Latest ArticlesTumor angiogenesis is closely related to tumor development, immune escape, and drug resistance. Therefore, the development of effective anti-tumor angiogenesis drugs is of great research significance. Although the current clinical angiogenesis inhibitors have achieved certain efficacy, they also pose the problems of limited and short duration of efficacy, drug resistance, and intrinsic toxicity. Anti-tumor angiogenesis strategies targeting endothelial cells (ECs) have attracted widespread attention in the development of highly effective and low toxicity anti-angiogenesis inhibitors. Studies have verified that the trace element selenium (Se) can inhibit tumor growth by inhibiting tumor angiogenesis through different mechanisms. Nevertheless, it is unclear whether Se speciation has different effects on anti-tumor angiogenesis. Herein, we found that Se exhibited effective anti-angiogenic activity, and its mechanisms of activity were determined by its chemical speciation. Organic Se can significantly inhibit tumor angiogenesis by targeting thioredoxin reductase (TrxR) to trigger cell apoptosis and cell cycle arrest and by increasing reactive oxygen species (ROS) production in ECs. Inorganic Se can induce cell cycle arrest and increase ROS production in ECs, showing promising anti-angiogenic effects. Se nanoparticles (SeNPs) slightly inhibit tumor angiogenesis by inducing apoptosis and cell cycle arrest and by increasing the production of ROS. In summary, this study elucidates the anti-angiogenic activity of Se speciation control with a view to providing a scientific reference for the design and development of novel Se-based highly effective and low toxicity angiogenesis inhibitors.
The abuse of antibiotics has brought great harm to the human living environment and health, so it is extremely significant to develop an efficient and simple method to detect trace antibiotic residues in various wastewaters. Herein, a new two-dimensional (2D) Cd-based metal−organic framework (Cd-MOF, namely LCU-111) and its mixed matrix membranes (MMMs) is sifted as luminescence sensors for efficient monitoring antibiotic nitrofurazone (NFZ) in various aqueous systems and applied as visible fingerprint identifying. The LCU-111 has good selectivity, sensibility, reproducibility and anti-interference for luminescent quenching NFZ with low detection limits (LODs) of 0.4567, 0.3649 and 0.8071 ppm in aqueous solution, HEPES biological buffer, and real urban Tuhai River water, respectively. Interestingly, the luminescent test papers and MMMs allow the NFZ sensing easier and more rapid by naked eyes, only with a low LOD of 0.8117 ppm for MMMs sensor. Notably, by combining multiple experiments with density functional theory (DFT) calculations, the photo-induced electron transfer (PET) quenching mechanism is further elucidated. More importantly, potential practical applications of LCU-111 for latent fingerprint visualization provide lifelike evidences for effective identification of individuals, which can be applied in criminal investigation.
Condensed-phase synthesis of atomically precise clusters has become a vital branch of cluster science, where solvents are indispensable in the synthesis process. Herein, by employing the density functional theory (DFT) calculations and molecular dynamics (MD) simulations, we demonstrated that polar solvents not only provide an important environment to stabilize clusters, but they can also dramatically alter the electronic property of cluster anions forming novel superhalogen anions. Such a regulation effect was first verified in small model gas-phase pure and doped gold cluster anions, which was further evidenced in a real experimentally synthesized Au18 nanocluster. Different solvation models reveal that the solvent field, which is a noninvasive methodology different from conventional electron-counting rules, can be considered as a novel external field to remarkably increase the electron-binding capability of cluster anions while maintaining their geometrical and electronic structures. Considering the indispensability and convenient availability of the solvents, present findings may boost the potential applications of superatoms in constructing super oxidizers in the condensed phase.
A new cooperative nickel reductive catalysis and N,N-dimethylformamide-mediated strategy for umpolung C–S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides to produce alkyl aryl thioethers is described. This reaction features excellent selectivity, wide functionality tolerance, broad substrate scope, and facile late-stage modification of biologically relevant molecules. Mechanistic studies recognize initial generation of an amidyl radical anion via thermoinduced reduction of DMF with Sn, followed by umpolung reduction and single electron transfer of the nucleophilic sulfonyl moiety to form a sulphydryl radical and engage the Ni0/NiⅠ/NiⅢ/NiⅠ catalytic cycle.
