Latest ArticlesTwo 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.
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.
The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization. In this work, Au nanowires (Au-NW) modified with polyethyleneimine (PEI) molecule (Au-NW@PEI) is obtained by an up-bottom post-modification approach. Physical characterization, molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N interaction. Electrochemical experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction (GEOR) due to the electronic effect. Meanwhile, the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates possible. Therefore, the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%. The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures, which may have wide application in biomass development.
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.
A nine cyclic peptide (TCP-1) showed excellent specificity for colon cancer. TCP-1 binds with human tumor tissues at early stages and mice tumor with diameters of 1-4 mm, suggesting that TCP-1 may be used for early diagnosis of colon cancer. The mechanism of the targeted binding of TCP-1 to colon cancer was also studied using immunoprecipitation, LC-MS and bioinformatics. After screening and identifying of the possible binding target proteins of TCP-1, keratin, type Ⅱ cytoskeletal 5 was speculated to be the specific binding target protein of TCP-1 in human tumor tissue. Pharmacokinetics studies were conducted to investigate the target-mediated drug disposition of the new tumor-specific peptide by LC-MS/MS. The tissue distribution study showed that TCP-1 was found only in colon tumors (the target site) in tumor mice did not bind to any other tissues. Conjugating TCP-1 to tumor markedly increased its removal rate from blood circulation but mildly extended its staying time in vivo. In tumor mice, a lower AUC of TCP-1 (reduced by almost 35%) and 2-fold higher clearance were found compared to that of normal mice. The proposed metabolic pathway of TCP-1 in the kidney was also determined using LC-MSn-IT-TOF. The high specificity and low toxicity of the peptide may be caused by its extremely tight binding to the targets. Potential applications for future clinical use, including MRI and PET/CT were also explored, and this research may promote the development of colon cancer diagnostic technology research and provide new ideas and technical routes for tumor diagnostic technology.
Lead-free double perovskite nanocrystals (NCs) have emerged as a promising candidate in the optical field, owing to their non-toxic, good moist heat and chemical stability. However, their poor optical properties limited their application. To improve the optical properties of lead-free double perovskite NCs, metal ion doping or alloying had been suggested as a promising strategy. Here, we prepared monodisperse, uniformly sized, cubic morphology of Cs2AgBiCl6 NCs with different Na+ incorporation amounts via a simple hot-injection method. The Na+ incorporation broke the parity-forbidden transition by reducing the inversion symmetry of the electron wave function at the Ag site, which changed the parity of the self-trapped exciton wave function and thus allowed radiative recombination. As a result, the photoluminescence quantum yield (PLQY) of Na+-alloyed Cs2AgBiCl6 NCs (12.1%) was higher than that of Cs2AgBiCl6 NCs (2.4%), and the exciton lifetime of Na+-alloyed Cs2AgBiCl6 NCs increased to 36.98 ns from 17.58 ns for Cs2AgBiCl6 NCs. By adjusting the amount of Na+ incorporation, the band gap of Cs2AgBiCl6 NCs can be significantly tuned from ~2.90 eV to ~3.50 eV. Furthermore, the temperature-dependent photoluminescence spectra indicated that the Na+-alloyed Cs2AgBiCl6 NCs possessed higher longitudinal optical phonon energy and exciton binding energy compared to Cs2AgBiCl6 NCs. This suggested that there were strong exciton-phonon interactions during exciton recombination, a reduced probability of non-radiative processes, and excellent thermal stability. It offers a promising strategy for improving the optical properties of lead-free double perovskite NCs, and have the potential to replace traditional lead halide perovskite NCs in future optoelectronic applications.
