Electrostatic interaction

静电相互作用
  • 文章类型: Journal Article
    全氟烷基和多氟烷基物质(PFAS)由于其在环境中的广泛分布及其对人类健康的潜在毒理学影响而受到了相当多的科学和监管审查。土壤圈是这些化学物质的重要蓄水池,显著决定了它们的环境轨迹和化学转化。这项研究提供了有关PFAS在土壤基质中的吸附力学的当前理解的全面综合。由于其独特的分子结构,在土壤吸附过程中,PFAS主要参与疏水和静电相互作用。这项工作彻底评估了各种因素对吸附效率的影响,包括土壤性质,PFAS的分子特征,和当前的环境条件。土壤环境的复杂性使隔离个体对PFAS行为的影响变得复杂,需要采取综合方法来更好地了解他们的环境命运。通过这次探索,我们试图阐明调节土壤中PFASs吸附的因素之间复杂的相互作用,强调了未来研究的迫切需要,以解开控制PFAS化合物环境行为的复杂和组合效应。
    Per- and polyfluoroalkyl substances (PFASs) have garnered considerable scientific and regulatory scrutiny due to their widespread distribution across environments and their potential toxicological impacts on human health. The pedosphere serves as a vital reservoir for these chemicals, significantly determining their environmental trajectory and chemical transformations. This study offers a comprehensive synthesis of the current understanding regarding the adsorption mechanics of PFASs in soil matrices. Due to their unique molecular structure, PFASs predominantly engage in hydrophobic and electrostatic interactions during soil adsorption. This work thoroughly evaluates the influence of various factors on adsorption efficiency, including soil properties, molecular characteristics of PFASs, and the prevailing environmental conditions. The complex nature of soil environments complicates isolating individual impacts on PFAS behavior, necessitating an integrated approach to understanding their environmental destinies better. Through this exploration, we seek to clarify the complex interplay of factors that modulate the adsorption of PFASs in soils, highlighting the urgent need for future research to disentangle the intricate and combined effects that control the environmental behavior of PFAS compounds.
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  • 文章类型: Journal Article
    随着COVID-19大流行的继续,传染性更强的SARS-CoV-2变种,包括Omicron,已经出现了。突变,尤其是那些发生在刺突(S)蛋白受体结合域(RBD),由于它们增加病毒感染性的潜在能力,毒力,和突破性的抗体保护。然而,SARS-CoV-2突变病理生理改变的分子机制仍然知之甚少。这里,我们总结了21个RBD突变及其人血管紧张素转换酶2(hACE2)和/或中和抗体的结合特性.我们发现大多数RBD突变,这可能会增加表面正电荷或极性,增强其hACE2结合亲和力和免疫逃避。基于病毒表位残基与对接蛋白(如病毒受体或抗体)的静电相互作用对其入侵的依赖性,我们推测S蛋白RBD结构域上新突变的电荷和/或极性变化会影响其对hACE2和抗体的亲和力。因此,我们对突变体S三聚体和RBD-hACE2复合物进行了建模,并计算了它们的电分布以研究表面电荷的变化。同时,我们强调硫酸乙酰肝素蛋白聚糖(HSPG)可能在hACE2介导的SARS-CoV-2进入细胞中起重要作用。这些假设提供了一些关于SARS-CoV-2突变如何增强病毒适应性和免疫逃避的提示,这可能表明药物设计的潜在方法,下一代疫苗的开发,和抗体疗法。
    With the COVID-19 pandemic continuing, more contagious SARS-CoV-2 variants, including Omicron, have been emerging. The mutations, especially those that occurred on the spike (S) protein receptor-binding domain (RBD), are of significant concern due to their potential capacity to increase viral infectivity, virulence, and breakthrough antibodies\' protection. However, the molecular mechanism involved in the pathophysiological change of SARS-CoV-2 mutations remains poorly understood. Here, we summarized 21 RBD mutations and their human angiotensin-converting enzyme 2 (hACE2) and/or neutralizing antibodies\' binding characteristics. We found that most RBD mutations, which could increase surface positive charge or polarity, enhanced their hACE2 binding affinity and immune evasion. Based on the dependence of electrostatic interaction of the epitope residue of virus and docking protein (like virus receptors or antibodies) for its invasion, we postulated that the charge and/or polarity changes of novel mutations on the RBD domain of S protein could affect its affinity for the hACE2 and antibodies. Thus, we modeled mutant S trimers and RBD-hACE2 complexes and calculated their electrotactic distribution to study surface charge changes. Meanwhile, we emphasized that heparan sulfate proteoglycans (HSPGs) might play an important role in the hACE2-mediated entry of SARS-CoV-2 into cells. Those hypotheses provide some hints on how SARS-CoV-2 mutations enhance viral fitness and immune evasion, which may indicate potential ways for drug design, next-generation vaccine development, and antibody therapies.