Finding more effective and safe non-viral vectors to transfer genes into cancer cells has become the key of immune gene therapy for cancer. Herein a triblock compound MPEG2000–PDLLA4000–MPEG2000 modified by cationic liposome DOTAP was used as a non-viral vector DOTAP/MPEG2000–PDLLA4000–MPEG2000 (DMPM) to effectively transfer interleukin (IL)-12 plasmid (pIL-12) into tumor tissue. IL-12 produced by transfected tumor cells successfully inducing lymphocyte proliferation and promoting interferon-γ (IFN-γ) secretion, which resulted in tumor cells death. The ability of DMPM to transfer pIL-12 and the immune effect induced by IL-12 in cells had been explored. The anti-tumor effect, mechanism and safety of pIL-12/DMPM in mice cancer model were investigated in this study. Our results showed that the pIL-12 transferred by DMPM was highly expressed both in CT26 cells and B16-F10 cells. IL-12 expressed in the culture supernatant of transfected tumor cells stimulated lymphocyte proliferation and promoted IFN-γ secretion. The experimental result confirmed that pIL-12/DMPM therapy significantly reduced tumor growth in mice model. We designed the nanocomposite DMPM to deliver pIL-12 for cancer treatment and explored its therapeutic efficacy and the underlying anti-tumor mechanism. Our study suggested pIL-12 loaded by DMPM complex would be an effective strategy for cancer treatment.
Direct synthesis of H2O2 from H2 and O2 via heterogeneous catalysis is an environmentally friendly and atomically economic alternative to the traditional anthraquinone oxidation (AO) process. Optimizing the electronic and geometric structures of the active metals to break the current limitations of hydrogenation rate and H2O2 selectivity is a promising and challenging topic. In this study, a series of Pd-Au bimetallic catalysts supported on TiO2 with a metal loading of 3.0 wt% and a constant Pd/Au molar ratio (Pd:Au = 2:1) were prepared. The catalysts were reduced in H2 at different temperatures (473, 573 and 673 K), and their catalytic activity for the direct H2O2 synthesis were evaluated at 283 K and 0.1 MPa. H2 reduced Pd-Au catalysts exhibited superior performance in direct H2O2 synthesis. The maximum H2O2 selectivity of 87.7% and H2O2 yield of 3116.4 mmol h−1 gPd−1 were achieved over the Pd2.0Au1.0-573 catalyst with a H2 conversion of 12.8%. The tailored local chemical environment caused by H2 reduction creates a balanced ratio of Pd0 and PdOx sites, thus improving the selectivity towards H2O2. This work developed an effective strategy for fabrication of highly active and stable Pd-based H2O2 synthesis catalysts with high H2O2 yield.
Molybdenum disulfide (MoS2) has shown significant promise as an economic hydrogen evolution reaction (HER) catalyst for hydrogen generation, but its catalytic performance is still lower than noble metal-based catalysists. Herein, a silver nanoparticles (Ag NPs)-decorated 1T/2H phase layered MoS2 electrocatalyst grown on titanium dioxide nanorod arrays (Ag NPs/1T(2H) MoS2/TNRs) was prepared through acid-tunable ammonium ion intercalation. Taking advantage of MoS2 layered structure and crystal phase controllability, as-prepared Ag NPs/1T(2H) MoS2/TNRs exhibited ultrahigh HER activity. As-proposed strategy combines facile hydrogen desorption (Ag NPs) with efficient hydrogen adsorption (1T/2H MoS2) effectively circumventes the kinetic limitation of hydrogen desorption by 1T/2H MoS2. The as-prepared Ag NPs/1T(2H) MoS2/TNRs electrocatalyst exhibited excellent HER activity in 0.5 mol/L H2SO4 with low overpotential (118 mV vs. reversible hydrogen electrode (RHE)) and small Tafel slope (38.61 mV/dec). The overpotential exhibts no obvious attenuation after 10 h of constant current flow. First-principles calculation demonstrates that as-prepared 1T/2H MoS2 exhibit a large capacity to store protons. These protons can be subsequently transferred to Ag NPs, which significantly increases the hydrogen coverage on the surface of Ag NPs in HER process and thus change the rate-determining step of HER on Ag NPs from water dissociation to hydrogen recombination. This study provides a unique strategy to improve the catalytic activity and stability for MoS2-based electrocatalyst.
