Latest ArticlesRadiation damage can cause a series of gastrointestinal (GI) tract diseases. The development of safe and effective GI tract radioprotectants still remains a great challenge clinically. Here, we firstly report an oral radioprotectant Gel@GYY that integrates a porous gelatin-based (Gel) hydrogel and a pH-responsive hydrogen sulfide (H2S) donor GYY4137 (morpholin-4-ium 4 methoxyphenyl(morpholino) phosphinodithioate). Gel@GYY has a remarkable adhesion ability and long retention time, which not only enables responsive release of low-dose H2S in stomach and subsequently sustained release of H2S in the whole intestinal tract especially in the colon, but also ensures a close contact between H2S and GI tract. The released H2S can effectively scavenge free radicals induced by X-ray radiation, reduce lipid peroxidation level, repair DNA damage and recover vital superoxide dismutase and glutathione peroxidase activities. Meanwhile, the released H2S inhibits radiation-induced activation of nuclear factor κB (NF-κB), thus reducing inflammatory cytokines levels in GI tract. After treatment, Gel@GYY displays efficient excretion from mice body due to its biodegradability. This work provides a new insight for therapeutic application of intelligent H2S-releasing oral delivery system and potential alternative to clinical GI physical damage protectant.
Metastable molybdenum carbide (α-MoC), as a catalyst and an excellent support for metal catalysts, has been widely used in thermo/electro-catalytic reactions. However, the selective synthesis of α-MoC remains a great challenge. Herein, a simple one-pot synthetic strategy for the selective preparation of metastable α-MoC is proposed by electrochemical co-reduction of CO2 and MoO3 in a low-temperature eutectic molten carbonate. The synthesized α-MoC shows a reed flower-like morphology. By controlling the electrolysis time and monitoring the phase and morphology of the obtained products, the growth process of α-MoC is revealed, where the carbon matrix is deposited first followed by the growth of α-MoC from the carbon matrix. Moreover, by analyzing the composition of the electrolytic products, the formation mechanism for α-MoC is proposed. In addition, through this one-pot synthetic strategy, S-doped α-MoC is successfully synthesized. Density functional theory (DFT) calculations reveal that S doping enhanced the HER performance of α-MoC by facilitating water absorption and dissociation and weakening the bond energy of Mo-H to accelerate H desorption. The present work not only highlights the valuable utilization of CO2 but also offers a new perspective on the design and controllable synthesis of metal carbides and their derivatives.
Photocatalytic and photoinduced silyl radicals cascade cyclization procedures for the green and simple preparation of fused tetracyclic skeleton silylated indolo[2,1-a]isoquinoline-6(5H)-ones from 2-aryl-N-acryloyl indoles with hydrosilanes are developed. The photocatalytic reaction is carried out with 9,10-dicyanoanthracene (DCA) as an organophotocatalyst and 3-acetoxyquinuclidine as hydrogen atom transfer (HAT) catalyst at room temperature under metal- and oxidant-free conditions. The keys to the success of photoredox-catalytic conversion include (1) the reductive quenching of DCA* [E1/2(*P/P–) = +1.97 V vs. SCE in MeCN] by 3-acetoxyquinuclidine (Ep = +1.22 V vs. SCE in MeCN), and (2) the thermodynamic feasibility of hydrogen atom abstraction from hydridic Si–H bond by electrophilic N+•. Particularly, the simple photoinduced cascade cyclization using (TMS)3SiH with 2-aryl-N-acryloyl indoles was exploited via an electron−donor−acceptor (EDA) complex under visible light irradiation.
Atomization energy (AE) is an important indicator for measuring material stability and reactivity, which refers to the energy change when a polyatomic molecule decomposes into its constituent atoms. Predicting AE based on the structural information of molecules has been a focus of researchers, but existing methods have limitations such as being time-consuming or requiring complex preprocessing and large amounts of training data. Deep learning (DL), a new branch of machine learning (ML), has shown promise in learning internal rules and hierarchical representations of sample data, making it a potential solution for AE prediction. To address this problem, we propose a natural-parameter network (NPN) approach for AE prediction. This method establishes a clearer statistical interpretation of the relationship between the network's output and the given data. We use the Coulomb matrix (CM) method to represent each compound as a structural information matrix. Furthermore, we also designed an end-to-end predictive model. Experimental results demonstrate that our method achieves excellent performance on the QM7 and BC2P datasets, and the mean absolute error (MAE) obtained on the QM7 test set ranges from 0.2 kcal/mol to 3 kcal/mol. The optimal result of our method is approximately an order of magnitude higher than the accuracy of 3 kcal/mol in published works. Additionally, our approach significantly accelerates the prediction time. Overall, this study presents a promising approach to accelerate the process of predicting structures using DL, and provides a valuable contribution to the field of chemical energy prediction.
