Latest ArticlesFluorescent materials that respond to multiple stimuli have broad applications ranging from sensing and bioimaging to information encryption. Herein, we report the design and synthesis of a single-fluorophore-based amphiphile DCSO, which shows temperature-, solvent-, humidity-, and radiation-dependent fluorescence. DCSO consists of a dicyanostilbene (DCS) group as a rigid hydrophobic core with oligo(ethylene glycol) (OEG) chains at both ends as a flexible hydrophilic periphery. The DCS group acts as a highly efficient fluorophore, while the OEG chain endows the molecule with thermo-responsiveness. Fluorescent colors can vary from blue to green to yellow in response to external stimuli. On the basis of light radiation, we demonstrate that this system can be applied to time-dependent information encryption, in which the correct information can only be read at a specific time under irradiation. This work further demonstrates the usefulness and application of single-fluorophore-based luminescent materials with multiple stimuli-responsive functions.
Silver selenide thin film is one of the best candidates for thermoelectric devices. In the previous report, we demonstrated that high-performanced [201] oriented β-Ag2Se thin films can be prepared by direct metal surface element reaction (DMSER) solution selenization in a really short time at room temperature. However, the underlying mechanism of the fast reaction process were not discussed in depth. Herein, based on hard soft acid base (HASB) theory and strong oxidation, we further explored the possible reaction mechanism of the in-situ growth of β-Ag2Se thin films as the function of the reaction time. The time-dependent experimental results showed that the formation of the β-Ag2Se on elemental Ag precursor (~690 nm thick) in Se/Na2S precursor solution is in a growth driven mode with no obvious orientation or growth rate selections to the elemental Ag precursors. Our investigations provide a prerequisite for the further preparation of thermoelectric materials with excellent properties.
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.
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.
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.
To address the insulating nature and the shuttle effect of iodide species that would deteriorate the battery performance, herein iron nitride is well-dispersed into porous carbon fibers with good flexibility via the facile electrospinning method and subsequent pyrolysis. The polyacrylonitrile precursor introduces the nitrogen doping under thermal treatment while the addition of iron acetylacetonate leads to the in-situ formation of iron nitride among the carbon matrix. The crucial pyrolysis procedure is adjustable to determine the hierarchical porous structure and final composition of the novel carbon fiber composites. As the self-supporting electrode for loading iodine, the zinc-iodine battery exhibits a large specific capacity of 214 mAh/g and good cycling stability over 1600 h. In the combination of in-situ/ex-situ experimental measurements with the theoretical analysis, the in-depth understanding of intrinsic interaction between composited support and iodine species elucidates the essential mechanism to promote the redox kinetics of iodine via the anchoring effect and electrocatalytic conversion, thus improving cycling life and rate performance. Such fundamental principles on the basic redox conversion of iodine species would evoke the rational design of advanced iodine-based electrodes for improving battery performance.
Flexible electronics technology is considered as a revolutionary technology to unlock the bottleneck of traditional rigid electronics that prevalent for decades, thereby fueling the next-generation electronics. In the past few decades, the research on flexible electronic devices based on organic materials has witnessed rapid development and substantial achievements, and inorganic semiconductors are also now beginning to shine in the field of flexible electronics. As validated by the latest research, some of the inorganic semiconductors, particularly those at low dimension, unexpectedly exhibited excellent mechanical flexibility on top of superior electrical properties. Herein, we bring together a comprehensive analysis on the recently burgeoning low-dimension inorganic semiconductor materials in flexible electronics, including one-dimensional (1D) inorganic semiconductor nanowires (NWs) and two-dimensional (2D) transition metal dichalcogenides (TMDs). The fundamental electrical properties, optical properties, mechanical properties and strain engineering of materials, and their performance in flexible device applications are discussed in detail. We also propose current challenges and predict future development directions including material synthesis and device fabrication and integration.
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.
Kirsten rat sarcoma viral oncogene homolog (KRAS)–phosphodiesterase-delta (PDEδ) is a promising target for antitumor drug discovery. Herein, highly efficient and environmentally sensitive fluorescent probes of PDEδ (DS-Probes) were rationally designed. As compared with the reported PDEδ probes, DS-Probes showed higher binding affinity and selectivity, which were able to conveniently and efficiently label PDEδ in live cells as well as tumor tissues. Therefore, these fluorescent probes are expected to facilitate PDEδ-based mechanism elucidation, drug discovery and pathologic diagnosis.
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.
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