Latest ArticlesThe bioactive constituents found in natural products (NPs) are crucial in protein-ligand interactions and drug discovery. However, it is difficult to identify ligand molecules from complex NPs that specifically bind to target protein, which often requires time-consuming and labor-intensive processes such as isolation and enrichment. To address this issue, in this study we developed a method that combines ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS) with molecular dynamics (MD) simulation to identify and observe, rapidly and efficiently, the bioactive components in NPs that bind to specific protein target. In this method, a specific protein target was introduced online using a three-way valve to form a protein-ligand complex. The complex was then detected in real time using high-resolution MS to identify potential ligands. Based on our method, only 10 molecules from green tea (a representative natural product), including the commonly reported epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), as well as the previously unreported eepicatechin (4β→8)-epigallocatechin 3-O-gallate (EC-EGCG) and eepiafzelechin 3-O-gallate-(4β→8)-epigallocatechin 3-O-gallate (EFG-EGCG), were screened out, which could form complexes with Aβ1–42 (a representative protein target), and could be potential ligands of Aβ1–42. Among of them, EC-EGCG demonstrated the highest binding free energy with Aβ1–42 (−68.54 ± 3.82 kcal/mol). On the other side, even though the caffeine had the highest signal among green tea extracts, it was not observed to form a complex with Aβ1–42. Compared to other methods such as affinity selection mass spectrometry (ASMS) and native MS, our method is easy to operate and interpret the data. Undoubtedly, it provides a new methodology for potential drug discovery in NPs, and will accelerate the research on screening ligands for specific proteins from complex NPs.
Self-trapping excitons (STEs) emission in metal halides has been a matter of interest, correlating with the strength of electron-phonon coupling in the lattice, which are usually caused by ions with ns2 electronic structure. In this work, Sb3+/Te4+ ions doped Zn-based halide single crystals (SCs) with two STEs emissions have been synthesized and the possibility of its anti-counterfeiting application was explored. Further, the relationship between the strength of electron-phonon coupling and photoluminescence quantum yields (PLQYs) for STEs in a series of metal halides has been studied. And the semi-empirical range of the Huang-Rhys factors (S) for metal halides with excellent photoluminescence (PL) property has been summarized. This work provides ideas for further research into the relationship between luminescence performance and electron-phonon coupling of metal halides, and also provides a reference for designing the metal halides with high PLQYs.
In the field of lithium-ion battery cathode materials, lithium-rich layered oxide materials have garnered significant attention due to their exceptional discharge specific capacity and high operating voltage. However, their limitations in terms of cycling stability and rate capability remain major impediments to their wider application. In this study, an innovative approach was employed by simultaneously utilizing the acidic and oxidative properties of phosphomolybdic acid to generate a spinel structure and in-situ coating of a conductive polymer (polypyrrole) on the surface of lithium-rich layered oxide materials. This strategy aimed to mitigate structural degradation during charge-discharge cycles, enhance the ionic/electronic conductivity, and suppress side reactions. Experimental results demonstrated that after 200 cycles at a current density of 1 C, the modified sample exhibited a discharge specific capacity of 193.4 mAh/g, with an improved capacity retention rate of 83.3% and a minimal voltage decay of only 0.27 V. These findings provide compelling support for the development and application of next-generation high-performance lithium-ion batteries.
Redox dyshomeostasis is a critical factor in the initiation of numerous diseases, making the accurate evaluation of the redox status of the cellular environment an important aspect of physiological research. However, maintaining redox homeostasis relies on a complex and dynamic physiological system involving multiple substrate-enzyme interactions, so its accurately detection remains a challenge. With this research, we developed an activable fluorescence switching platform by incorporating different conjugate acceptors to a fluorophore using ester bonds and resulting in fluorescence quenching due to donor-excited photo-induced electron transfer (d-PeT), which was confirmed through density functional theory calculations. The reaction-based probe was deployed for recognizing all major intracellular reducing sulfur species (RSS), including H2S, cysteine (Cys), homocysteine (Hcy), glutathione (GSH), and protein free thiols. The quenched fluorescence was significantly recovered by RSS, through releasing the fluorophore and diminishing the d-PeT effect. Furthermore, the fluorescent probe was used for the sensing and imaging RSS in living cells, demonstrating good cell-permeability, low cytotoxicity, and negative correlation with reactive oxygen species content, enabling the evaluating of global thiols redox state in HepG2 cellular lines during ferroptosis processes.
Cobalt sulfide has received widespread attention in the advanced oxidation treatment of wastewater, and its catalytic activity is influenced by crystal structure and exposed active sites. This work successfully constructed three types of cobalt sulfides, namely Co9S8, Co3S4 and CoS2, by changing the molar ratio of cobalt to sulfur. The results showed that the degradation efficiency of Co9S8, Co3S4 and CoS2 on chloroxylenol by activated peroxomonosulfate (PMS) were 100%, 88.70% and 67.73%, respectively. Combined with density functional theory (DFT), the structural properties and reaction energy barriers of different cobalt-sulfur ratios were calculated. As the ratio of cobalt to sulfur increases, the sulfur vacancies realized a fuller exposure of active sites (Co2+surf.) on the surface of the catalysts, with a highly linear relationship with the reaction rate constant (R2 = 0.945). This work explores the structure-activity relationship between cobalt sulfur ratio and degradation efficiency, which can guide new catalyst synthesis.
