Latest ArticlesLithium-sulfur (Li-S) battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity (1673 mAh/g), high energy density (2500 Wh/kg), low cost, and environmentally friendliness of sulfur. However, critical drawbacks, including inherent low conductivity of sulfur and Li2S, large volume changes of sulfur cathodes, undesirable shuttling and sluggish redox kinetics of polysulfides, seriously deteriorate the energy density, cycle life and rate capability of Li-S battery, and thus limit its practical applications. Herein, we reviewed the recent developments addressing these problems through iron-based nanomaterials for effective synergistic immobilization as well as conversion reaction kinetics acceleration for polysulfides. The mechanist configurations between different iron-based nanomaterials and polysulfides for entrapment and conversion acceleration were summarized at first. Then we concluded the recent progresses on utilizing various iron-based nanomaterials in Li-S battery as sulfur hosts, separators and cathode interlayers. Finally, we discussed the challenges and perspectives for designing high sulfur loading cathode architectures along with outstanding chemisorption capability and catalytic activity.
Fast-charging is considered to be a key factor in the successful expansion and use of electric vehicles. Current lithium-ion batteries (LIBs) exhibit high energy density, enabling them to be used in electric vehicles (EVs) over long distances, but they take too long to charge. In addition to modifying the electrode and battery structure, the composition of the electrolyte also affects the fast-charging capability of LIBs. This review provides a comprehensive and in-depth overview of the research progress, basic mechanism, scientific challenges and design strategies of the new fast-charging solution system, focusing on the influences that the compositions of liquid and solid electrolytes have on the fast-charging performance of LIBs. Finally, new insights, promising directions and potential solutions for the electrolytes of fast-charging systems are proposed to stimulate further research on revolutionary next-generation fast-charging LIB chemistry.
Respiratory antibiotics have been proven clinically beneficial for the treatment of severe lung infections such as Pseudomonas aeruginosa. Maintaining a high local concentration of inhaled antibiotics for an extended time in the lung is crucial to ensure an adequate antimicrobial efficiency. In this study, we aim to investigate whether an extended exposure of ciprofloxacin (CIP), a model fluoroquinolone drug, in the lung epithelial lining fluid (ELF) could be achieved via a controlled-release formulation strategy. CIP solutions were intratracheally instilled to the rat lungs at 3 different rates, i.e., T0h (fast), T2h (medium), and T4h (slow), to mimic different release profiles of inhaled CIP formulations in the lung. Subsequently, the concentration-time profiles of CIP in the plasma and the lung ELF were obtained, respectively, to determine topical exposure index (ELF-Plasma AUC Ratio, EPR). The in silico PBPK model, validated based on the in vivo data, was used to identify the key factors that influence the disposition of CIP in the plasma and lungs. The medium and slow rates groups exhibited much higher EPR than that fast instillation group. The ELF AUC of the medium and slow instillation groups were about 200 times higher than their plasma AUC. In contrast, the ELF AUC of the fast instillation group was only about 20 times higher than the plasma AUC. The generated whole-body PBPK rat model, validated by comparison with the in vivo data, revealed that drug pulmonary absorption rate was the key factor that determined pulmonary absorption of CIP. This study suggests that controlled CIP release from inhaled formulations may extend the exposure of CIP in the ELF post pulmonary administration. It also demonstrates that combining the proposed intratracheal installation model and in silico PBPK model is a useful approach to identify the key factors that influence the absorption and disposition of inhaled medicine.
MicroRNA-26a (miR-26a) has been verified to promote osteogenic differentiation of mesenchymal stem cells in recent years. The main obstacles to its application in bone regeneration are instability in the physiological environment and low efficiency of cellular membrane penetration. To overcome these problems, we constructed a novel plant virus gene delivery system based on Cowpea chlorotic mottle virus (CCMV). By encapsulating miR-26a with purified capsid protein (CP) dimers derived from CCMV, CP-miR-26a (CP26a) virus-like particles (VLPs) were obtained. CP26a retained a structure similar to the native CCMV and protected miR-26a from digestion with its exterior CP. Moreover, CP26a featured similar cellular uptake efficiency, osteogenesis promotion ability, and better biocompatibility compared with Lipofectamine2000-miR-26a (lipo26a), which indicated a promising prospect for CCMV as a novel gene delivery system.
