肽基纳米材料及其应用

近年来,肽类超分子自组装合成纳米材料受到了广泛研究和关注,已成为纳米材料科学研究的前沿领域之一。肽基纳米材料因其良好的生物相容性以及结构和功能的多样性,在材料学、组织工程、生物工程及药物传递等方面展示出巨大的应用潜力。本文综述了肽类自组装纳米材料制备的最新研究进展,重点介绍了疏水性二肽、类表面活性剂多肽、Aβ多肽片段、烷基链修饰多肽等通过非共价键作用自组装形成的不同结构的纳米材料,包括纳米管、纳米纤维、纳米囊/球、纳米水凝胶等;同时,介绍了多肽自组装机理模型及其分子动力学模拟方面取得的研究成果;最后总结了肽基纳米材料在金属/半导体材料、生物传感器、组织修复材料及药物传递等领域的应用现状及今后重点研究的方向。     

π-共轭体系超分子自组装

π-共轭体系因其分子结构的可设计性以及优异的光电性质得到了广泛的研究,其超分子自组装在制备结构复杂、规则的功能纳米材料方面表现出了显著的优势,且是调控材料宏观性质的一种有效的方法.因此,π-共轭体系超分子自组装已经成为近年来信息、材料、生物等前沿领域的研究热点.本文综述了π共轭体系超分子自组装的机理、外界环境的导向作用、自组装形态以及其在光电器件、生物传感等方面的应用研究,进一步提出了该领域尚待解决的问题并对其应用前景进行了展望.     

有机凝胶自组装模板法制备纳米材料

利用溶胶一凝胶聚合过程人工模拟生物矿化进程的技术,已经融人无机材料和超分子有机化学的研究领域.小分子有机凝胶因子在溶剂中发牛自组装,形成多种形态的有机凝胶超分子结构,以其为模板,经过溶胶一凝胶过程,可以诱导转录形成各种形态的纳米材料.本文介绍了利用有机凝胶因子自组装结构为模板制备形态可控无机材料的研究进展及模板结构诱导转录的两种可能机制.     

DNA四面体结构纳米材料及其应用

基于DNA纳米技术自组装的DNA四面体纳米材料,由于结构稳定、机械性能优越、分子修饰位点丰富等特点,逐渐成为DNA纳米材料领域的研究热点。此外,该DNA四面体纳米材料只需一步热变性即可自组装形成,具有合成方法简单、产率高的优点。可通过不同的设计,利用自组装方法将功能分子修饰在DNA四面体的顶点处,包裹在其笼状孔隙结构内,镶嵌或悬挂在双螺旋的边上,甚至通过引入发卡环结构等方式智能控制其结构变化。本文综述了DNA四面体结构纳米材料的设计和自组装原理、功能化修饰方法和结构的智能化,同时介绍了DNA四面体纳米材料在分子诊断、生物成像、分子输送和靶向给药等方面的应用研究,并探讨了此类纳米材料在今后应用研究中应关注的方面。     

卟啉微纳米材料的制备及应用研究进展

综述了卟啉微纳米材料合成的制备方法,以及将其作为传感、光电器件等应用的研究进展。卟啉类化合物是广泛存在于自然界重要的生物分子,其独特的平面骨架和共轭大π结构,使之成为分子组装体系中优良的构筑基元。制备的卟啉微纳米材料因其良好的光、热稳定性,已被广泛用于分析化学、仿生、催化及材料科学等领域。     

基于主客体作用构筑的聚集诱导发光型超分子组装体 在生物医用领域的研究进展

主客体相互作用是超分子自组装过程中最重要的作用方式之一,常被用于构建多功能超分子材料.基于主客体相互作用,利用具有聚集诱导发光性质的大环主体分子或客体分子作为自组装基元,构筑具有聚集诱导发光效应的超分子体系,并将其应用于药物递送、细胞成像、生物传感等生物领域,已成为超分子化学的研究热点.从超分子组装体的发光效应分别源于主体分子和客体分子两方面,介绍了近五年来以环糊精、杯芳烃、葫芦脲、柱芳烃及其它大环为主体化合物,基于主客体作用构筑的聚集诱导发光超分子组装体,并对其在生物医用领域的研究进展进行了简要综述.     

