Latest ArticlesMonitoring α-glucosidase (α-Glu) activity is of great significance for the early diagnosis of type II diabetes. Here the blue fluorescent carbon dots (CDs) were integrated with two different recognizing molecules, β-cyclodextrin and phenylboronic acid, for assembling a multifunctional CDs (mCDs) nanoplatform for sensitively analyzing α-Glu and its inhibitors. The hydrolyzed product of 4-nitrophenyl-α-d-glucopyranoside (α-Glu substrate), p-nitrophenol, could efficiently quench the fluorescence of mCDs due to its cooperative molecular recognition with β-cyclodextrin and phenylboronic acid. The mCDs could be utilized for the detection of α-Glu activity with the limit of detection of 0.030 U/L. Moreover, the present α-Glu detection platform revealed a high selectivity, and other natural enzymes showed scarcely any effect on the present mCDs system. The proposed method could be facilely used to screen α-Glu inhibitors with satisfying performance. The rational mCDs is expected to supplement more comprehensive biosensing platforms for highly sensitive and specific recognition of disease-relevant biomarkers with clinical importance.
Bare Pd metal nanoparticles invariably suffer from poor selectivity in furfural hydrogenation by forming flat configurations, with the aromatic ring of the substrate molecules parallel to the metal surface. Herein, we put forward a promising solution by using CeO2 as promoters to modify Pd nanoparticles for modulating the adsorption behaviors of furfural molecules. To achieve the highly-desired ultra-small Pd@CeO2 core@shell nanostructure, a "constrained auto-redox" synthesis is developed, in which silicalite-1 supports play the key role of providing their surface as the landing place of PdOx precursors for inhibiting the overgrowth and the deformation. To the best of our knowledge, this is one of the smallest core@shell materials obtained from aqueous synthesis. When evaluated as catalysts, Pd@CeO2/S-1 gives 98.9% conversion of furfural with 94.3% selectivity for furfural alcohol in 15 h, which is much better than that of Pd/S-1 (88.6% conversion with 44.3% selectively). The DFT simulation reveals a strong interaction between the defects of CeO2 and the oxygen atom of the –CHO group in furfural molecules, which benefits the selective hydrogenation occurred in the –CHO group rather than the furan ring.
Optical thermometry as an important local temperature-sensing technique, has received increasing attention in scientific and industrial areas. However, it is still a big challenge to develop luminescent materials with self-activated dual-wavelength emissions toward high-sensitivity optical thermometers. Herein, a novel ratiometric thermometric strategy of Bi3+-activated dual-wavelength emission band was realized in the same lattice position with two local electronic states of La3Sb1-xTaxO7:Bi3+(0 ≤ x ≤ 1.0) materials based on the different temperature-dependent emission behaviors, benefiting from the highly-sensitive and regulable emission to the coordination environment of Bi3+. The structural and spectral results demonstrate that the emission tremendously shifted from green to blue with 68 nm and the intensity was enhanced 2.6 times. Especially, the visual dual-wavelength emitting from two emission centers was presented by increasing the Ta5+substitution concentration to 20% or 25%, mainly originating from the two local electronic states around the Bi3+ emission center. Significantly, the dual-wavelength with different thermal-quenching performance provided high-temperature sensitivity and good discrimination signals for optical thermometry in the range between 303 and 493 K. The maximum relative sensitivity reached 2.64%/K (La3Sb0.8Ta0.2O7:0.04Bi3+@383 K) and 1.91%/K (La3Sb0.75Ta0.25O7:0.04Bi3+@388 K). This work reveals a rational design strategy of different local electronic states around the single-doping multiple emission centers towards practical applications, such as luminescence thermometry and white LED lighting.
Two 3d-4f-5d heterometallic cluster-containing polyoxometalates, formulated as Na22{(SbW9O33)4[La3W6MO18(H2O)8(CH3COO)4]2}·nH2O (abbreviated as La6M2, M = Co/Mn) were synthesized and structurally characterized. Single-crystal X-ray diffraction analyses reveal that the polyanions of La6Co2 and La6Mn2 consist of the uncommon 3d-4f-5d clusters {La6W12Co2} and {La6W12Mn2}, which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds. Additionally, the polyanions can be extended into a two-dimensional (2D) frame by the linkage of peripheral Na+ ions. The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed, which is expected to exhibit a fascinating proton conductivity. The study of water-assisted proton conduction demonstrated that La6Co2 and La6Mn2 were temperature- and humidity-dependent proton conductors, respectively, and the proton conductivities could reach 1.3 × 10−2 and 2.3 × 10−2 S/cm at 65 ℃ and 90% RH conditions.
