Selective transport of cesium ion in polymeric CTA membrane containing calixcrown ethers

A series of calixcrown ethers for which the cavity size of the crown ring is varied from crown-6 to crown-7 to crown-8 were examined for the transport abilities toward alkali metal ions. These ligands were incorporated into supported liquid membranes (SLMs) and into polymer inclusion membranes (PIMs) composed of cellulose triacetate (CTA) as a support and 2-nitrophenyl octyl ether (NPOE) and tris(2-butoxyethyl) phosphate (TBEP) as a plasticizer. In both membrane systems, calixcrown-6 showed the best selectivity toward a cesium ion over other alkali metal ions. The polymeric CTA membrane showed more rapid transport rate as well as higher durability than did the SLMs.     

Coronaviruses Use ACE2 Monomers as Entry-Receptors

The angiotensin-converting enzyme 2 (ACE2) has been identified as entry receptor on cells enabling binding and infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via trimeric spike (S) proteins protruding from the viral surface. It has been suggested that trimeric S proteins preferably bind to plasma membrane areas with high concentrations of possibly multimeric ACE2 receptors to achieve a higher binding and infection efficiency. Here we used direct stochastic optical reconstruction microscopy (dSTORM) in combination with different labeling approaches to visualize the distribution and quantify the expression of ACE2 on different cells. Our results reveal that endogenous ACE2 receptors are present as monomers in the plasma membrane with densities of only 1–2 receptors μm⁻². In addition, binding of trimeric S proteins does not induce the formation of ACE2 oligomers in the plasma membrane. Supported by infection studies using vesicular stomatitis virus (VSV) particles bearing S proteins our data demonstrate that a single S protein interaction per virus particle with a monomeric ACE2 receptor is sufficient for infection, which provides SARS-CoV-2 a high infectivity.     

Interfacial Assembly of Nanocrystals on Nanofibers with Strong Interaction for Electrocatalytic Nitrate Reduction

One-dimensional fiber architecture serves as an excellent catalyst support. The orderly arrangement of active materials on such a fiber substrate can enhance catalytic performance by exposing more active sites and facilitating mass diffusion; however, this remains a challenge. We developed an interfacial assembly strategy for the orderly distribution of metal nanocrystals on different fiber substrates to optimize their electrocatalytic performance. Using electrochemical nitrate reduction reaction (NO₃⁻RR) as a representative reaction, the iron-based nanofibers (Fe/NFs) assembly structure achieved an excellent nitrate removal capacity of 2317 mg N/g Fe and N₂ selectivity up to 97.2 %. This strategy could promote the rational design and synthesis of fiber-based electrocatalysts.     

Optimizing Membranes for Osmotic Power Generation

The design of ion-selective membranes is the key towards efficient reverse electrodialysis-based osmotic power conversion. The tradeoff between ion selectivity (output voltage) and ion permeability (output current) in existing porous membranes, however, limits the upgradation of power generation efficiency for practical applications. Thus, we provide the simple guidelines based on fundamentals of ion transport in nanofluidics for promoting osmotic power conversion. In addition, we discuss strategies for optimizing membrane performance through analysis of various material parameters in membrane design, such as pore size, surface charge, pore density, membrane thickness, ion pathway, pore order, and ionic diode effect. Lastly, a perspective on the future directions of membrane design to further maximize the efficiency of osmotic power conversion is outlined.     

In Situ Spectroscopic Detection of Large-Scale Reorientations of Transmembrane Helices During Influenza A M2 Channel Opening**

Viroporins are small ion channels in membranes of enveloped viruses that play key roles during viral life cycles. To use viroporins as drug targets against viral infection requires in-depth mechanistic understanding and, with that, methods that enable investigations under in situ conditions. Here, we apply surface-enhanced infrared absorption (SEIRA) spectroscopy to Influenza A M2 reconstituted within a solid-supported membrane, to shed light on the mechanics of its viroporin function. M2 is a paradigm of pH-activated proton channels and controls the proton flux into the viral interior during viral infection. We use SEIRA to track the large-scale reorientation of M2’s transmembrane α-helices in situ during pH-activated channel opening. We quantify this event as a helical tilt from 26° to 40° by correlating the experimental results with solid-state nuclear magnetic resonance-informed computational spectroscopy. This mechanical motion is impeded upon addition of the inhibitor rimantadine, giving a direct spectroscopic marker to test antiviral activity. The presented approach provides a spectroscopic tool to quantify large-scale structural changes and to track the function and inhibition of the growing number of viroporins from pathogenic viruses in future studies.     