Taking advantage of the Warburg effect in cancer cells, glucose conjugation has emerged as a useful strategy for targeted delivery of anticancer agents. Pristimerin is a naturally occurring triterpenoid that displays potent but non-selective cytotoxicity. We developed a convergent and modular approach to construction of glucose−payload conjugates featuring copper-mediated azide−alkyne cycloaddition and prepared a glucose conjugate of pristimerin through this approach. The anticancer activity of this conjugate was evaluated in cancer cells and normal cells; however, the selectivity toward cancer cells was not significantly improved. We then examined the extracellular stability of the conjugate and found that its ester linkage was cleaved rapidly in Dulbecco's Modified Eagle's Medium at 37 ℃, which resulted in the release of pristimerin. In fact, the inorganic components in this medium were sufficient to induce the cleavage. Given that the subtle difference between intrinsic stability and extracellular stability of the conjugate linker is often underappreciated, this work highlights the importance of the latter in the development of target-selective conjugates.
Developing convenient, fast-response and high-performance formaldehyde detection sensor is significant but challenging. Herein, two CeO2 phases (Fm3m and P42/mnm), three facets (CeO2(100), CeO2(110) and CeO2(111)) and three adsorption sites (top, bridge and hollow) are selected as substrate to interact with formaldehyde. Twenty-eight candidated transition metals (TM) are doped on CeO2 surfaces to investigate the performance of detecting formaldehyde by density functional theory. It shows that (ⅰ) CeO2 in a cubic fluorite structure with the space group Fm3m is suitable for formaldehyde adsorption compared with P42/mnm; (ⅱ) TM-CeO2(100) (TM = Au, Hf, Nb, Ta, Zr) are considered as candidated materials to absorb formaldehyde ascribed to lower adsorption energies. The d-band center, partial density of states, charge density difference and electron localization function are employed to clarify the mechanism of TM-doped CeO2 improving the performance of formaldehyde adsorption. It obviously displays that TM doped CeO2(100) changes the d orbit and rearranges electrons resulting in the superior ability to the adsorbed formaldehyde. This work provides theoretical guidance and experimental motivation for the development of novel formaldehyde sensor based on metal oxide semiconductor materials.
Polyaniline-supported tungsten (W@PANI) was easily prepared by immersing polyaniline (PANI) in the aqueous solution of Na2WO4. It was found to be an efficient catalyst for oxidative deoximation reaction, the very important transformation for pharmaceutical industry. Besides the green features, the method employed very few of catalytic tungsten (0.048 mol% vs. oxime substrates), resulting in the high turnover numbers (TONs) of the catalyst (ca. 103 mol/mol) and the low metal residues in product (< 0.1 ppm). The reaction is applicable for a variety of substrates, including those containing heterocycles, which are key intermediates in medicine synthesis. It has also been successfully magnified to kilogram scale production to afford the desired carbonyl products smoothly.
Nine new fluorine-containing drugs have been approved by the US Food and Drug Administration (FDA) in 2021, which are presented in this review article. These small molecular drugs feature aromatic fluorine, trifluoromethyl and chlorodifluoro groups. The therapeutic areas of these fluorine-containing drugs include multiple myeloma, lymphoma, HIV, chronic heart failure, chronic myeloid leukemia, (ANCA)-associated vasculitis, migraines, von Hippel-Lindau disease, and non-small cell lung cancer. The brief biological activities and the synthetic methods have been discussed in this review for each of these nine drugs.
The fluorescence lifetime of nicotinamide adenine dinucleotide (NADH), a key endogenous coenzyme and metabolic biomarker, can reflect the metabolic state of cells. To implement metabolic imaging of brain tissue at high resolution, we assembled a two-photon fluorescence lifetime imaging microscopy (FLIM) platform and verified the feasibility and stability of NADH-based two-photon FLIM in paraformaldehyde-fixed mouse cerebral slices. Furthermore, NADH based metabolic state oscillation was observed in cerebral nuclei suprachiasmatic nucleus (SCN). The free NADH fraction displayed a relatively lower level in the daytime than at the onset of night, and an ultradian oscillation at night was observed. Through the combination of high-resolution imaging and immunostaining data, the metabolic tendency of different cell types was detected after the first two hours of the day and at night. Thus, two-photon FLIM analysis of NADH in paraformaldehyde-fixed cerebral slices provides a high-resolution and label-free method to explore the metabolic state of deep brain regions.