Latest ArticlesMicroscale zero valent iron (mFe0) is one of the most potential water pollution remediation materials, but the effective utilization ability of electrons released by mFe0 in the reduction of hexavalent chromium (Cr(Ⅵ)) is not satisfactory. Here, we find the microscale iron-copper (mFe/Cu) bimetals coated with copper on the surface of mFe0 can significantly improve the effective utilization of electrons released by mFe0. Electrochemical analysis displays that copper plating on the surface of mFe/Cu can promote the release the electrons from mFe0 and reduce the impedance of mFe0. Spin-polarized density functional theory (DFT) calculation reveals that Cu on the surface of mFe/Cu bimetals promotes the release of electrons from mFe0 and reduces the adsorption energy of Fe to Cr. As the electron transporter, moreover, Cu can always attract Cr to the hollow position near itself of the Fe surface, which could promote the effective utilization of electrons released by Fe. Effective utilization ability of electrons in mFe/Cu system is 12.5 times higher than that in mFe0 system. Our findings provide another basis for the efficient reduction of Cr(Ⅵ) by mFe/Cu bimetals, which could promote the application and popularization of mFe/Cu bimetals.
In the context of the circular economy, the huge amounts of biomass waste should be converted into value-added materials and energy to diminish pollution, atmospheric CO2 levels and costly waste disposal. Biological imaging usually uses expensive and toxic chemicals e.g., organic dyes, semiconductor quantum dots, calling for safer, greener, cheaper fluorescent probes for biological imaging in vitro and in vivo. In these regards, carbon quantum dots (CQDs)-based fluorescent probes using biomass waste as a precursor may have much higher potential. Here we transformed the biomass waste of peach leaves into value-added fluorescent CQDs through a low-cost and green one-step hydrothermal process. The obtained CQDs show excitation-dependent photoluminescence properties with a fluorescence lifetime of 5.96 ns and a quantum yield of 7.71% without any passivation. In addition, the CQDs have a fine size of 1.9 nm with good hydrophilicity and high fluorescent stability over pH 4.0–11.0 range. Fluorescence imaging of in vitro cell cultures and in vivo with zebrafish show that CQDs possess ultra-low toxicity and remarkable performance for biological imaging. Even when CQDs present at a concentration as high as 500 µg/mL, the organism can still maintain more than 90% activity both in vitro and in vivo, and present bright fluorescence. The cheaper, greener, ultra-low toxicity CQDs developed in this work is a potential candidate for biological imaging in vitro and in vivo.
Extracellular vesicles (EVs) are cell-derived nanosized vesicles widely recognized for their critical roles in various pathophysiological processes. Molecular analysis of EVs is currently being considered an emerging tool for diseases diagnosis. However, the small size and heterogeneity of EVs has staggered the EVs research for diseases diagnosis. DNA nanotechnology enables self-assembly of versatile DNA nanostructures and has shown enormous potential in assisting EVs biosensing. In this review, we briefly introduce the recent advances in DNA nanotechnology approaches for EVs detection. The approaches were categorized based on the dimension of DNA nanostructures. We provide critical evaluation of these approaches, and summarize the pros and cons of specific methods. Further, we discuss the challenges and future perspectives in this field.
Bicyclic peptides, a class of polypeptides with two loops within their structure, have emerged as powerful tools in the development of new peptide drugs. They have the potential to bind to challenged drug targets, with antibody-like affinity and selectivity. Meanwhile, bicyclic peptides possess small molecule-like access to chemical synthesis, which is conducive to large-scale synthesis and screening. In the last five years, bicyclic peptide technology has been increasingly developed, and researchers have carried out a variety of studies to elucidate the potential functions of bicyclic peptides. With the continuous development of synthetic methods and the advances of new technology to build bicyclic peptide libraries, bicyclic peptides are now becoming widely used in the development of new drugs for various diseases. This perspective provides an overview of the structure types, synthesis and applications of bicyclic peptides in current drug development, and our own views on future challenges of bicyclic peptides.
Ibrutinib is a first-line treatment drug for B-cell malignancies. However, resistance to ibrutinib has been reported due to BTKC481S mutation. Although PROTAC strategy is expected to overcome this clinical resistance, it has limitations such as large molecular weight and moderate bioactivity, which restrict its potential clinical application. Herein, we report a new type of potent BTKC481S-targeting PROTAC degrader. Through design, computer-assisted optimization and SAR studies, we have developed a representative BTKC481S degrader L6 with a much smaller molecular weight and improved solubility. Notably, L6 demonstrates better BTK degrading activity and lower IC50 value in ibrutinib-resistant cell line than the first-generation BTK degrader P13I. Optimization strategy of L6 provides a general approach in the development of PROTACs targeting BTK and other proteins for future study.
A novel route of enzalutamide was developed in five steps. Starting from 4-amino-2-(trifluoromethyl)benzonitrile (7) and Boc-2-aminoisobutyric acid (16), condensation, deprotection, Ullmann coupling, cyclization and amination provided enzalutamide in 41.0% total yield. This route avoids the using of toxic chemical, unstable intermediate and high-risk reaction. It is a potential efficient and economical procedure for industrialization.
The Ni−Al bimetallic catalysis of intramolecular enantioselective and regioselective C−H cyclization of 4-oxoquinazolines with tethered alkenes has been successfully developed. Some new secondary phosphine oxides (SPOs) with large steric hindrance (SPO6-11) were designed and successfully synthesized from readily available chiral amines or amino acids. The developed chiral SPOs as ligands or preligands demonstrate much higher efficiency in the asymmetric catalytic reactions than the reported traditional ones. A new class of chiral tricyclic pyrroloquinazolinones were obtained in up to 95% yield and 99% ee.
Due to its difficulty and complexity, the cleavage and subsequent functionalization of the C(sp3)-C(sp3) single bond has received less attention than the CC bond formation reactions that have been extensively studied. Herein, by utilizing Cu/g-C3N4 nanometric semiconductor as a recyclable photocatalyst, an aerobic oxidative CC bond cleavage of aldehydes was developed with the promotion of amines under visible light irradiation. Based on the reaction, phenylacetaldehyde was selected as a highly efficient formylation reagent for amines. Under blue light irradiation, good to excellent yields of formamides were achieved for various amines in 1 atm oxygen atmosphere at room temperature. This methodology offers a practical, neutral and gentle alternative to the preparation of formamides.
A facile and elegant method for synthesis of novel N–aryl phenothiazine derivatives from 2-phenylindolizines and phenothiazines through direct electrochemical oxidation has been developed. This approach was performed smoothly at room temperature without external oxidant and catalyst. Cyclic voltammetry and in situ FTIR techniques were applied to analyze the cross-coupling process of phenothiazines and 2-phenylindolizines, which helped to select the appropriate reaction potential. Under the optimized conditions, a broad range of substrates were well tolerated, affording the desired products in moderate to excellent isolated yields (up to 91%) with high regioselectivity. Meanwhile, a plausible mechanism involving a radical pathway has been proposed.
The lantern-shaped cage Pd2L4 and tweezer-like PdL2 can be synthesized from the trans- and cis-isomer of an azobenzene-containing ligand, respectively, which were characterized by 1H, 13C, 1H-1H COSY, DOSY NMR spectroscopies, high-resolution ESI-MS and density function theory (DFT) calculations. The interconversion of Pd2L4 and PdL2 can be achieved via the cis-trans isomerization of the azobenzene unit on the ligand upon alternative irradiation of light 365 nm or 420 nm.