Latest ArticlesExosomal microRNA (miRNA) is an ideal candidate of noninvasive biomarker for the early diagnosis of cancer. Sensitive and accurate sensing of abnormal exosomal miRNA plays essential role for clinical promotion due to its close correlation with tumor proliferation and progression. Herein, a microfluidic surface-enhanced Raman scattering (SERS) sensor was proposed for an on-line detection of exosomal miRNA based on rolling circle amplification (RCA) and tyramine signal amplification (TSA) strategy. The microfluidic chip consists of a magnetic enrichment chamber, a serpentine fluidic mixer and a plasmonic SERS substrate functionalized with capture probes. The released miRNA activates the capture probe, triggers RCA reaction, and generates a large number of single-stranded DNA products to drive the catalysis of nanotags deposition via TSA, producing numerous phot spotsq to enhance the SERS signals. In merit of the microfluidics chip and nucleic acid-tyramine cascade amplification, the developed SERS sensor significantly improves the sensitivity for the exosomal miRNA assay, resulting in a limit of detection (LOD) as low as 1 pmol/L and can be successfully applied in the analysis of exosomes secreted from breast tumor cells, which demonstrates the potential utility in practical applications.
In this study, Ag0.23/(S1.66-N1.91/TiO2-x) single-atom photocatalyst was synthesized by in-situ photo-reducing of silver on S, N-TiO2-x nanocomposite and used to degrade bisphenol A (BPA) through heterogeneous activation of potassium peroxymonosulfate (PMS) under visible-light illumination. The structure, physicochemical property, morphology, and electronic property were evalutated by X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectra (XPS), high-resolution transmission electron microscopy (HR-TEM), UV–vis diffuse reflectance spectra (UV-vis DRS), electron paramagnetic resonance (EPR) spectrum. Ag0.23/(S1.66-N1.91/TiO2-x) single-atom photocatalyst exhibited 2.4 times higher activity for the synergetic degradation of BPA than that of its counterpart, and 48.73% mineralization rate of BPA also achieved. It was ascribed to the uniformly-dispersed metallic Ag atoms as the active site for accelerating the migration rate of photo-generated carrier for generation of high reactive radicals. The EPR experiments indicated that SO4•‒ and •OH was jointly involved in BPA degradation.
Alcohol consumption is a critical risk factor contributing to a verity of human diseases. The incidence of alcohol use disorder increases across adolescence in recent years. Accumulating line of evidence suggests that alcohol-induced changes of DNA cytosine methylation (5-methyl-2'-deoxycytidine, 5mC) in genomes play an important role in the development of diseases. However, systemic investigation of the effects of adolescent alcohol exposure on DNA and RNA modifications is still lacked. Especially, there hasn't been any report to study the effects of alcohol exposure on RNA modifications. Similar to DNA modifications, RNA modifications recently have been identified to function as new regulators in modulating numbers of biological processes. In the current study, we systematically investigated the effects of alcohol exposure on both DNA and RNA modifications in peripheral blood of adolescent rats by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. The developed LC-ESI-MS/MS method enabled the sensitive and accurate determination of 2 DNA modifications and 12 RNA modifications. As for the alcohol exposure experiments, the adolescent rats were intraperitoneally injected with ethanol with an interval of one day for a total 14 days. The quantification results by LC-ESI-MS/MS analysis showed that adolescent alcohol exposure could alter both DNA and RNA modifications in peripheral blood. Specifically, we observed an overall decreased trend of RNA modifications. The discovery of the significant alteration of the levels of DNA and RNA modifications under alcohol exposure indicates that alcohol consumption may increase the risk of the incidence and development of diseases through dysregulating DNA and RNA modifications.
Azulene, one of representative nonbenzenoid aromatic hydrocarbons, exhibits unique molecular structure and distinctive physical and chemical properties. Herein, azulenoisoindigo (AzII), an azulene-based isoindigo analogue, is designed and synthesized, which has a twisted molecular backbone and R/S-isomers in single crystals. Interestingly, AzII shows the characteristics of both isoindigo and azulene, such as reversible redox behavior and reversible proton responsiveness. UV-vis-NIR, 1H NMR and electron paramagnetic resonance (EPR) measurements were carried out to get insights into the possible mechanism of the proton-responsive property of AzII. The results demonstrated that only one azulenyl moiety of molecule of AzII was protonated and deprotonated, and the protonated AzII can be further oxidized to form azulenium cation radicals.
