Latest ArticlesMetal-organic frameworks (MOFs) functionalized with open metal sites (OMSs) have received widespread attention in various applications due to their fascinating electronic properties and unique interactions with guest molecules. However, rational tailoring of the coordination environment of metal nodes during the synthesis of MOFs remains a great challenge due to their tendency of saturated coordination with linkers. Herein, we reported the construction of three new MOFs featuring unsaturated Cu(Ⅱ) sites, namely [Cu(HCOO)(pzta)]n (HL-1), {[Cu(PTA)0.5(pzta)(H2O)]·2H2O}n (HL-2) and [Cu(NA)0.5(pzta)]n (HL-3) (Hpzta = 3-pyrazinyl-1,2,4-triazole; PTA = terephthalic acid; NA = 1,4-naphthalene dicarboxylic acid), based on the mixed-linker strategy via specific selection of versatile Hpzta ligand and carboxylate ligands. Remarkably, the obtained MOFs exhibited excellent activity and good recyclability for the catalytic reduction of nitroaromatics under mild conditions (25 ℃ and 1 atm). In particular, the complete conversion of 4-nitrophenol (4-NP) took only 30 s on HL-2, reaching a record-high TOF value compared with previously reported metal catalysts. The combined experimental and theoretical studies on HL-2 revealed that the open Cu site with positive-charged nature could improve the adsorption and subsequent electron transport between the substrates, and was responsible for the outstanding performance. This work shined lights on the further enhancement of performance for MOFs through rational OMSs construction.
Recently, the utilization of nonsteroidal anti-inflammatory drugs (NSAIDs) to sensitize cisplatin (CDDP) has gained substantial traction in the treatment of ovarian cancer (OC). However, even widely employed NSAIDs such as celecoxib and naproxen carry an elevated risk of cardiovascular events, notably thrombosis. Furthermore, the diminished sensitivity to CDDP therapy in OC is multifactorial, rendering the application of NSAIDs only partially effective due to their cyclooxygenase-2 (COX-2) inhibiting mechanism. Hence, in this study, reactive oxygen species (ROS)-responsive composite nano-hydrangeas loaded with the Chinese medicine small molecule allicin and platinum(Ⅳ) prodrug (DTP@AP NPs) were prepared to achieve comprehensive chemosensitization. On one front, allicin achieved COX-2 blocking therapy, encompassing the inhibition of proliferation, angiogenesis and endothelial mesenchymal transition (EMT), thereby mitigating the adverse impacts of CDDP chemotherapy. Simultaneously, synergistic chemosensitization was achieved from multifaceted mechanisms by decreasing CDDP inactivation, damaging mitochondria and inhibiting DNA repair. In essence, these findings provided an optimized approach for synergizing CDDP with COX-2 inhibitors, offering a promising avenue for enhancing OC treatment outcomes.
Electron-deficient viologens are widely used as ligands or structure-directing agents (SDAs) to synthesize crystalline X-ray induced photochromic materials. Here, a new rational strategy of anion-directed folding a flexible cation (H2imb)2+ ((H2imb)2+ = di-protonated 2,3-bis(imidazolin-2-yl)-2,3-dimethylbutane) has been developed. Electron-donating Cl− and (ZnCl4)2− are used to direct folding a flexible electron-deficient (H2imb)2+ cation. Three complexes (H2imb)(NO3)2 (1), (H2imb)Cl2·H2O (2), and (H2imb)ZnCl4 (3) have been synthesized in which (H2imb)2+ crystallize in an anti-conformation, 88.8°-gauche, and 51.8°-gauche, respectively. In contrary to X-ray silent complex 1, X-ray induced photochromism has been achieved in both complex 2 and 3. An intermolecular charge-transfer mechanism has been elucidated and the anion directed folding of (H2imb)2+ has been validated to be critical to yield colored long-lived charge-separated states.