Photolithographically patternable nitrate-sensitive acrylate-based membrane

A photocurable acrylate matrix nitrate-sensitive membrane containing 2-nitrophenyl n-octyl ether as mediator and tetraalkylammonium nitrate as an active compound is described. The photocuring was achieved by the use of photoinitiators containing diaryliodonium chloride. This acrylate membrane is patternable via a photolithographic process with a only slight loss of electrochemical characteristics.     

Discussion of the protein characterization techniques used in the identification of membrane protein targets corresponding to tumor cell aptamers

Aptamer is an oligonucleotide chain with specific binding ability to protein and other targets,which is widely used in ma ny fields.Because of its ability to screen the premise of unknown targets,it can be used to discover some novel tumor markers,i.e.,membrane proteins that are specifically highly expressed on the surface of tumor cells.Tumor markers can be used in many fields such as early diagnosis and treatment,and a new type of tumor marker proved to be effective can significantly improve the therapeutic effect of such tumors.However,further characterization of newly acquired membrane proteins is essential for their clinical use as tumor markers.This review first briefly introduced the process of obtaining novel tumor markers from nucleic acid aptamers.Next,the commonly used protein characterization methods could be used as a technical means to identify membrane protein targets corresponding to tumor cell aptamers,to clarify the principles,advantages and disadvantages of various means,and to analyze the most suitable situations for various experimental methods.Finally,the outlook was made and the characterization methods that should be used in such experiments were summarized.     

分子筛膜反应器的研究进展

分子筛膜具有规整的微孔结构(<1 nm), 耐高温高压、 抗有机溶剂, 在液相和气相小分子分离中受到广泛关注. 分子筛膜可以与催化反应耦合于一体构成膜反应器, 使反应过程与组分分离同时进行, 促进反应平衡移动, 达到反应强化的效果. 本文概述了近十年不同类型分子筛膜反应器在催化反应中的应用研究进展, 并对分子筛膜反应器未来的发展趋势进行了展望.     

微纳米纤维素功能膜在能源与环境领域的应用

探寻绿色清洁的资源与材料以维持高效的社会经济增长是未来数十年人们面临的最大挑战之一. 可持续资源与绿色材料的开发是降低传统化石能源与材料比重的最有前途的方案. 纤维素作为一种可持续发展、 可生物再生、 储量丰富且低成本的天然高分子聚合物, 在众多领域中具有广泛的应用, 并且纤维素可以加工成各种构型, 包括气凝胶、 泡沫、 海绵和薄膜等. 本文介绍了不同形态的纤维素及其衍生物组装而成的功能膜在能源与环境中的应用, 综述了微纳米纤维素及其衍生物在先进功能化储能器件方面的最新进展和制备方案, 以及在用于水处理的膜分离技术中的应用, 其中重点讨论了微纳米纤维素及其衍生物功能膜在电池、 电容器及水处理等领域中的作用, 如隔膜、 柔性电极膜和分离膜等. 此外, 还对纤维素及其衍生物功能膜的未来发展进行了总结和展望.     

稀土掺杂上转换纳米颗粒-金属有机骨架复合材料的研究进展

稀土掺杂上转换纳米颗粒-金属有机骨架复合材料是一类新型的功能复合材料. 它不仅结合了稀土掺杂上转换纳米颗粒和金属有机骨架这两种材料的特性, 体现了两者复合后的协同效应, 还具有设计灵活和功能易拓展等优势. 本文聚焦稀土掺杂上转换纳米颗粒-金属有机框架复合材料的最新发展, 总结了该类复合材料的制备方法, 介绍了其在生物和催化等领域的应用, 并对其面临的挑战和发展前景进行了展望.