Electrocatalytic reduction of NO (NORR) is an effective method for NH3 synthesis, due to low bonding energy of NO bond. In this work, we have investigated many CrS2 based catalysts, including pristine CrS2, CrS2 with one S vacancy (v-CrS2), and Ti doped CrS2 (Ti@CrS2). The results have shown that the pristine CrS2 exhibits inert character for NO activation. However, v-CrS2 and Ti@CrS2 can exhibit enhanced interaction with NO, due to increased charge transfer between NO and substrates (0.52–0.75 e) and enhanced adsorption energies of NO on the catalysts (-0.96~-1.64 eV), compared to the situation of CrS2 (0.065 e/-0.30 eV). From the free energy profiles of NO electro-reduction to NH3, we can see that the v-CrS2 and Ti@CrS2 all exhibit ultralow limiting potentials of -0.03~-0.47 V, following both *NOH and *NHO mechanisms. Therefore, introducing vacancy and doping are all promising modification strategies for NORR catalysts. The results have provided a new idea for the search of catalysts for efficient electrocatalytic reduction of NO.
Hyperforatone A (1), the 1,8-seco rearranged polycyclic polyprenylated acylphloroglucinol, possessed an unusual bicyclo[5.4.0]undecane skeleton bearing a 5/7/6/5 ring system, and two known biosynthetically related precursors (2 and 3) were isolated from Hypericum perforatum (St. John’s wort). The structure and absolute configuration were unambiguously confirmed by a combination of comprehensive spectroscopic data, computational methods including residual dipolar couplings (RDCs), and X-ray crystallography. Density functional theory (DFT) calculations revealed that the cationic cyclization reaction was key to proposed formation mechanism for hyperforatone A. Furthermore, in vitro and in vivo experiments demonstrated that compound 1 was a potential anti-neuroinflammatory agent.
A binary-mixed electron transport layer (ETL) has been reported for constructing solution-processable near-infrared organic light-emitting diodes (NIR OLEDs). Relative to the single-component ETL, the binary-mixed ETL composed of PDINN:TPBi can enhance the carrier transport capacity, reduce device impedance, and weaken fluorescence quenching of the emitting layer. By carefully selecting an appropriate luminescent material Y5 (a nonfullerene electron acceptor in organic solar cells) and precisely fine-tuning the molecular aggregation in active layer using a mixed solvent, the morphology is optimized and luminescence performance is enhanced, resulting in efficient NIR OLEDs with an emission peak at 890 nm. The experiment showcases a Y5-based near-infrared OLED with a maximum radiance of 34.9 W sr-1 m-2 and a maximum external quantum efficiency of 0.50%, which is among the highest values reported for non-doped fluorescent NIR OLEDs with an emission peak over 850 nm.
Carbon materials are considered as prospective anode candidates for potassium ion batteries (PIBs). However, the low-rate capability is hampered by slow K+ diffusion kinetics and obstructed electron transport of carbon-based anodes. In this work, calcium d-gluconate derived mesoporous carbon nanosheets (CGC) were interpenetrated into the architecture of reduced graphene oxides (RGO) to form the composites of two-dimensional (2D)/2D graphene/mesoporous carbon nanosheets (RGO@CGC). CGC as a rigid skeleton can prevent the graphene layers from restacking and maintain the structural stability of the 2D/2D carbon composites of RGO@CGC. The mesopores in CGC can shorten the path of ion diffusion and facilitate the penetration of electrolytes. RGO possesses the high surface-to-volume ratio and superior electron transport capability in the honeycomb-like 2D network consisting of sp2-hybridized carbon atoms. Especially, the π-π stacking interaction between CGC and RGO enhances stable composite structure formation, expedites interlayer-electron transfer, and establishes three-dimensional (3D) ion transportation pathways. Owing to these unique structure, RGO@CGC exhibits fast and stable potassium storage capability. Furthermore, the effects of binders and electrolytes on the electrochemical performance of RGO@CGC were investigated. Finally, Prussian blue was synthesized as a positive electrode to explore the possibility of RGO@CGC as a full battery application.
Unraveling the essence of electronic structure effected by d-d orbital coupling of transition metal and methanol oxidation reaction (MOR) performance can fundamentally guide high efficient catalyst design. Herein, density functional theory (DFT) calculations were performed at first to study the d–d orbital interaction of metallic PtPdCu, revealing that the incorporation of Pd and Cu atoms into Pt system can enhance d-d electron interaction via capturing antibonding orbital electrons of Pt to fill the surrounding Pd and Cu atoms. Under the theoretical guidance, PtPdCu medium entropy alloy aerogels (PtPdCu MEAAs) catalysts have been designed and systematically screened for MOR under acid, alkaline and neutral electrolyte. Furthermore, DFT calculation and in-situ fourier transform infrared spectroscopy analysis indicate that PtPdCu MEAAs follow the direct pathway via formate as the reactive intermediate to be directly oxidized to CO2. For practical direct methanol fuel cells (DMFCs), the PtPdCu MEAAs-integrated ultra-thin catalyst layer (4–5 µm thickness) as anode exhibits higher peak power density of 35 mW/cm2 than commercial Pt/C of 20 mW/cm2 (~40 µm thickness) under the similar noble metal loading and an impressive stability retention at a 50-mA/cm2 constant current for 10 h. This work clearly proves that optimizing the intermediate adsorption capacity via d-d orbital coupling is an effective strategy to design highly efficient catalysts for DMFCs.
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