Carbon dots (CDs) have been attracted much attention and widely studied due to their excellent fluorescence (FL) properties, better biocompatibility and outstanding photo/chemical stability. However, the disadvantage of lower quantum yield (QY) still limits its wide application. Herein, we reported a novel and convenient strategy to prepare photo-induced Ag/CDs (p-Ag/CDs) by irradiating the mixed Ag+ and hydrophobic CDs (h-CDs) acetone solution with ultraviolet (UV) light. The obtained p-Ag/CDs exhibit a greatly enhanced FL emission together with a blue shift (460 nm) than h-CDs (520 nm). The QY of p-Ag/CDs is measured to be 51.1%, which is 10.4 times higher than that of h-CDs (4.9%), indicating that photo-induced Ag modulation can effectively improve the optical properties of CDs. The mechanisms for the FL enhancement and blue shift of h-CDs are studied in detail. The results prove that the greatly enhanced FL emission is from the generated Ag nanoparticles (AgNPs) by UV light irradiation based on metal-enhanced fluorescence (MEF), and the increased oxygen-contained groups in this process lead to the blue shift in CDs fluorescence. Interestingly, the p-Ag/CDs exhibit higher sensitivity and selectivity for sulfide ions (S2−) detection than that of h-CDs, which have a lower response to S2−. This work not only offers a novel strategy to improve the FL properties of materials but also endows them with new functions and broadens their application fields.
Organic long-persistent luminescence (LPL) materials, featuring low preparation cost, eco-friendly synthesis, and easy modification of functional groups, have exhibited extensive applications in information encryption, anti-counterfeiting, and biological imaging. Several design strategies including crystallization-inducement, H-aggregation, and host–guest doping to enhance persistent-room-temperature phosphorescence (RTP) effect by precisely controlling intersystem crossing (ISC) constant and suppressing nonradiative decay rates, those are important strategies to enable LPL performance. Among the strategies, researchers have made several efforts to enhance persistent-RTP effect by host–guest interaction, in which the host matrices provide a rigid environment for phosphor guest molecules. The interaction of the luminescent guest molecules with the host matrix can effectively reduce the vibration and rotation of the luminescent molecules, and suppress the non-radiative inactivation, thereby improving the phosphorescence quantum yield. This review aims to summarize several design strategies of pure organic LPL materials based on persistent-RTP effect through host–guest interaction, and describe some applications of pure organic LPL materials in different fields.
Drug loading capacity is very important in the construction of targeted drug delivery systems (TDDSs) for the improvement of drug delivery efficiency. However, the drug-loading capacity of most nanomaterials is non-idealistic, and developing the high drug-loading TDDSs is still a critical challenge. In this work, an ultrahigh loading system (denoted as HMPB2) was prepared via J-aggregation of an aza-boron dipyrromethene derivative (Bod) by using hollow MnO2 modified with glucosamine pillar[5]arene as a carrier, which was demonstrated to have typical J-aggregate absorption of Bod, specific cancer cells targeting ability, negligible dark cytotoxicity, and potent phototoxicity. This work provides a successful example to construct an ultrahigh drug-loading system via J-aggregation for targeted delivery.
To achieve a lower detection limit has always been a goal of analytical chemists. Herein, we demonstrate the first picomolar level detection capability for Fe3+ ion via luminescence detection technology. The results of structural analysis and theoretical calculation show that Fe3+ ions are adsorbed on the central node of Eu-DBM (DBM = dibenzoylmethane) sensor in the form of single ion at ultralow concentration. Subsequently, the pathways of photo-induced charge and energy transfer of the obtained Eu-DBM@Fe3+ material have been changed, from the initial DBM-to-Eu3+ before Fe3+ adsorption to the ultimate DBM-to-Fe3+ after adsorption process, which quenches the luminescence of Eu3+ ion. This work not only obtains the highly sensitive luminescence detection ability, but also innovatively proposes the single-ion adsorption mechanism, both of which have important scientific and application values for the development of more efficient detection agents in the future.
Photocatalytic activation of peroxymonosulfate (PMS) has garnered a lot of interest in the field of wastewater treatment. Herein, a plasmonic Ag nanoparticles decorated MIL-101(Fe) hybrid was synthesized through a photodeposition process. Upon light irradiation, the Ag/MIL-101(Fe) exhibit reinforced photocatalytic activities for elimination of bisphenol A (BPA) with PMS. The optimized 2.0% Ag/MIL-101(Fe) composite presented the highest photocatalytic activity with kinetic constant k of 0.102 min−1, which was about 10-fold of the pristine MIL-101(Fe). Loading of plasmonic Ag into MIL-101(Fe) boosts photoinduced carrier separation and accelerates PMS activation to generate strong oxidative radicals. Photoelectrochemical tests and multiple spectroscopic studies confirmed the promoted charge carrier separation and transfer capability of Ag/MIL-101(Fe). Combining the results of radical trapping experiments and electron spin resonance (ESR), the formed SO4•−, •OH, •O2− and 1O2 had a significant role in the photocatalytic process. According to intermediate study, the degradation pathway was studied, and the possible mechanism was proposed.
Fluorescent silicon quantum dots (Si QDs) were hydrothermally synthesized from a mixture of 3(2-aminoethylamino) propyl (dimethoxymethylsilane) (AEAPDMMS) and poly(vinylpyrrolidine) (PVP). The resulting Si QDs exhibited good water solubility and high stability. Under the optimized conditions, the probe revealed an excellent linear fluorescence quenching effect on Co2+ ranging from 1 µmol/L to 120 µmol/L with a limit of detection of 0.37 µmol/L (based on 3 s/k). The quenching mechanism was studied, showing that static quenching (SQE) causes the main effect. Furthermore, the test paper based on Si QDs was prepared, which is cost-effective, high sensitivity, good selectivity, easy to use and show excellent anti-interference capability. This method was applied to analyze the content of Co2+ in environmental water samples with satisfying results.
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