Inhibition of mycobacterial membrane protein large 3 (MmpL3) thereby affecting the mycolic acid biosynthetic pathway has been proven to be an effective strategy for developing antitubercular drugs. Based on the X-ray crystal structure of MmpL3 inhibitor complexes, a series of novel 1,2,4-triazole derivatives were designed, synthesized and evaluated antitubercular activity against Mtb strain H37Rv. Comprehensive structure–activity relationship exploration resulted in the identification of compounds 21 and 28, which possess potent antitubercular activity against Mtb strain H37Rv [minimum inhibitory concentration (MIC) = 0.03–0.13 µg/mL] and the clinical isolates of multidrug resistance (MDR) and extensive drug resistance (XDR) tuberculosis (MIC = 0.06–1.0 µg/mL). Moreover, compounds 21 and 28 showed neglectable cytotoxicity (IC50 ≥ 32 µg/mL) to the mammalian Vero cells and favorable physicochemical and pharmacokinetic properties according to the in silico absorption, distribution, metabolism and excretion (ADME) prediction. Finally, the potential target of representative 1,2,4-triazole 28 was identified to be MmpL3 using a microscale thermophoresis (MST) assay.
Poly(ethylene oxide) (PEO) polymer electrolytes (PEs) have been commercially applied in LiFePO4||Li solid-state lithium batteries (SSLBs). However, it remains challenging to develop PEO-based PEs applicable to the high-voltage SSLBs with higher energy density, owing to the poor electrochemical stability of PEO. Herein, we report a scalable strategy for fabricating PEO-based PEs with high-voltage compatibility, by exploiting a new mechanism to stabilize the cathode-electrolyte interface in the high-voltage SSLBs. The protocol only involves a one-pot synthesis procedure to covalently crosslink the PEO chains, in the presence of high-content lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) salts and N,N-dimethylformamide (DMF). LiTFSI-DMF supramolecular aggregates are formed and firmly embedded in the polymer network, endowing the PE with high room-temperature ionic conductivity. The dissociated and highly concentrated TFSI− anions can enter the Helmholtz layer close to the high-voltage cathode, leading to the formation of a thin and homogeneous cathode electrolyte interface (CEI), mainly composed of LiF, on the cathode. The CEI with high electrochemical stability can effectively stabilize the cathode-electrolyte interface, enabling long-term stable cycling of the high-voltage LiCoO2||Li and nickel-rich NCM622||Li batteries at room temperature. The simplicity and scalability of the strategy makes the reported PEO-based PE potentially applicable in high-voltage SSLBs in practice.
Highly efficient catalysts for electrolysis of water are crucial to the development of hydrogen energy which is helpful to carbon neutralization. Recently, high temperature shock (HTS), with advantage of rapid speed, universality and scalable production, has been a promising method in synthesis of nanomaterials. In this paper, HST was used to treat low Pt loading Mo6S8 for enhanced water splitting performance. Impressively, the optimized MoS2/MoO2/Mo6S8 nano-composite with low Pt mass loading (~4%) displays well hydrogen evolution reaction (HER) electrochemical performance. The overpotential is 124 mV to reach 10 mA/cm2 and the corresponding Tafel slope is 88 mV/dec in acidic electrolyte. Its mass activity is 6.2 mA/µgPt at -124 mV vs. RHE, which is almost 2 times relative to 20% Pt/C. Moreover, it presents distinguished stability even after 2000 cycles. This work will broaden the way of catalysts preparation and the application of hydrogen evolution.
Second near-infrared (NIR-Ⅱ) light triggered in-situ tumor vaccination (ISTV) represents one of the most promising strategies in boosting the whole-body antitumor immunity. While most of previously developed nano-adjuvants for NIR-Ⅱ-triggered ISTV are “all-in-one” formulations, which may indiscriminately damage both the tumor cells and the immune cells, limiting the overall effect of immune response. To overcome this obstacle, we designed a “cocktail” nano-adjuvant by physically mixing hyaluronidases (HAase)-decorated gold nanostars (HA) for NIR-Ⅱ light triggered in situ production of tumor-associated antigens and CpG functionalized gold nanospheres (CA) for immune cells activation. Compared to “all-in-one” formulation, the “cocktail” nano-adjuvants displayed a significantly stronger immune response on NIR-Ⅱ light induced dendritic cells (DCs) mutation and T cells differentiation, greater effect on tumor-growth inhibition, and higher efficacy in inhibition of pulmonary metastases. What is more, increasing the molar ratio of HA to CA led to an enhanced anticancer immune responses. This study highlight the nano-adjuvant formulation effects on the treatment of tumors with multiple targets.