低维聚合物纳米材料的自组装制备、性能及应用

特殊的聚合物可以通过分子间识别或分子间相互作用，自发地聚集成一定的分子结构或构筑成具有特殊结构和形状的聚集体，从而使其具有特殊的功能。这类自组装体系在微电子、新材料及生物医药等领域展现出了巨大的应用前景，已受到广泛关注。本文综述了低维聚合物纳米材料的自组装制备方法、性能和应用的最新进展。     

磺化杯芳烃的超分子组装体构筑及其功能

磺化杯芳烃具有非常强的分子键合能力, 被广泛用于水相超分子自组装研究. 介绍了磺化杯芳烃与客体阳离子形成超分子组装体的主要驱动力和形貌调控因素; 总结了包括主体诱导客体聚集、客体诱导主体聚集及主客体共组装在内的三种主要聚集模式; 并展望了其在刺激响应材料、药物传递载体、多功能超分子平台和超分子催化等领域的重要应用前景.     

DNA-多肽复合分子的设计、组装与应用

DNA-多肽复合分子作为一类新型的自组装分子受到研究人员的广泛关注。DNA分子具有可编程性、高特异性、功能多样等优点,多肽分子是一类重要的生物小分子,能够通过分子自组装形成具有不同结构的纳米材料,因此,将二者通过共价交联,可以获得具有多级自组装行为的DNA-多肽复合分子,能够实现两类重要生物分子功能的集成优化,合成具有不同结构与功能的超分子自组装材料。此外,通过酶催化、DNA杂化、DNA链置换反应等,还可实现对多肽-DNA复合分子自组装行为的动态调控,进而模拟生命系统中复杂动态的自组装结构,强化相关材料在生物、化学、材料等领域的应用。本文讨论了DNA-多肽复合分子的设计、组装与应用方面的最新进展,最后基于目前DNA-多肽复合分子存在的一些问题对DNA-多肽复合分子的研究做了展望。     

基于多肽自组装的人工金属酶

模拟酶,又称人工酶,是在分子水平上模拟天然酶活性部位的形状、大小及其微环境等结构特征的分子或分子聚集体。随着纳米科学和超分子技术的发展,构筑具有生物催化活性的超分子模拟酶已经成为科学研究和应用开发领域的热点。肽组装金属酶是以多肽分子为基本单元,在非共价作用力协同作用下形成的超分子组装体。相比其他功能性材料,肽人工金属酶的结构及生物化学性质更接近天然酶,其分子本身更利于修饰改造,且生物相容性和功能性较好,使其在模拟酶方面具有独特优势。本文总结了近年来通过多肽自组装构建人工金属酶的研究进展,重点综述了多肽组装模式、组装体微观结构、超分子结构、金属活性中心微环境以及pH值对模拟酶催化活性的影响。增加自组装微结构的稳定性、增加催化活性以及扩大由人工酶催化的反应类型是肽人工金属酶研究中的主要挑战。构筑更加稳定的肽自组装纳米结构及更加精确的活性中心以模拟天然酶的结构和活性中心是正确的策略。     

[60]富勒烯的超分子自组装研究进展

超分子自组装是发展超分子电子学的重要途径。随着纳米科学和技术的迅速发展,自组装技术已成功地应用于纳米尺度物质的维数、形貌和功能等的调控。作为构筑分子水平上一维、二维、三维有序功能结构和高有序分子聚集态结构的关键技术,超分子自组装技术有力地推动了具有优良光、电、磁性能的分子材料和纳米功能材料更深层次的研究。本文综述了超分子自组装在富勒烯科学领域的基础研究和应用,特别是对有利于自组织和自组装功能的富勒烯基衍生物的设计与合成、超分子作用力引导的具有特定结构的分子体系的可控自组装、以及富勒烯分子聚集态结构材料的光物理过程、超分子中电子转移和能量转移现象进行了描述;并对卟啉、四硫富瓦烯、碗烯和杯芳烃等一系列富π电子化合物和大环主体分子等包含[60]富勒烯的主体化合物的超分子作用和超分自组装体以及通过氢键、π-π作用、静电力和范德华力和金属配位作用形成的[60]富勒烯超分子自组装体进行了总结,对未来发展进行了展望。     

