria. In total, data from 2780 patients and 426 patients were included who were admitted to the ICU. In eight of the articles, 211 participants died due to COVID-19 infection, which means an overall mortality rate of 10.9%. The overall pooled proportion of fungal co-infection in COVID-19 patients was 0.12 (95% CI = 0.07-0.16, n = 2780, I2 = 96.8%). In terms of mortality in COVID-19 patients with fungal infection, the overall pooled proportion of mortality was 0.17 (95% CI = 0.10-0.24, n = 1944, I2 = 95.6%). These findings provide evidence suggesting a favorable use for empirical antibiotics in the majority of patients when COVID-19 infection is diagnosed. Our analysis is investigating the use of antifungal therapy to treat COVID-19 can serve as a comprehensive reference for COVID-19 treatment.

Mechanism of Action of Periplogenin on Nasopharyngeal Carcinoma Based on Network Pharmacology and Experimental Study of Vitamin E Coupled with Periplogenin Self-Assembled Nano-Prodrug for Nasopharyngeal Carcinoma.

Periplogenin is a compound extracted from cortex periplocae. In the monomers' screening for inhibiting nasopharyngeal carcinoma, we found that periplogenin can inhibit nasopharyngeal carcinoma; however, its mechanism is still unclear. In this study, the chemical structure of periplogenin was uploaded to the PubChem database in order to obtain the target of periplogenin. The NPC's differential genes were obtained by analyzing the nasopharyngeal carcinoma data in the GEO database by R software. The common target of periplogenin and nasopharyngeal carcinoma was obtained through Cytoscape. Through R software analysis, ALB, epidermal growth factor receptor (EGFR), MAPK1, ESR1, MAPK8, SRC, CASP3, HSP90AA1, AR, MAPK14 may be the main targets of periplogenin in NPC. Through go enrichment analysis, it was found that periplogenin acted mainly on nasopharyngeal carcinoma through response to steroid metabolic process, cellular response to steroid hormone stimulus, hormone-mediated, and steroid hormone signaling pathway. After enrichment analysis on the Kyoto Encyclopedia of Genes and Genomes pathway, it was found that periplocan may inhibit NPC through the MAPK signaling pathway (the main signaling pathway), and the signaling pathway of proteoglycans in cancer, and the PI3K/AKT signaling pathway as well. In this study, we also carried out the experimental study of vitamin E together with periplogenin self-assembled nano-prodrugs in the treatment of NPC, and the results showed that tumor weight of PBS group was 0.531±0.039 g, while that of PPG group and MPSSV-NPs group was 0.258±0.059 g and 0.169±0.033 g, respectively, which was lower than PBS group. And the tumor inhibition rate of MPSSV-NPs was 69.41%, which was significantly higher than that of the PPG group (51.38%). This study demonstrated the mechanism of inhibition of nasopharyngeal carcinoma (NPC) by the monomer of periplogenin based on network pharmacology. We preliminarily confirmed that vitamin E coupled with a periplogenin self-assembled nano-prodrug has obvious effect in treating nasopharyngeal carcinoma.