Latest ArticlesCarbon dots (CDs) with precise targeting function show great potential in the field of drug delivery therapeutics. In this study, the functionalized nucleus-targeting orange-emissive CDs with nuclear localization sequence (NLS) were loaded with adriamycin (DOX) to obtain a nucleus-targeting orange-emissive CDs drug delivery system (CDs-NLS-DOX), which delivered DOX to tumor cell nuclei to enhance its anti-tumor activity. The drug carrier orange-emissive CDs showed excitation-independent behavior, stable and enhanced imaging capability and good biocompatibility in vitro and in vivo. Meanwhile, the CDs-NLS could target the nuclei efficiently, and the CDs-NLS-DOX complexes had a high drug loading rate (59.4%) after loading DOX, exhibiting pH-dependent DOX release behavior through breaking acylhydrazone bond in a weak acidic environment. In addition, the CDs-NLS-DOX complexes exhibited an enhanced killing activity against human hepatoma cells (HepG2). The in vivo therapeutic effects on HepG2 nude mice transplanted tumors indicated the CDs-NLS-DOX had a stronger ability to inhibit tumor growth compared to free DOX. In short, CDs-NLS-DOX is expected to be a precise and efficient nucleus-targeting nano-drug delivery system for tumor treatment.
Detection and observation of reactive intermediates is an essential step in investigation of reaction pathways. However, most reactive intermediates are unstable and present at low concentrations; their short lifetimes make them difficult to detect and characterize. Supramolecular containers offer opportunities for the stabilization and characterization of those labile species, through isolation from the media and protection inside the cavity of the host. In this review, we summarize the examples of labile reaction intermediates that are stabilized and characterized with the help of supramolecular containers. The container compounds include carcerands, deep cavitands and amide naphthotubes. We focus on unstable guest species – cyclobutadiene, benzocyclopropenone, o-benzyne, 1,2,4,6-cycloheptatetraene, anti-Bredt's olefin, fluorophenoxycarbene, O-acylisoamide, and hemiaminal – that act as intermediates in certain organic reactions
Development of hydrothermally stable, low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge. We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO2/Al2O3 and ZSM-5. This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N2O formation than the corresponding metal oxide catalyst. Comparing with a Cu-CHA catalyst, the composite catalyst has a faster response to NH3 injection and less NH3 slip. Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn3+ species as a result of oxide-zeolite interaction, and this interaction leads to the generation of more NH4+ species bound to the Brønsted acid sites and more reactive NOx species absorbed on the Mn sites. Herein, we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N2 selectivity for NH3-SCR reaction. Practically, this work may provide an alternative methodology for low-temperature NOx control from diesel vehicles.
To promote the practices of perovskite photovoltaics, it requires to develop efficient perovskite solar cells (PVSCs) standing long-time operation under the adverse environments. Herein, we demonstrate that the tailor-made conjugated polymers as conductive adhesives stabilized the originally redox-reactive heterointerface between perovskite and metal oxide, facilitating the access of efficient and stable inverted PVSCs. It was revealed that bithiophene and phenyl alternating conjugated polymers with partial glycol chains atop of the metal oxide layer has resulted in effective organic-inorganic hybrid hole transporting bilayers, which allow maintaining efficient hole extraction and transport, meanwhile preventing halide migration to directly contact with the nickel oxide (NiOx) layer. As a result, the corresponding inverted PVSCs with the organic-inorganic hole transporting bilayers have achieved an excellent power conversion efficiency of 23.22%, outperforming 20.65% of bare NiOx-based devices. Moreover, the encapsulated PVSCs with organic-inorganic bilayers exhibited the excellent photostability with 91% of the initial efficiency after 1000-h one-sun equivalent illumination in ambient conditions. Overall, this work provides new insights into stabilizing the vulnerable heterointerface for perovskite solar cells.
Electrochemical sensing provides a powerful technological means for the therapeutic drug monitoring of drug-resistant tuberculosis but requires a functionalized electrode to capture the analytes and catalyze their redox reactions. Herein, we construct a nickel–tannic acid supramolecular network (Ni–TA) on the surface of electrospun-derived C–CeO2 nanofiber for the sensitive and simultaneous detection of isoniazid (INZ) and hydrazine (HYD). Mechanistic investigations demonstrate that Ni–TA is electronegative and hydrophilic, thus facilitating an efficient mass and electron transfer. Ni–TA/C–CeO2 has higher adsorption rate constants (0.091 g mg–1 h–1 for INZ, and 0.062 g mg–1 h–1 for HYD) than native C–CeO2 (0.075 g mg–1 h–1 for INZ, and 0.047 g mg–1 h–1 for HYD). Moreover, Ni–TA/C–CeO2 (56 Ω) has lower charge transfer resistances than C–CeO2 (417 Ω). Ni–TA/C–CeO2 performs low detection limits and wide linearity ranges for INZ (0.012 µmol/L and 0.1–400 µmol/L, respectively) and HYD (0.008 µmol/L and 0.015–1420 µmol/L, respectively), coupled with high selectivity, cycle stability and reproducibility. This research demonstrated the promising applications of Ni–TA/C–CeO2 by analyzing human-collected plasma and urine samples.