Bioprinting is emerging as an advanced tool in tissue engineering. However, there is still a lack of bioinks able to form hydrogels with desirable bioactivities that support positive cell behaviors. In this study, modified plasma proteins capable of forming hydrogels with multiple biological functions are developed as bioinks for digital light processing (DLP) printing. The Plasma-MA (BM) was synthesized via a one-pot method through the reaction between the fresh frozen plasma and methacrylic anhydride. The methacrylated levels were observed to influence the physical properties of BM hydrogels including mechanical properties, swelling, and degradation. The photo-crosslinked BM hydrogels can sustainedly release vascular endothelial growth factor (VEGF) and exhibit positive biological effects on cell adhesion and proliferation, and cell functionality such as tube formation of human umbilical vein endothelial cells (HUVECs), and neurite elongation of rat pheochromocytoma cells (PC12). Meanwhile, BM hydrogels can also induce cell infiltration, modulate immune response, and promote angiogenesis in vivo. Moreover, the plasma bioinks can be used to fabricate customized scaffolds with complex structures through a DLP printing process. These findings implicate that the modified plasma with growth factor release is a promising candidate for bioprinting in autologous and personalized tissue engineering.
Traditional therapies such as surgery and endocrine therapy no longer meet the clinical needs in prostate cancer treatment, and more effective treatments are urgently required. Recent studies have reported that targeted inhibition of the transcription factor cyclin dependent kinase 7 (CDK7) could effectively suppress prostate cancer progression. However, the toxicity of CDK7 inhibitors such as THZ1 is the main limitation of the clinical application. In this work, we synthesized Cys8E (C8E) nanoparticles (NPs) loaded with THZ1 (C8E@THZ1), a novel GSH-targeting and stimuli-responsive nano-delivery platform, and investigated its anti-tumor potential and biosafety properties. In vitro, C8E@THZ1 potently inhibited the proliferation and promoted the apoptosis of prostate cancer cells. On tumor-bearing mice, C8E@THZ1 inhibited tumors by up to 85%, while the damage of THZ1 to liver function was effectively avoided. These results confirmed that inhibition of CDK7 can effectively block the progression of prostate cancer, and that Cys8E NPs is a highly prospective delivery platform to promote the clinical application of CDK7 inhibitors.
Urea is extensively used in agriculture and chemical industry, and it is produced on an industrial scale from CO2 and Haber–Bosch NH3 under relatively high temperature and high pressure conditions, which demands high energy input and generates masses of carbon footprint. The conversion of CO2 and N sources (such as NO2−, NO3−, and N2) through electrocatalytic reactions under ambient conditions is a promising alternative to realize efficient urea synthesis. Of note, the design of electrocatalyst is one of the key factors that can improve the efficiency and selectivity of C–N coupling reactions. Defect engineering is an intriguing strategy for regulating the electronic structure and charge density of electrocatalysts, which endows electrocatalysts with excellent physicochemical properties and optimized adsorption energy of the reaction intermediates to reduce the kinetic barriers. In this minireview, recent advances of defect engineered electrocatalysts in urea electrosynthesis from CO2 and various N reactants are firstly introduced. Mechanistic discussions of C–N coupling in these advances are presented, with the aim of directing future investigations on improving the urea yield. Finally, the prospects and challenges of defect engineered electrocatalysts for urea synthesis are discussed. This overview is expected to provide in-depth understanding of structure–reactivity relationship and shed light on future electrocatalytic C–N coupling reactions.
Under the guidance of the approach which integrates molecular networking, MolNetEnhancer and Network Annotation Propagation (NAP), daphnaltaicanoids A and B (1 and 2) with unprecedented 9-oxa-tetracyclo[6.6.1.02,6.08,13]pentadecane and tetracyclo[5.3.0.12,5.24,11]tridecane central frameworks were isolated from Daphne altaica Pall., representing two types of unparalleled meroterpenoid cores. Their structures were elucidated by extensive spectroscopic analysis, nuclear magnetic resonance (NMR) calculations, DP4+ analysis and electronic circular dichroism (ECD) calculations. The plausible biosynthetic pathways for 1 and 2 were postulated. Biologically, 2 exerted potent neuroprotective activities which were superior to trolox at 12.5 and 25 µmol/L. Moreover, 1 and 2 exhibited more noticeable acetylcholinesterase inhibitory activities than donepezil. Molecular docking simulations were performed to explore the intermolecular interaction of compounds 1 and 2 with acetylcholinesterase. The bioactivity evaluation results highlight the prospects of 1 and 2 as a novel category of neurological agents.