Anti-counterfeiting labels with various fluorescent colors are of great importance in information encryption-decryption, but are still limited to static information display. Therefore, it is urgent to develop new materials and encryption-decryption logic for improving the security level of secret information. In this study, an organohydrogel made up of poly(N,N-dimethylacrylamide) (pDMA) hydrogel network and polyoctadecyl methacrylate (pSMA) organogel network that copolymerized with two fluorophores, 6-acrylamidopicolinic acid moieties (6APA, fluorescent ligand) and spiropyran units (SPMA, photochromic monomer), was prepared by a two-step interpenetrating method. As UV light of 365 nm and 254 nm can both cleave Cspiro-O bonds of SPMA, and the green fluorescence of 6APA-Tb3+ can only be excited by 254 nm light, the organohydrogel displays yellow and red under the irradiation of 254 nm and 365 nm, respectively. In addition to wavelength selectivity, these two fluorophores are thermal-responsive, leading to the fluorescence variation of the organohydrogel during heating process. As a result, secret information loaded on the organohydrogel can be decrypted by the irradiation of UV light, and the authenticity of the information can be further identified by thermal stimulation. Our fluorescent organohydrogel can act as an effective anti-counterfeiting label to improve the information security and protect the information from being cracked.
The rational construction of high-performance and stable electrocatalyst for oxygen evolution reaction (OER) is a prerequisite for efficient water electrolysis. Herein, we develop a broccoli-like Ni3S2@NiFePx (Ni3S2@NFP) catalyst on nickel foam (NF) via a sequential two-step layer-by-layer assembly electrodeposition method. X-ray diffraction, in situ Raman and Fourier-transform infrared spectra have mutually validated the element segregation and phase refusion during OER condition. The reconstruction of double layer Ni3S2@NFP facilitates the formation of the active (oxy)hydroxides, which is modulated by the dual anionic layer with mixed sulfate and phosphate ions. As a result, the obtained Ni3S2@NFP electrode exhibits low overpotential (329 mV) and long-term durability (~500 h) for OER at current density of 500 mA/cm2. Moreover, the self-supported Ni3S2@NFP can act as an efficient and durable anode in alkaline anion exchange membrane water electrolysis device (AEMWE). This work provides a facile and scaled-up strategy to construct self-supported electrocatalyst and emphasizes the crucial role of anions in pre-catalyst reconstruction and enhancing OER performance.
The transport of colloids and radionuclides is sophisticated because of the variety of charge properties between colloidal particles and host subsurface media, which causes great difficulty in establishing a reliable model of radionuclides migration by taking the colloid phase into consideration. In this work, the co-transport of illite colloids (IC) and Eu(Ⅲ) in the quartz sand and iron-coated sand porous media was investigated by column experiments to address the predominant mechanism of charge properties on co-transport. Results showed that Eu(Ⅲ) transport was driven by the illite colloids and electrostatic interaction was critical in governing the co-transport patterns. The promotion of Eu(Ⅲ) transport by IC was attenuated in the iron-coated sand systems; more IC-Eu(Ⅲ) complexes were retained uniformly in the column. The pore throat shrinkage caused by electrostatic attachment between aggregated IC and iron oxides exacerbated the physical straining and size exclusion effect of IC-Eu(Ⅲ) complexes. An aggravated irreversible retention of IC-Eu(Ⅲ) was detected in iron-coated sand column due to the electrostatic attraction of IC-Eu(Ⅲ) to host media. The findings are essential for improving the understanding on the potential transport, retention and release risk of colloids associated radionuclides, and imply that the positively charged permeable reactive barrier is an effective strategy to reduce the transport risk of colloid associated radionuclides.
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