肽基超分子胶体

肽基超分子胶体是基于肽分子间超分子作用,自发形成且具有有序分子排布及规整结构,兼具传统胶体及超分子特性的组装体系。利用超分子弱相互作用构筑功能性胶体,不仅是人们对生命组装进程深入理解的有效手段,也是实现优异的超分子材料的重要途径。肽分子具有组成明确、性能可调、生物安全性高及可降解等优势,是超分子化学、胶体与界面化学领域重要的组装基元。基于肽的超分子自组装,能够实现多尺度、多功能的生物胶体的构筑,被广泛应用于医药、催化、能源等领域。如何通过对肽序列的设计及分子间作用力的调控,实现对胶体结构和功能的精确控制,是近年来研究的重要课题之一。从分子尺度研究和揭示超分子胶体的组装过程及物理化学机制,探究胶体结构与功能的关系,是实现超分子结构和功能化的重要内容。本文基于"分子间作用的调控"及"结构与功能的关系"两个基本科学问题,系统地综述了肽基超分子胶体的组装机制、结构与功能,以及研究现状。     

生物表面活性剂胆汁盐胶束化及相行为

生物表面活性剂胆汁盐类以其在生物体内重要的生理功能及不同于传统表面活性剂独特的结构特点在众多领域引起了广泛的关注。本文对国内外关于胆汁盐类表面活性剂的胶束结构、表面吸附行为及胆汁盐在水溶液中的聚集体行为的研究成果进行了综述。同时,对胆汁盐与传统表面活性剂、双尾表面活性剂及天然脂类表面活性剂的相互作用以及聚集体的形成、胆汁盐诱导聚集体结构转变等方面的研究成果也进行了综述。     

Surface and Antimicrobial Properties of N-Palmitoyl Amino Acid–Based Surfactants

Synthesized sodium N-pamitoyl amino acids were evaluated for surface and antimicrobial properties and compared with sodium lauryl sulfate (SLS). Emulsion stability of the amino acid surfactants and calcium tolerance of the sodium N-palmitoyl isoleucine were better as compared to SLS. Wetting ability and foaming properties of the palmitic acid-based surfactants were inferior to SLS. N-Acyl amino acids exhibited better antibacterial activity compared to sodium salts of N-acyl amino acids and standard compounds against Staphylococcus aureus MLS-16 and Bacillus subtilis. These studies revealed that the palmitoyl amino acid surfactants can be exploited in household, skin care formulations, and industrial applications.     

Effects of pharmaceutical excipients on cloud points of amphiphilic drugs

The clouding behavior, i.e., formation of phase separation at elevated temperature (the temperature being known as cloud point (CP)), of three amphiphilic drugs, amitriptyline (AMT), clomipramine (CLP) and imipramine (IMP) hydrochlorides in the presence of various additives, like cationic surfactants (conventional and gemini), nonionic surfactants, bile salts, anionic hydrotropes, sodium salts of fatty acids and cyclodextrin has been investigated. These additives are generally used as drug delivery systems. The drugs used are tricyclic antidepressants. All the surfactants increase the CP of mixed micelles formed by cationic (conventional and gemini) and nonionic surfactants. Hydrotropes, bile salts and fatty acid salts, when added in low concentrations, increase the CP, whereas at high concentrations, they decrease it. β-Cyclodextrin behaves as simple sugar and decreases the CP of the drug solutions.     

Copper-metallomesogen structures obtained by ionic self-assembly (ISA): molecular electromechanical switching driven by cooperativity

In a stepwise noncovalent multiple-interaction strategy, copper(II) salts were complexed with the sodium salts of bathophenanthrolinedisulfonic acid (BPS) and bathocuproinedisulfonic acid (BCS), and organized into nanostructured materials by the addition of ammonium surfactants by means of the ionic self-assembly (ISA) route. In the case of the methyl-substituted BCS complexes, a slow color change from green to brick red was observed. UV and EPR investigations showed that the color change was due to a change in oxidation state, the resulting brick red color is typical for Cu(I) species. It is concluded that steric interactions and mechanical packing into a supramolecular structure drive this electronic transition at the metal center. When complexation is performed with double-tail ammonium surfactants, these metallomesogenic materials exhibit thermotropic liquid-crystalline phase behavior, as investigated by polarized light microscopy, differential scanning calorimetry (DSC), and temperature-dependent wide-angle and small-angle X-ray analyses. The complexity of the observed phases increased with increasing tail length of the surfactants. Complexation with double-tail C(18) surfactants yielded highly organized materials for both the BPS and BCS ligands.     