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  • 文章类型: Journal Article
    微塑料(MPs)被定义为尺寸<5mm的颗粒,其特征在于疏水性和大表面积。在水生和陆地环境中,MPs通过吸附-解吸过程与共存的疏水性有机污染物(HOC)相互作用。活生物体摄入MPs可能会增加HOC水平的暴露。HOCs吸附到MPs上的关键机制是疏水相互作用,静电相互作用,π-π相互作用,氢键,和范德华力(vdW)。聚合物类型,紫外光诱导的表面改性,含氧官能团的形成对静电和氢键相互作用有较大影响。相比之下,含氧官能团的形成对疏水相互作用有负面影响。MP特性,如结晶度,风化,和表面形貌影响吸附能力。基质特性,如pH,离子强度,和溶解有机物(DOM)也通过发挥协同/拮抗作用来影响吸附能力。我们回顾了HOC吸附到MPs上的机理以及影响HOC吸附的聚合物和基质特性。概述了知识差距和未来的研究方向。
    Microplastics (MPs) have been defined as particles of size < 5 mm and are characterized by hydrophobicity and large surface areas. MPs interact with co-occurring hydrophobic organic contaminants (HOCs) via sorption-desorption processes in aquatic and terrestrial environments. Ingestion of MPs by living organisms may increase exposure to HOC levels. The key mechanisms for the sorption of HOCs onto MPs are hydrophobic interaction, electrostatic interaction, π-π interactions, hydrogen bonding, and Van der Waals forces (vdW). Polymer type, UV-light-induced surface modifications, and the formation of oxygen-containing functional groups have a greater influence on electrostatic and hydrogen bonding interactions. In contrast, the formation of oxygen-containing functional groups negatively influences hydrophobic interaction. MP characteristics such as crystallinity, weathering, and surface morphology affect sorption capacity. Matrix properties such as pH, ionic strength, and dissolved organic matter (DOM) also influence sorption capacity by exerting synergistic/antagonistic effects. We reviewed the mechanisms of HOC sorption onto MPs and the polymer and matrix properties that influence the HOC sorption. Knowledge gaps and future research directions are outlined.
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  • 文章类型: Journal Article
    评论文章致力于全面研究蛋白水解酶胰腺胰蛋白酶在壳聚糖基聚合物基质及其衍生物中固定过程中形成的化学键。研究的主要重点是描述导致基于壳聚糖的载体和胰蛋白酶之间固定的化学键。因为载体和胰蛋白酶之间的化学键的性质是决定缀合物的应用领域的关键因素。已经发现,在官能团的化学性质之后,它们的电离程度,化学交联的结构,改性壳聚糖的介质pH值和离子强度,胰蛋白酶固定化的机制受到影响。因此,对基质的吸引酶是由于极性共价键和氢键而发生的,以及静电,疏水,范德华部队.所收集的关于将胰蛋白酶固定在壳聚糖基载体上的研究工作已在论文中系统化,并根据化学相互作用的类型在子系统中进行了示意性显示。已经表明,由于蛋白质和载体之间的共价键和氢键,胰蛋白酶在基于壳聚糖的基质上的固定更经常发生。
    The review article is dedicated to a comprehensive study of the chemical bond formed during the immobilization of the proteolytic enzyme pancreatic trypsin in chitosan-based polymer matrixes and its derivatives. The main focus of the study is to describe the chemical bond that causes immobilization between chitosan based carriers and trypsin. Because the nature of the chemical bond between the carrier and trypsin is a key factor in determining the area of application of the conjugate. It has been found out that after the chemical nature of functional groups, their degree of ionization, the structure of the chemical cross-linking, the medium pH and ionic strength of chitosan are modified, the mechanism of trypsin immobilization is affected. As a result, the attraction enzyme to the matrix occurs due to polar covalent and hydrogen bonds, as well as electrostatic, hydrophobic, Van der Waals forces. The collected research works on the immobilization of trypsin on chitosan-based carriers have been systematized in the paper and shown schematically in subsystems according to the type of chemical interaction. It has been shown that the immobilization of trypsin on chitosan based matrixes occur more often due to the covalent and hydrogen bonds between the protein and the carrier.
