手性膜材料及分离机制研究进展

手性膜分离法作为一种新兴的手性分离技术，具有高效、简便、低能耗、可连续操作等特点，在手性分离领域具有巨大的潜力。但近几十年的研究表明，传统手性聚合物材料选择性差、渗透通量低、稳定性差，且难以打破选择性与渗透通量之间的制约关系。这是膜拆分性能无法大幅提高的症结所在，导致膜分离领域长时间处于发展的瓶颈期。近年来，已有许多学者针对这些问题，寻找手性位点更加丰富、稳定性更强、能够提供更多分子通道的新型材料。重点介绍了近5年来基于碳纳米材料、金属有机框架(MOF)、共价有机框架(COF)、改良手性聚合物和一些其他无机材料的新型手性固体膜的合成和应用，并对这些材料的优缺点进行了总结和讨论，以期推动固体膜手性分离技术的进步。另外，还对膜分离机制的研究进展进行了总结，并特别讨论了新材料在手性膜中的作用机制，为进一步改善膜拆分性能提供理论基础。     

万古霉素手性膜色谱的研究

以聚醚砜膜作为基膜,以万古霉素、1,6-己二异腈酸酯作为单体,利用界面聚合的方法制备了万古霉素-己二异腈酸酯聚醚砜手性高分子复合膜,使用自制的膜色谱装置结合高效液相色谱仪,对手性物质D,L-苯甘氨酸进行了手性膜色谱分离研究.详细研究了流速、流动相、进样量、膜层数、膜尺寸对拆分效果的影响.在优选分离条件下,该手性膜色谱对D,L-苯甘氨酸拆分的分离因子(α)和分离度(R_s)分别为5.66、0.66,该方法的最大优点是在水环境下能对手性化合物进行分离制备,这在色谱的手性分离中是少见的.     

甲壳素和壳聚糖膜材料的研究进展

本文综述了甲壳素和壳聚糖及它们的衍生物制备反渗透膜、超滤膜、渗透汽化和蒸发渗透膜的最新进展，可能是一类很有发展前途的天然高分子膜材料。     

淀粉苯基氨基甲酸酯类手性固定相的制备及用于HPLC手性体分离性能的研究

合成了含有3,5-二甲基和3,5-二氯取代基团的混合型淀粉(苯基氨基甲酸酯)衍生物(CSP-2),并作为手性体分离材料涂敷在氨丙基化多孔硅胶表面,制得新型高效液相色谱(HPLC)用手性固定相;通过1H核磁共振(1H NMR)和红外光谱(IR)表征衍生物结构;以正己烷-异丙醇(9∶1,v/v)为流动相,对多种手性对映体进行了拆分;结果表明,CSP-2综合了单一取代基团淀粉(苯基氨基甲酸酯)衍生物的手性拆分性能,具有优越的手性分离能力,同时固定相的稳定性大大增强。     

HPLC用苯基氨基甲酸酯类手性固定相的制备及分离性能

合成了同时含有3,5-二甲基和3,5-二氯取代基团的纤维素(苯基氨基甲酸酯)衍生物(CSP-1),作为手性体分离材料涂敷在氨丙基化硅胶表面,制得新型高效液相色谱(HPLC)用手性固定相;利用1H核磁共振(1H-NMR)和红外光谱(IR)表征了衍生物结构;以正己烷-异丙醇(体积比9∶1)为流动相,对多种手性对映体进行了拆分。结果表明,CSP-1具有很好的手性体分离能力,综合了单一取代基团纤维素(苯基氨基甲酸酯)衍生物的手性拆分性能。     