The practical application of high-energy-density lithium-sulfur (Li-S) batteries have been highly praised for energy storage devices, while are largely hindered by the "shuttling effect". Herein, core-shell carbon spheres composed of interlinked porous core and lamellar shell were designed to restrain the polysulfide shuttling. The microporous structure with pore size of around 1 nm effectively trap lithium polysulfides. Furthermore, the interconnected porous core shortens the ion transfer distance and the lamellar carbon shell endows the carbon spheres with fast electron conduction, finally facilitating polysulfide conversion kinetics. Therefore, the Li-S batteries with the carbon spheres as the interlayer show high discharge specific capacity of 1002 mAh/g at 2 C with 574 mAh/g remaining after 600 cycles, and high areal capacity of 5.48 mAh/cm2 with sulfur loading of 4.67 mg/cm2 at 0.1 C. The corresponding pouch cells also exhibit stable cycling stability with an initial discharge specific capacity of 1082 mAh/g at 0.1 C.
A photoinduced copper-catalyzed alkoxyl triggered C−C bond cleavage/aminocarbonylation cascade is presented. Through adjusting the structure of alkoxyl radical precursors, functionalized lactones and keto-amides were synthesized with good yields and excellent functional group tolerance under redox-neutral conditions. Notably, this protocol enables the integration of lactone fragments with many amine drugs and drug fragments.
An amphiphilic derivative with a large Stokes shift by introducing flexible hydrophilic long chains into a rigid ethylene-pyrene compound have been successfully synthesized. The alkylated compound exhibited a notable change in charge distribution, facilitating cation-π interactions. Through the process of amphiphilic self-assembly, the formation of highly ordered aggregates enabled effective photo-dimerization under 449 nm LED irradiation. Notably, this photo-responsive technology not only exhibited advanced multi-color emission effects, including white light emission but also exhibited environmentally friendly behavior in the aqueous phase.
The efficient conversion of CO2 into hydrocarbon fuels (CH4) with high selectivity is considered as a great challenge in photocatalysis owing to the multiple-electron transfer pathway and competitive H2 generation. Herein, we developed carbon dots (CDs)-modulated S-scheme heterojunction of CDs/NiAl-LDH@In2O3 (C-DH@IN) through a facile in-situ hydrothermal method. Thanks to the multi-shell nanotube structure, the C-DH@IN shows an enhanced CH4 evolution rate of 10.67 µmol h−1 g−1 and higher selectivity of CH4 (85.70%) compared with In2O3 and NiAl-LDH@In2O3 binary catalyst in the pure water without sacrificial agent. Electron spin resonance (ESR) and in situ Fourier transform infrared spectra verify that the constructed S-scheme heterojunction can possess the strong redox capability and the HCOO− and CH3O− as critical intermediates play an important role in selective CO2 reduction to generate CH4. Furthermore, CDs with superior photoabsorption can boost the electron transfer and absorb H+, thus improving the integration of H+ and CO2 molecule. Therefore, this work emphasizes a facile strategy to achieve efficient CO2-to-CH4 conversion based on construction of CDs-based heterojunction catalysts.
Cr(Ⅵ), one of the most hazardous metal pollutants, poses significant threats to the environment and human health. Herein, a novel MoS2 composite (MoS2/PVP/PAM) modified by polyvinylpyrrolidone (PVP) and polyacrylamide (PAM) was synthesized to enhance the removal of Cr(Ⅵ). Characterization analysis including SEM, XRD, FTIR, and XPS indicated that PVP and PAM could increase the interlayer spacing and the dispersibility of MoS2, and introduce pyrrolic N and amino functional groups. The batch experiments showed that MoS2/PVP/PAM represented excellent Cr(Ⅵ) removal performance over a wide pH range, and exhibited a significantly higher maximum Cr(Ⅵ) adsorption capacity (274.73mg/g, at pH 3.0, and 298K) than pure MoS2. The adsorption of Cr(Ⅵ) followed Langmuir and pseudo-second-order kinetic model, which was a homogeneous monolayer chemisorption process. MoS2/PVP/PAM showed stable removal of Cr(Ⅵ) in the presence of humic acid (HA), interfering cations and anions at different concentrations. Moreover, it had excellent selectivity for Cr(Ⅵ) (Kd value of 1.69× 107mL/g) when coexisting with a variety of competing ions. Multiple characterization revealed that Cr(Ⅵ) was reduced to low toxicity Cr(Ⅲ) by Mo4+ and S2−, and then chelated on the surface of the adsorbent by pyrrolic N. This research expanded the design concept for MoS2 composites by demonstrating the potential of MoS2/PVP/PAM as a promising material for selective elimination of Cr(Ⅵ) in water.
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