Latest ArticlesIncreasing use of silver in various fields has caused Ag+ pollution in water environment, taking great threats to people's health. As a consequence, establishing rapid and reliable methods for sensitive determination of Ag+ is of great significance. Fluorescent (FL) sensors based on carbon dots (CDs), an excellent carbonaceous nanomaterial with strong and stable fluorescence, have absorbed extensive attentions in analysis of pollutants due to its advantages of carbon sources being readily available, low cost, easy operation and fast response. Moreover, ion-imprinting is a better way to increase the selectivity of the proposed method. Present work described an effective method for the sensitive measurement of silver ion in water samples in combination with magnetic ion-imprinted solid phase extraction and CDs based fluorescent sensor, which took full advantages of easy separation and high enrichment of magnetic solid phase extraction, high selectivity of ion-imprinting technology, and sensitivity and rapid response of fluorescent sensor from CDs. Sulfur-doped CDs derived from dithizone and magnetic ion-imprinted nanomaterial were prepared, and characterized with Fourier transform infrared spectroscopy and transmission electron microscope, etc. Magnetic Ag+ imprinted nanomaterial based solid phase extraction was employed for separating and enriching Ag+ from water samples. The significant parameters were optimized in detail. Under the optimal conditions, the proposed method provided good linearity in the range of 0.01–0.4 µmol/L and low detection limit of 3 nmol/L. The reliability of the proposed method was validated with real water samples, and the results demonstrated that the proposed method was simple, robust, selective and sensitive detection tool for Ag+ in real water samples.
Ferroelastic hybrid perovskite materials have been revealed the significance in the applications of switches, sensors, actuators, etc. However, it remains a challenge to design high-temperature ferroelastic to meet the requirements for the practical applications. Herein, we reported an one-dimensional organic-inorganic hybrid perovskites (OIHP) (3-methylpyrazolium)CdCl3 (3-MBCC), which possesses a mmmF2/m ferroelastic phase transition at 263 K. Moreover, utilizing crystal engineering, we replace –CH3 with –NH2 and –H, which increases the intermolecular force between organic cations and inorganic frameworks. The phase transition temperature of (3-aminopyrazolium)CdCl3 (3-ABCC), and (pyrazolium)CdCl3 (BCC) increased by 73 K and 10 K, respectively. Particularly, BCC undergoes an unconventional inverse temperature symmetry breaking (ISTB) ferroelastic phase transition around 273 K. Differently, it transforms from a high symmetry low-temperature paraelastic phase (point group 2/m) to a low symmetry high-temperature ferroelastic phase (point group 1) originating from the rare mechanism of displacement of organic cations phase transition. It means that crystal BCC retains in ferroelastic phase above 273 K until melting point (446 K). Furthermore, characteristic ferroelastic domain patterns on crystal BCC are confirmed with polarized optical microscopy. Our study enriches the molecular mechanism of ferroelastics in the family of organic-inorganic hybrids and opens up a new avenue for exploring high-temperature ferroic materials.
The relationship mechanism between the material pore structures and cathodic iodine chemistry plays a vital role in efficient Zn-I2 batteries, but is unclear, retarding further advances. This work innovatively indicates a great contribution of ~2.5 nm pore structure of nanocarbons to efficient iodine adsorption, rapid I− ↔ I2 conversion, and polyiodide inhibition, via scrupulously designing catalysts with controllable pore sizes systematically. The I2-loading within the designed nitrogen-doped nanocarbons can reach up to as high as 60.8 wt%. The batteries based on the cathode deliver impressive performances with a large capacity of 178.8 mAh/g and long-term cycling stability more than 4000 h at 5.0 C. Notably, these is no polyiodide such as I3− and I5− detected during the charge-discharge processes from comprehensive electrochemical cyclic voltammetry, X-ray photoelectron spectroscopy, and Raman technique. This work provides a novel knowledge-guided concept for rational pore design, promising better Zn-I2 batteries, which is also hoped to benefit other advanced energy technologies, such as Li–S, Li-ion, and Al–I2 batteries.
In the face of multiple challenges brought by the changes of global climate and environment, developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon neutrality. Aqueous batteries have become a research hotspot due to their advantages of using the multivalent charge carrier, high ionic conductivity, environmental friendliness and cost effectiveness. In this work, the Cu2Se@C (Cu2Se coated on carbon clothes) thin film with a three-dimensional braided structure is fabricated by a simple electrochemical deposition method for Cu2+ storage for the first time. Compared with the commercial Cu2Se powder, the well-designed Cu2Se@C film shows enhanced specific capacity (640 mAh/g at 0.5 A/g) and rate performance (542 mAh/g at 5 A/g) as well as superior cycling stability (82.7% capacity retention after 1000 cycles at 1 A/g). The Cu2+ storage mechanism of the Cu2Se@C electrode is based on a reversible phase transition process of Cu2Se ↔ Cu2-xSe ↔ CuSe ↔ CuSe2. In kinetic characteristic analysis, the Cu2Se@C electrode demonstrates faster Cu2+ diffusion in discharge process than charge process resulting from the phase transition and the variation of interplanar spacing. This work highlights a facile one-piece design strategy and opens a new gateway for the exploration of advanced aqueous energy storage systems.