Transition metal-based bimetallic oxides can effectively activate peroxymonosulfate (PMS) for the degradation of organic contaminants, which may be attributed to the enhanced electron transfer efficiency between transition metals. Here, we investigated the high-efficiency catalytic activation reaction of PMS on a well-defined bimetallic Fe-Mn nanocomposite (BFMN) catalyst. The surface topography and chemical information of BFMN were simultaneously mapped with nanoscale resolution. Rhodamine B (RhB, as a model pollutant) was used to evaluate the oxidation activity of PMS activation system. The maximum absorption peak of RhB obviously blue shifted from 554 nm to 501 nm, and decreased sharply to disappear completely within 60 min. The removal performance is better than most of the reported single transition metal oxide. X-ray photoelectron spectroscopy (XPS) imaging of the BFMN electronic structure after catalytic activation confirmed that the accelerated internal electron transfer is mainly caused by the synergy effect of Mn and Fe sites at the catalysis boundary. The outstanding ability of BFMN for PMS chemical adsorption and activation may attribute to the enhanced covalency and reactivity of Mn-O. These results of this study can advance understandings on the origins of bimetallic oxides activity for PMS activation and developing the efficient metal oxide catalysts in real practice.
Metal-organic frameworks (MOFs) as a type of crystalline heterogeneous catalysts have shown potential application in photocatalytic CO2 reduction. However, MOF catalysts with high efficiency and selectivity are still in pursuit. Herein, by a bimetallic strategy, the catalytic performance of a Co-MOF for photocatalytic CO2 reduction was enhanced. Specifically, the Co-MOF based on 4, 5-dicarboxylic acid (H3IDC) and 4, 4ʹ-bipydine (4, 4ʹ-bpy) can catalyze CO2 reduction to CO, with high efficiency but relatively low selectivity. After replacement of 2/3 Co(Ⅱ) with Ni(Ⅱ) within Co-MOF, the resulted isostructural Co1Ni2-MOF not only retains high efficiency for photocatalytic CO2 reduction, but also shows enhanced CO selectivity. The CO evolution rate reaches 1160 µmol g−1 h−1 and the CO selectivity reaches as high as 94.6%. The enhanced photocatalytic CO2 reduction performance is supported by theoretical calculation results. This case demonstrates that bimetallic strategy is an effective mean to optimize the catalytic performance of MOF catalysts for photochemical CO2 reduction.
Pharmaceutical salt formation is the most preferred and effective method to enhance the physicochemical properties of APIs. The aim of the study was to design and synthesize a series of new salts to improve the solubility of Imatinib (IM). Two stable salts with malonic acid (S1) and citric acid (S5), one metastable salt with fumaric acid (S2), two unstable salts with citric acid (S3, S4) were obtained for the first time. Single crystal and powder X-ray diffraction, Fourier transform infrared, differential scanning calorimetry, and thermogravimetric analysis were used to characterize the novel salts. The solubility and stability of the solid were also evaluated, and three salts (S1, S2, S5) had a more than 20 folds of solubility and a faster dissolution rate improved as compared to the pure drug in water and pH 6.8 buffer, respectively.
Herein, we presented a novel biodegradable copolymer via the chain extending reaction of poly(p-dioxanone)-co-poly(2-(2-hydroxyethoxy) benzoate) (PPDO-co-PDHB) prepolymer with hexamethylene diisocyanate (HDI) as a chain extender. The structures and molecular weight of PPDO-co-PDHB prepolymer and PPDO-co-PDHB-PU chain-extended copolymer are characterized via hydrogen nuclear magnetic resonance spectroscopy (1H NMR) and viscosity test. The relationship between the molecular structures and properties of the chain-extended copolymers is established. The PPDO-co-PDHB-PU copolymers possess a better thermal stability comparing with the PPDO homopolymer. The study of mechanical properties shows that the elongation-at-break of PPDO-co-PDHB-PU is much higher than that of PPDO. The investigation of hydrolytic degradation behaviors indicates the degradation rate of PPDO can be controlled by adjusting the PDHB compositions, and proves that chain-extended copolymers exhibit an excellent hydrolytic stability being better than that of PPDO.
Carbon nanotube-based (CNT-based) interfacial evaporation material is one of the most potential materials for solar desalination. Here, we studied the evaporation rate of the CNT-based membranes with different hydrophilic and hydrophobic chemical modified surfaces using molecular dynamic simulations. We found that the hydrogen bonding density among water molecules at the interface is a key factor in enhancing the evaporation rate. For a hydrophilic CNT-based membrane, the strong interactions between the membrane outer surface and the water molecules can destroy the water-water hydrogen bonding interactions at the interface, resulting in the reduction of the hydrogen bonding density, leading to an enhancement effect in evaporation rate. We also found that there is an optimal thickness for evaporation membrane. These findings could provide some theoretical guidance for designing and exploring advanced CNT-based systems with more beneficial performance in water desalination.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
