原子团簇

原子团簇与无机纳米材料一样,可以看作是纳米尺度的无机物质形态,但是具有确定的结构和组成,因此可以成为认识和研究纳米乃至大块固体表面结构的分子模型。由原子团簇组装的材料,有可能兼具纳米材料和分子材料的特性。     

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。     

大孔道介孔氧化硅/碳基纳米材料的设计合成与应用

由于具有较大的孔道尺寸、 丰富的化学组成以及广阔的应用前景, 大孔道介孔纳米材料近年来引起了科研工作者的广泛关注. 分别利用复合胶束和无机纳米晶作为结构基元进行可控自组装的软模板法和硬模板法是合成这类大孔道介孔纳米材料最有效的两类方法. 本文总结了一系列基于不同类型软模板或硬模板共组装形成大孔道介孔纳米材料的合成方法和策略, 并讨论了所获得的大孔道介孔纳米材料在催化、 能量转换与存储以及生物医学中的应用. 最后, 对利用新型嵌段聚合物或复杂结构纳米晶合成大孔道介孔纳米材料的前景和挑战进行了展望.     

电荷驱动水中氧化物纳米颗粒自组装的原位透射电子显微镜研究

<正>由于氧化物纳米材料具有较大的比表面积和表面活性,因此被广泛地应用于催化、能源储存、纳米器件等各种领域。人们通过各种不同的合成技术手段,实现对氧化物纳米材料表面形貌进行调控,进而获得具有优异性能的纳米材料。在各种纳米材料合成手段中,可控性自组装技术是一种有效调控纳米材料尺寸及形貌特征的方法,在纳米材料的合成以及制备方面具有较大的应用潜力1。纳米颗粒的自组装过程及其自组装的结构形态特征,常常受到纳米颗粒之间的范德华力、氢键、静电力、疏水性、偶极矩等相互作用的影响2–5。     

手性模板合成CdS纳米棒

由于纳米材料具有量子尺寸效应及大的比表面积等性质而使其在电子学[1]、光学[2]、催化[3]和陶瓷[4]等领域显示出诱人的应用前景. 近年来纳米材料的制备及纳米技术发展迅速, 特别是具有特殊光电活性的新型无机纳米材料的制备已引起人们的普遍关注. 现在合成纳米材料的方法主要包括反相胶束法[5]、 LB膜法[6]、嵌段共聚物法[7]和模板合成法[8]. 其中模板合成技术不仅可以通过设计新型的模板分子, 还可通过模板分子的不同自组装行为来调控纳米材料的尺寸和形貌. Stupp等[9]曾利用溶致液晶的六方中间相作为模板, 在其纳米孔隙中成功地合成了具有六方排列超晶格纳米结构的材料. 本文以双亲性丙氨酸衍生物为模板, 在不同的化学微环境下合成了结构不同的CdS纳米棒.     

纳米材料的自组装研究进展

本文主要评述了近年来纳米材料自组装的研究进展，即对以纳米材料(包括零维的纳米粒子和一维的纳米管/线)为单元而开展的自组装方面的工作进行了介绍。将纳米材料自组装为各种尺度的有序结构会产生更优异的整体的协同性质，这对于以纳米材料为基础而构筑的微纳米器件有着重要的意义。由于目前纳米材料的研究主要集中在零维和一维体系，因此，本文分别就此两种体系的自组装行为进行了评述。具体内容包括：单分子层薄膜修饰的无机纳米粒子的自组装、大分子修饰的无机纳米粒子的自组装、未被修饰的无机纳米粒子的自组装；表面张力及毛细管力诱导的一维纳米材料的自组装、模板诱导的一维纳米材料的自组装、静电力诱导的一维纳米材料的自组装。     