基于壳聚糖的分子印迹技术研究及应用

分子印迹技术是一种新兴的分子识别技术,该技术可以制备具有特异选择性识别能力的聚合物,凭借其高度的专一性、稳定性以及可重复性等特点,逐渐成为了研究热点。壳聚糖是一种环境友好、来源丰富且可循环再生的天然高分子化合物,其分子结构中的氨基等官能团具有较强的活性,使壳聚糖具有生物降解性、细胞亲和性和生物效应等多种独特的性质,在医学、食品、环保等领域广泛应用。壳聚糖的官能团反应活性强,易进行改性或化学修饰,因此以壳聚糖及其衍生物为功能单体或载体,结合分子印迹技术,易制备具有理想的亲和性和稳定性、高印迹效率、强选择性的新型分子印迹聚合物,从而提高壳聚糖材料的性能,拓宽其应用领域和范围。本文根据近年来国内外学者在壳聚糖分子印迹改性领域的研究进展,对壳聚糖及其衍生物在分子印迹聚合物制备中的作用、分子印迹聚合物制备方法以及常用交联剂的类型进行总结,详细阐述了壳聚糖分子印迹聚合物在重金属污染物处理、生物医学、固相萃取、蛋白质识别、电化学传感器、手性物质分离等方面的应用,分析了壳聚糖分子印迹聚合物在各领域应用的优缺点,并展望了壳聚糖分子印迹技术的发展方向。     

L-色氨酸分子印迹膜的表征、识别性能及识别机理

以L-色氨酸为模板分子,甲基丙烯酸为功能单体,聚砜为基膜,采用紫外光接枝法制备L-色氨酸手性分子印迹固膜.用扫描电镜和原子力电子显微镜对固膜的形貌进行表征,并对其特异性吸附性能及识别机理进行研究.固膜的手性分离因子高达4.1,由Scatchard模型分析分子印迹固膜与模板分子之间的结合作用力以氢键作用为主.     

壳寡糖及其应用

壳聚糖是甲壳素脱乙酰化后的产物,壳寡糖为壳聚糖的降解产物。壳聚糖及其衍生物就是一类具有重要生理功能的天然氨基多糖。壳寡糖的性质、功能及生理活性等方面的研究已经成为糖生物学科学研究中的热门领域之一。     

具有手性分离功能的MOCPs的构建

就手性在药物分离中的重要性及手性分离剂的分离机制进行了概述.以此为基础,对一类在手性分离领域有巨大发展潜力的功能材料--金属有机络合聚合物(MOCPs)在分子设计和合成方面的研究现状进行了综述.MOCPs优异的理化性能、孔结构特性和手性分离功能可通过其构建分子的选择和修饰进行设计,其手性结构可通过手性配体与非手性配体进行构建.MOCPs有望在手性分离,特别是在手性药物分离领域形成新的研究和应用的热点.     

S-布洛芬分子印迹膜的制备与手性拆分性能

采用聚偏氟乙烯(PVDF)中空纤维膜为支撑体,制备了S-布洛芬分子印迹膜,并对膜的选择结合性及手性拆分性能进行了研究。研究结果表明,S-布洛芬分子印迹复合膜对S-布洛芬具有较好的选择结合性,在膜上的结合量达到22.8μmol/g。膜的错流过滤实验表明,S-布洛芬透过膜的速率大于R-布洛芬,分离因子为1.17,这将有利于外消旋布洛芬的分离。扫描电镜(SME)也同样表明,在膜的表面涂上了一薄层印记膜。     

Polycrystalline Advanced Microporous Framework Membranes for Efficient Separation of Small Molecules and Ions

Advanced porous framework membranes with excellent selectivity and high permeability of small molecules and ions are highly desirable for many important industrial separation applications. There has been significant progress in the fabrication of polycrystalline microporous framework membranes (PMFMs) in recent years, such as metal–organic framework and covalent organic framework membranes. These membranes possess small pore sizes, which are comparable to the kinetic diameter of small molecules and ions on the angstrom scale, very low thickness, down to tens to hundreds of nanometers, highly oriented crystalline structures, hybrid membrane structures, and specific functional groups for enhancing membrane selectivity and permeability. Recent advances in the fabrication methods of advanced PMFMs are summarized. Following this, four emerging separation applications of these advanced microporous framework membranes, including gas separation, water desalination, ion separation, and chiral separation, are highlighted and discussed in detail. Finally, a summary and some perspectives of future developments and challenges in this exciting research field are presented.     