Nanoplastics (NPs) in aqueous environment have become a category of emerging pollutants on account of their potential risks to both human health and environment. The detection of NPs is a great challenge due to the lack of sensitive and selective sensing materials with fast response time and wide sensing range of particle sizes. Herein, a Tb-based coordination polymer has been synthesized for luminescent detection of nanopolystyrene with different particle sizes in aqueous solutions, showing a low limit of detection, fast response time within 10 s and high selectivity in the presence of other plastics. The “turn-on” sensing mechanism is studied in detail. This work provides a facile method for the fast detection of NPs.
Porphyrins and their derivatives are excellent photosensitizers in photodynamic therapy (PDT). The modification of porphyrin molecules into metal-organic cages (MOCs) is a viable strategy to improve their bioavailability. In this work, MOC C66 based on porphyrin was synthesised by a one-pot self-assembly method. The three-dimensional structure of the metal-organic cage ameliorated the aggregation and self-quenching of porphyrins and increased the molar absorption coefficient in the visible light region, which enhanced the reactive oxygen species (ROS) yield of porphyrins and effectively improved the efficiency of photodynamic therapy. ROS generation ability tests in solution confirmed the improved reactive oxygen capacity of the cage, which showed greater phototoxicity to HeLa and MCF-7 cells in vitro, suggesting a new strategy for future modifications of the simple synthesis of porphyrins as photosensitizers.
Multifunctional drug delivery systems (DDSs) have shown great prospects in overcoming the heterogeneous barrier of delivery drugs to the complex tumor microenvironment (TME). In this study, multifunctional AS/Ge-pNAB microgels with dual-active targeting, triple environment responsiveness, and fluorescence imaging capability were prepared through a straightforward procedure. This was aimed to improve the antitumor therapeutic application of gambogic acid (GA) based on the biological characteristics of TME. The microgels have a uniform double-layer structure with aptamer in the outer layer which helps in recognizing receptors on the tumor cells. The GA loaded nano-herb exhibited environment-responsive drug release profiles under acidic pH, reductant and high temperature. The nano-herb significantly improved the accumulation of GA in tumor sites through the synergistic combination of the enhanced permeability and retention effect and dual-ligand mediated internalization. Then, it accelerated intracellular drug release and killed tumor cells. Therefore, the nano-herb had specific therapeutic effects on the tumor in vitro and in vivo as they remarkably inhibited tumor growth while depicting optimal biosafety and lower levels of off-target toxicity. Overall, these findings demonstrate the great potential of the multifunctional AS/Ge-pNAB microgels for precisely targeted GA delivery and open a new avenue for the facile preparation of multifunctional DDSs.
Dendritic cell (DC)-targeted delivery of mRNA is a prominent method to boost the efficacy of mRNA tumor vaccines. The targeting ligands are often modified on nanocarriers by polyethylene glycol (PEG) linker in mRNA delivery systems. Whether the PEG linker length influences the targeting delivery efficiency of mRNA nanocarrier in vivo remains unclear. Here, we designed and constructed DC-targeted mRNA delivery systems modified by mannose via different PEG linker lengths (100/400/1000/2000) (MPn-LPX). The top candidate MP400-LPX (the linker was PEG400) showed the optimal mRNA expression and antigen presentation owing to the highly efficient uptake by DCs. Furthermore, MP400-LPX could better inhibited tumor growth and extended survival in the E.G7-OVA lymphoma and TC-1 cervical tumor mouse model. Collectively, these results demonstrated that PEG400 was the optimal linker for the PEGylated DC-targeted mRNA vaccines. Our findings provided a new platform for the rational design of targeted mRNA nanovaccines with shorter-length PEG.
The interaction among type Ⅱ collagen (CII), human DR4 major histocompatibility complex type Ⅱ molecule (MHC Ⅱ) and T-cell receptor (TCR) is associated with the development of rheumatoid arthritis (RA). The activation of T cells can be reduced through exposure to modified CII(263–272) glycopeptide fragment via competitive inhibition with self-antigen. In this work, 30 peptides based on the sequence of CII(263–272) were prepared and evaluated for their binding to DR4 protein by surface plasmon resonance (SPR) assay. The effect on the secretion of pro-inflammatory factors by the spleen cells in collagen induced rheumatoid arthritis (CIA) mouse was also investigated. Two N-glycosylated CII peptides were identified to have strong binding to the human recombinant DR4 protein and weak proinflammatory effect. These glycopeptides could be developed as therapeutic saccharide vaccines for the treatment of rheumatoid arthritis (RA).
High-performance carbon dots (CDs) allowing the application in high-end display devices are highly desirable and usually limited by the absence of simple and easy synthesis methods. In this work, we exploited an easy-to-implement strategy for the one-step synthesis of green-emitting CDs (G-CDs) with superb optical properties. The G-CDs were synthesized using m-phenylenediamine (m-PD) as a single precursor, and the reaction reacted at 180 ℃ for 12 h The resultant G-CDs exhibit high-purity and excitation-independent green fluorescence with the photoluminescence (PL) peak located at 516 nm, full width at half maximum (FWHM) of 46 nm, and PL quantum yield (QY) of ~80% under the 470 nm excitation light. The G-CDs and corresponding composite film prepared with polyvinyl butyral (G-CDs@PVB) exhibit good PL stability after undergoing long-time storage for one year and 360 h exposure under 460 nm blue light. The G-CDs@PVB film was used as color-conversion materials in green-emitting light-emitting diode (LED) application, exhibiting a Commission internationale de l'Eclairage (CIE) chromaticity coordinate of (0.21, 0.44). The film was also used in CD-based liquid crystal display (CD-LCD) application, achieving a color gamut value of 85%. This work will offer a working basis for the synthesis of high-performance CDs as well as their application in displays.
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