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  • 文章类型: Journal Article
    Egg white protein (EWP) was one of the high-quality protein sources and widely used in the food industries because of excellent emulsifying, gelling, and foaming properties. Polysaccharides as a natural biological macromolecule have been used to improve the functional properties of EWP. The electrostatic interaction was the main driving force between EWP and polysaccharides. However, protein-polysaccharides complexes were susceptible to environmental factors including pH, ionic strength, polymer ratio, and temperature. In this paper, the functional properties of EWP were summarized. More importantly, the effects of polysaccharides on the functional properties of EWP were highlighted and reviewed referring to emulsifying, foaming, and gelling properties. The impact of environmental factors on the protein-polysaccharides interaction were also discussed. This paper leaded to enrich research systems of protein-polysaccharides interaction and provided information for the development of new egg white-derived foods.
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  • 文章类型: Journal Article
    Polyphenol-based materials are of wide-spread interest because of the unique properties of the polyphenol itself. Tannic acid, contains high level of galloyl groups, could be coordinated to a range of metal ions to generate robust mental ion-TA films on substrate or even forming hollow capsules. These films or capsules can be used in the field of sensing, separation and catalysis, most importantly in drug/nutraceutical delivery, allowing for the high loading efficiency, high mechanical and thermal stability, pH-responsive disassembly and fluorescence behavior. Additionally, such coating could also provide protection of the sensitive molecules and cells. With the numerous carbonyl and phenolic functional groups, TA has also been demonstrated to form strong hydrogen bonded multilayers with various non-ionic polymers. The properties of the hydrogen-bonded system were highly influenced by the chemical structure of the polymers, which will change the behavior of pH-, temperature- or ionic strength-responsive release of the loading molecules. Additionally, the ionization of galloyl phenol group was attributed to the interaction between TA and other ionic polymers by electrostatic interaction. The electrostatic interaction/hydrogen bonding derived TA/polyme$$%r complexes could deposit on glass slides, microcores or even forming hollow capsules, promising in their applicability to nutraceutical encapsulation, delivery and depot. Notably, polyphenols self-polymerizing could also deposit coatings on different substrates without any exogenous additives, while the comprehensive undertanding about the self-polymerizing mechenism remains unclear. This review provides a promising prospect for utilizing polyphenol-based materials to design versatile architecture in different system, used in the field of chemistry and materials science.
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  • 文章类型: Journal Article
    Perfluorinated compounds (PFCs) have drawn great attention recently due to their wide distribution in aquatic environments and potential toxic to animals and human beings. Adsorption not only is an effective technology to remove PFCs from water or wastewater, but also affects PFC distribution at solid-liquid interfaces and their fate in aquatic environments. This article reviews the adsorption behavior of different PFCs (mainly perfluorooctane sulfonate and perfluorooctanoate) on various adsorptive materials. Some effective adsorbents are introduced in detail in terms of their preparation, characteristics, effects of solution chemistry and PFC properties on adsorption. Adsorption mechanisms of PFCs on different adsorbents are summarized, and various interactions including electrostatic interaction, hydrophobic interaction, ligand exchange, and hydrogen bond are fully reviewed. The adsorbents with amine groups generally have high adsorption capacity for PFCs, and formation of micelles/hemi-micelles plays an important role in achieving high adsorption capacity of perfluorinated surfactants on some porous adsorbents. Hydrophobic interaction is mainly responsible for PFC adsorption, but the difference between PFCs and traditional hydrocarbons has not clearly clarified. This review paper would be helpful for the preparation of effective adsorbents for PFC removal and understanding interfacial process of PFCs during their transport and fate in aquatic environments.
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  • 文章类型: Journal Article
    Over the past several years, great advances have been made towards novel drug delivery systems. The phenomena of interpolymer interactions and formation of polyelectrolyte complexes have been the focus of intensive fundamental and applied research. Interpolyelectrolyte complexes combine unique physicochemical properties with high biocompatibility. Studies have been carried out on many different polymer blends and types. Such combinations may possess unique properties that are different from those of individual component. The present review emphasizes on the applicability of polyelectrolyte complexes in drug delivery technology.
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