Novel carboxymethyl derivatives of chitin and chitosan materials and their biomedical applications

Chitin and chitosan are natural biopolymers that are non-toxic, biodegradable and biocompatible. In the last decade, chitin and chitosan derivatives have garnered significant interest in the biomedical and biopharmaceutical research fields with applications as biomaterials for tissue engineering and wound healing and as excipients for drug delivery. Introducing small chemical groups to the chitin or chitosan structure, such as alkyl or carboxymethyl groups, can drastically increase the solubility of chitin and chitosan at neutral and alkaline pH values without affecting their characteristics; substitution with carboxyl groups can yield polymers with polyampholytic properties. Carboxymethyl derivatives of chitin and chitosan have shown promise for adsorbing metal ions, as drug delivery systems, in wound healing, as anti-microbial agents, in tissue engineering, as components in cosmetics and food and for anti-tumor activities. This review will focus on the preparative methods and applications of carboxymethyl and succinyl derivatives of chitin and chitosan with particular emphasis on their uses as materials for biomedical applications.     

分子印迹聚合物膜的制备及其应用

分子印迹膜兼具分子印迹与膜技术的优点,近年来已成为分子印迹技术领域研究的热点之一.首先对分子印迹技术及分子印迹膜进行了简介,继而重点对分子印迹膜的主要制备方法,包括原位聚合法、相转化法、表面修饰法和电化学聚合法等进行了评述,对现有分子印迹膜的分离性能进行了总结和分析.最后对分子印迹膜在手性物质拆分、固相萃取、农药残留检测及仿生传感等领域的应用及其研究方向进行了介绍和展望.     

Thermoresponsive PEG‐Coated Nanotubes as Chiral Selectors of Amino Acids and Peptides

A series of nanotubes with a dense layer of short poly(ethylene glycol) (PEG) chains on the inner surface are prepared by means of a coassembly process using glycolipids and PEG derivatives. Dehydration of the PEG chains by heating increases the hydrophobicity of the nanotube channel and fluorescent‐dye‐labeled amino acids are extracted from bulk solution. Rehydration of the PEG chains by cooling results in back‐extraction of the amino acids into the bulk solution. Because of the supramolecular chirality of the nanotubes, amino acid enantiomers can be separated in the back‐extraction procedure, which is detectable with the naked eye as a change in fluorescence as the amino acids are released from the nanotubes. The efficiency and selectivity of the chiral separation are enhanced by tuning the chemical features and inner diameter of the nanotube channels. For example, compared with wide nanotube channels (8 nm), narrow nanotube channels (4 nm) provide more effective electrostatic attraction and hydrogen bond interaction environments for the transporting amino acids. Introduction of branched alkyl chains to the inner surface of the nanotubes enables chiral separation of peptides containing hydrophobic amino acids. The system described here provides a simple, quick, and on‐site chiral separation in biological and medical fields.     

Chiral Materials: Progress,Applications, and Prospects

Chirality is a universal phenomenon in molecular and biological systems, denoting an asymmetric configurational property where an object cannot be superimposed onto its mirror image by any kind of translation or rotation, which is ubiquitous on the scale from neutrinos to spiral galaxies. Chirality plays a very important role in the life system. Many biological molecules in the life body show chirality, such as the “codebook” of the earth's biological diversity-DNA, nucleic acid, etc. Intriguingly, living organisms hierarchically consist of homochiral building blocks, for example, l -amino acids and d -sugars with unknown reason. When molecules with chirality interact with these chiral factors, only one conformation favors the positive development of life, that is, the chiral host environment can only selectively interact with chiral molecules of one of the conformations. The differences in chiral interactions are often manifested by chiral recognition, mutual matching, and interactions with chiral molecules, which means that the stereoselectivity of chiral molecules can produce changes in pharmacodynamics and pathology. Here, the latest investigations are summarized including the construction and applications of chiral materials based on natural small molecules as chiral source, natural biomacromolecules as chiral sources, and the material synthesized by design as a chiral source.     