Safety and energy density are significant for lithium-ion batteries (LIBs), and the flammable organic electrolyte is one of the most critical causes of the safety problem of LIBs. Although LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode with high capacity can improve the energy density, the interface stability between NCM811 cathode and electrolytes needs to be improved. Herein, we report a multifunctional additive, diethyl(2-(triethoxysilyl)ethyl)phosphonate (DETSP), which can suppress the flammability of the electrolyte and enhance the cycling stability of NCM811 cathode with a capacity retention of 89.9% after 400 cycles at 1 C, while that of the blank electrolyte is merely 61.3%. In addition, DETSP is compatible well with the graphite anode without impairing the electrochemical performances. Significantly, the performance and safety of NCM811/graphite full cells are also improved. Experimental and theoretical results demonstrate that DETSP can scavenge acidic byproducts and is beneficial to form a stable cathode-electrolyte interface (CEI). Accordingly, DETSP can potentially be an effective solution to ameliorating the safety of the commercial electrolyte and improving the stability of high-voltage cathodes.
Searching for efficient nonprecious metal-based catalysts toward oxygen evolution reaction (OER) are of significance for seawater electrolysis. Herein, a core–shell-structured hybrid of cobalt phosphide nanowires@NiFe layered double hydroxide nanosheets grown on conductive nickel foam (CoP@NiFe LDH/NF) is prepared by a feasible approach at low temperature. The charming structure can provide numerous phosphide/hydroxide heterogenous interfaces, expose abundant active sites, and boost electron/mass transfer, synergistically enhancing catalytic OER activity. When employed as an electrocatalyst toward the OER, the resultant CoP@NiFe LDH/NF only requires a small overpotential of 287 mV to provide 300 mA/cm2 current density as well as long-time durability in 1.0 mol/L KOH seawater. The regulation of electronic states and surface reconstruction synergistically contribute to highly efficient seawater oxidation. This work provides an opportunity to construct efficient and inexpensive electrocatalysts for hydrogen production.
Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal lung disease characterized by pulmonary inflammation, oxidative stress, and excessive extracellular matrix (ECM) deposition. Current anti-fibrotic drugs for IPF treatment in the clinic lack selectivity and demonstrate unsatisfactory efficacy, highlighting the urgent necessity for a novel therapeutic strategy. Taraxasterol (TA), which has biological activities against lung injury induced by various factors, is a potential anti-IPF drug due to its anti-inflammatory, antioxidant and lung-protective effects. However, the protective effect of TA on IPF has not been confirmed, and its clinical application is limited due to its poor aqueous solubility. In this study, we demonstrated that TA could inhibit epithelial-mesenchymal transition (EMT) and migration of A549 cells by inhibiting the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. To improve the aqueous solubility and pulmonary administration performance of TA, we prepared TA loaded methoxy poly(ethylene glycol)-poly(d, l-lactide) (mPEG-PLA)/d-α-tocopheryl polyethylene glycol succinate (TPGS) mixed polymeric micelles (TA-PM). Then a MicroSprayerⓇ Aerosolizer was used to deliver TA-PM once every two days for three weeks to evaluate their therapeutic effects on bleomycin (BLM)-induced IPF mice. Our results demonstrated that inhaled TA-PM significantly inhibited BLM-induced inflammation, oxidative stress and fibrosis in lung tissue. Furthermore, TA-PM exhibited high pulmonary deposition and retention by pulmonary administration, along with a favorable safety profile. Overall, this study emphasizes the potential of inhaled TA-PM as a promising treatment for IPF, providing a new opportunity for their clinical application.