Bile acids as stationary phase in liquid chromatography

Summary Bile acids chemically bonded onto aminopropylsilica have been employed as stationary phases in liquid chromatography. Bile acid aggregates were dynamically formed around molecules chemically anchored on the supports when the eluent contained bile salts. The bile salt aggregates achieved the separation of 1,1′-binaphthyl-2,2′-diyl-hydrogenphosphate enantiomers and dansyl amino acids.     

Recent Progress in Azobenzene-Based Supramolecular Materials and Applications

Azobenzene-containing small molecules and polymers are functional photoswitchable molecules to form supramolecular nanomaterials for various applications. Recently, supramolecular nanomaterials have received enormous attention in material science because of their simple bottom-up synthesis approach, understandable mechanisms and structural features, and batch-to-batch reproducibility. Azobenzene is a light-responsive functional moiety in the molecular design of small molecules and polymers and is used to switch the photophysical properties of supramolecular nanomaterials. Herein, we review the latest literature on supramolecular nano- and micro-materials formed from azobenzene-containing small molecules and polymers through the combinatorial effect of weak molecular interactions. Different classes including complex coacervates, host-guest systems, co-assembled, and self-assembled supramolecular materials, where azobenzene is an essential moiety in small molecules, and photophysical properties are discussed. Afterward, azobenzene-containing polymers-based supramolecular photoresponsive materials formed through the host-guest approach, polymerization-induced self-assembly, and post-polymerization assembly techniques are highlighted. In addition to this, the applications of photoswitchable supramolecular materials in pH sensing, and CO₂ capture are presented. In the end, the conclusion and future perspective of azobenzene-based supramolecular materials for molecular assembly design, and applications are given.     

Self-assembly in aqueous bile salt solutions

The salts of bile acids (“bile salts”) self-assemble in aqueous solution, similar to classical amphiphiles. The micellization is not only driven by the hydrophobic effect, but also hydrogen binding. Moreover, instead of a small, hydrophilic head and a flexible, hydrophobic tail, bile salts are rigid, almost flat molecules with weakly separated hydrophobic and hydrophilic faces. This results in a complex self-assembly behaviour with very distinct aggregate properties. Some characteristics resemble the behaviour of classical amphiphiles, while others are very different and reminiscent of other classes of molecules, for example low-molecular weight gelators or chromonic materials. We review the peculiar properties of bile salt aggregates, concentrating on general trends rather than specific values and comparing them to classical amphiphiles.     

Hydrogen bonding versus van der Waals interactions: competitive influence of noncovalent interactions on 2D self-assembly at the liquid-solid interface

The structures of the self-assembled monolayers of various 4-alkoxybenzoic acids physisorbed at the liquid-solid interface were established by employing scanning tunnelling microscopy (STM). This study has been essentially undertaken to explore the competitive influence of van der Waals and hydrogen-bonding interactions on the process of two-dimensional self-assembly. These acid derivatives form hydrogen-bonded dimers as expected; however, the dimers organise themselves in the form of relatively complex lamellae. The characteristic feature of these lamellae is the presence of regular discommensurations or kinks along the lamella propagation direction. The formation of kinked lamellae is discussed in light of the registry mechanism of the alkyl chains with the underlying graphite substrate. The location of the kinks along a lamella depends on the number (odd or even) of carbon atoms in the alkyl chain. This result indicates that concerted van der Waals interactions of the alkyl chain units introduce the odd/even chain-length effect on the surface-assembled supramolecular patterns. The odd/even effects are retained even upon complexation with a hydrogen-bond acceptor. However, as the solvent is changed from 1-phenyloctane to 1-octanoic acid, the kinked lamellae as well as the odd/even effects disappear. This solvent-induced convergence of supramolecular patterns is attained by means of co-crystallisation of octanoic acid molecules in the 2D crystal lattice, which is evident from high-resolution STM images. The solvent co-adsorption phenomenon is discussed in terms of competing van der Waals and hydrogen-bonding interactions.