Fibrosis occurs due to the excessive deposition of extracellular matrix caused by cell injury. After various types of tissue injury, the dysregulation of the internal response can eventually lead to the destruction of organ structure and dysfunction. There is increasing evidence that oxidative stress, which is characterized by excessive production of hydrogen peroxide (H2O2), is an important cause of fibrosis. Therefore, we synthesized a biosensitive and efficient electrochemical H2O2 sensor based on PtNi nanoparticle-doped N-reduced graphene oxide (PtNi-N-rGO) to detect H2O2 released from transforming growth factor β1 (TGFβ1)-induced myofibroblast. In addition, the sensor could easily detect changes in H2O2 in the lung and bronchoalveolar lavage fluid (BALF) of mice with pulmonary fibrosis. Furthermore, the sensor could also detect H2O2 in activated hepatic stellate cells and the liver of carbon tetrachloride (CCl4)-induced liver fibrosis. Moreover, the alterations in H2O2 detected by the sensor were consistent with nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) protein expression and the staining results of pathological sections. Taken together, these results highlight the use of H2O2 sensors for the rapid detection of fibrosis and facilitate the rapid evaluation of antifibrotic drug candidates.
Oral squamous cell carcinoma (OSCC) is known as one of the most malignant tumors with high recurrence and fatality rate. The poor tumor-targeting ability of traditional chemotherapeutic drugs has been a grand challenge for anti-OSCC therapy. Beyond that, a large quantity of tumor associated macrophages in OSCC tissues further diminish the anti-tumor effects of these drugs. Therefore, we produced a therapeutic nano drug delivery system (FA-PEG-PLA-JQ1) through encapsulating JQ1 [a small-molecule inhibitor of bromodomain containing protein 4 (BRD4)] into the folic acid (FA)-modified nanoparticle (PEG-PLA), which could prolong the half-life of JQ1 and target the tumor tissues. And then, JQ1 released from this nanoparticle could prevent OSCC growth inducing tumor cell apoptosis, inhibiting tumor angiogenesis and the polarization of M2 type macrophages. In conclusion, our date demonstrated the therapeutic benefits of FA-PEG-PLA-JQ1 against OSCC in vivo or in vitro, which could be a novel treatment strategy for OSCC in coming days.
An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles. The key pre-aromatic spirocyclic intermediate initialized by the single electron transfer (SET) process of Togni's reagent Ⅱ promoted by the tertiary phosphine resulted in an intriguing and alternative tactic for the cleavage of C‒C bonds. By using inexpensive tertiary phosphine as the catalyst, this skeleton-reorganizing approach of N-containing heteroaryl ketones allows a streamlined assembly of complex N-fused heterocycles with broad functional group tolerance.
The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts. Herein, we report construction and transformation of three Pd(Ⅱ)-based metal-organic cages (MOCs) depending on different anions. Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36 are induced by BF4‒ or NO3‒, respectively. MOC-36 is kinetically favored and can undergo quantitative conversion to the thermodynamically preferred MOC-35 upon heating, accelerated by excess BF4‒ to motivate dissociative dynamics of Pd-vertices and lower activation barrier of cage transformation. The guest encapsulation behaviors of MOC-35 and MOC-36 have also been tested. These results manifest a significance of host-anion dynamics beyond complementary anion template, shedding light on the understanding of intricate anion recognition in nature.
Flexible aqueous zinc-ion batteries (AZIBs) with air-recharging capability are a promising self-powered system applied in future wearable electronics. It is desired to develop high-capacity air-rechargeable AZIBs. Herein, we developed a flexible AZIB with air-recharging capability based on trinitrohexaazatrinaphthylene (TNHATN) cathode and a ZnSO4 electrolyte. The flexible Zn//TNHATN battery exhibits high volumetric energy density (21.36 mWh/cm3) and excellent mechanical flexibility. Impressing, the discharged flexible Zn//TNHATN battery can be chemical self-charged via the redox reaction between TNHATN cathode and O2 from the air. After oxidation in air for 15 h, such flexible Zn//TNHATN battery can deliver a high specific capacity of 320 mAh/g at 0.5 A/g, displaying excellent air-recharging capability. Notably, this flexible Zn//TNHATN battery also works well in chemical or/and galvanostatic charging mixed modes, showing reusability. This work provides a new insight for designing flexible aqueous self-powered systems.
A new, four component copper(Ⅰ)-catalyzed interrupted click/radical relay cascade has been developed. This unprecedented interrupted click reaction provides a rapid modular synthesis of triazole sulfones, important privileged heterocyclic pharmacophores which cannot be accessed by a traditional click reaction. Radical interception of cuprate-triazole, the key reaction intermediate formed in situ, is an important feature of this process.
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