Chitin and chitosan fibres: A review

Chitin is the most abundant natural amino polysaccharide and estimated to be produced annually almost as much as cellulose. It has become of great interest not only as an underutilized resource, but also as a new functional material of high potential in various fields and the recent progress in chitin chemistry is quite noteworthy. The purpose of this review is to take a closer look at fibres made of chitin and its derivatives. Based on the current research and existing products, some new and futuristic approaches, in the development of novel fibres and their applications have been thoroughly discussed.     

Chitosan based nanofibers,review

Chitin and chitosan are natural polymers with a huge potential in numerous fields, namely, biomedical, biological, and many industrial applications such as waste water treatment due to the fact that they can absorb and chelate many metal cations. Electrospinning is a growing field of research to produce submicron fibers with promising applications in biomedical fields like tissue engineering scaffolds and wound healing capabilities. Both chitin and chitosan polymers were found to be hard to electrospun, however, many researchers manage to produce nano-fibers using special solvents; for example, 90% acetic acid was found to reduce the surface tension making electrospinning feasible. Mixtures of organic acids were also experimented to produce homogenous and uniform fibers. Bigger attention was given to electrospinning of their soluble derivatives such as dibutyryl and carboxymethyl chitin. More derivatives of chitosan were investigated to produce nano-fibers such as hexanoyl, polyethyleneglycol, carboxymethyl, and a series of quaternized chitosan derivatives. The obtained nano-fibers were found to have much better qualities than normal chitosan fibers. Several polymer blends of chitin/chitosan with many commercial polymers were found to be amenable for electrospinning producing uniform beads free fibers. The review surveys the various approaches for successful electrospinning of chitin, chitosan, their derivatives, and blends with several other polymers.     

Enantiomeric Control of Intrinsically Chiral Nanocrystals

The chiral aspect of inorganic crystals that crystallize in chiral space groups has been largely ignored until recently, partly due to difficulties in characterizing the chiroptical properties of bulk crystals, and also due to the difficulty in separating (sub)micrometer-scale chiral crystal enantiomers. In recent years, the colloidal synthesis of intrinsically chiral nanocrystals (NCs) of several chiral inorganic compounds with significant enantiomeric excess has been demonstrated. This is achieved through the use of chiral molecular ligands, which bind to the atomic/ionic components of the crystals, preferentially forming one crystal enantiomorph. Here, recent progress on several aspects of these NCs is described, including the connection between ligand structure and its ability to direct NC handedness, chiral amplification in the synthesis leading to enantiopure NC samples, spontaneous symmetry breaking, the formation of NCs with chiral shapes, the connection between lattice and shape chirality and mixed contributions of atomic-scale and shape chirality to the chiroptical properties.     

Probing Adsorption Behaviors of BSA onto Chiral Surfaces of Nanoparticles

Chiral properties of nanoscale materials are of importance as they dominate interactions with proteins in physiological environments; however, they have rarely been investigated. In this study, a systematic investigation is conducted for the adsorption behaviors of bovine serum albumin (BSA) onto the chiral surfaces of gold nanoparticles (AuNPs), involving multiple techniques and molecular dynamic (MD) simulation. The adsorption of BSA onto both L‐ and D‐chiral surfaces of AuNPs shows discernible differences involving thermodynamics, adsorption orientation, exposed charges, and affinity. As a powerful supplement, MD simulation provides a molecular‐level understanding of protein adsorption onto nanochiral surfaces. Salt bridge interaction is proposed as a major driving force at protein–nanochiral interface interaction. The spatial distribution features of functional groups (? COO^?, ? NH₃⁺, and ? CH₃) of chiral molecules on the nanosurface play a key role in the formation and location of salt bridges, which determine the BSA adsorption orientation and binding strength to chiral surfaces. Sequentially, BSA corona coated on nanochiral surfaces affects their uptake by cells. The results enhance the understanding of protein corona, which are important for biological effects of nanochirality in living organisms.     

气固相法制备羟乙基甲壳素

采用气固相法,以环氧乙烷为醚化剂与碱甲壳素进行醚化反应,合成具有良好水溶性的羟乙基甲壳素。并且,羟乙基甲壳素的水溶性随醚化度提高而增加,呈线性关系。