纳米晶核的尺寸与表面对生长与组装过程影响的研究进展

晶核作为晶体生长过程中新相形成的开始,理解它们的性质和行为特点对纳米材料的控制合成有重要指导意义,尤其对形貌和尺寸的调控。可控合成的超小尺寸纳米晶(<5 nm)为研究晶核的性质提供了一个理想模型。本文基于纳米晶核在纳米材料控制合成中的研究进展,论述了晶核的尺寸与表面结构对纳米材料生长与组装模式的影响,尤其是基于纳米晶核预组装途径的晶体生长模式。     

嵌段共聚物反介观液晶相新方法合成多级有序排列的二氧化硅纳米棒

在非极性溶剂体系中,开辟了利用反相液晶法制备多级有序纳米材料的新方法.利用嵌段共聚物表面活性剂在非极性溶剂中形成反相胶束,无机硅物种可以进入胶束的内部,在溶剂挥发后,有机-无机物种进一步组装成为反相六方液晶相.除去模板剂后即制备出尺寸规则的二氧化硅纳米棒材料.由于嵌段高分子的作用,六方排列的二氧化硅纳米棒进一步排列成层状结构(层间距约150nm).通过选择表面活性剂及改变其浓度,纳米棒的尺寸可以在9～15nm范围内调变.该反应途径对于合成其它尺寸均一、多级有序排列的纳米棒材料是非常有意义的.     

无机纳米材料的光化学合成

无机纳米材料的合成是纳米科学发展的前提和基础之一。区别于传统的高温湿化学合成法,光化学方法在无机纳米材料的合成中表现出许多优点,并在近年来受到了广泛关注。本文分三个部分综述了近年来光化学方法在无机纳米材料合成中的应用,具体包括贵金属纳米材料的光化学合成与负载,半导体纳米材料的光化学合成以及表面等离子体共振诱导的各向异性金属纳米晶合成。最后,在总结光化学方法在无机纳米材料合成中体现出的优势及目前研究仍存在不足的基础上,我们对其未来可能的发展方向进行了展望。     

离子液体在无机纳米材料合成上的应用

室温离子液体作为一种新型的绿色环保溶剂,在无机纳米材料合成中的应用引起越来越多研究者的注意。目前,已经利用室温离子液体合成出了纳米多孔材料、纳米粒子和中空球、一维纳米材料等。与传统的溶剂相比,离子液体在合成过程中体现出了很多优势,且合成的产物也不同,为无机纳米材料的合成开辟了一条新途径。本文就近年来国内外相关研究进展,对离子液体在无机纳米材料合成中的应用进行综述。     

Structure of peptides on metal oxide surfaces probed by NMR

Peptides that bind inorganic surfaces and template the formation of nanometer-sized inorganic particles are of great interest for the self- or directed assembly of nanomaterials for sensors and diagnostic applications. These surface-recognizing peptides can be identified from combinatorial phage-display peptide libraries, but little experimental information is available for understanding the relationship between the peptide sequence, structure at the nanoparticle surface, and function. We have developed NMR methods to determine the structures of peptides bound to inorganic nanoparticles and report on the structure of three peptides bound to silica and titania surfaces. Samples were prepared under conditions leading to rapid peptide exchange at the surface such that solution-based nuclear Overhauser experiments can be used to determine the three-dimensional structure of the bound peptide. The binding motif is defined by a compact "C"-shaped structure for the first six amino acids in the 12-mer. The orientation of the peptide on the nanoparticle surface was determined by magnetization transfer from the nanoparticle surface to the nearby peptide protons. These methods can be applied to a wide variety of abiotic interfaces to provide an insight into the relationship between the primary sequence of peptides and their functionality at the interface.     

Interplay between amphiphilic peptides and nanoparticles for selective membrane destabilization and antimicrobial effects

As a result of an increasing number of bacteria developing resistance against antibiotics, antimicrobial peptides (AMPs) are attracting significant interest, particularly in relation to identification of peptides displaying potent but selective effects. Much less focus has been placed on delivery systems for AMPs, despite AMPs suffering from delivery challenges related to their size, cationicity, and amphiphilicity. Inorganic nanoparticles may provide opportunities for controlling peptide release, reducing infection-related AMP degradation, or increasing bioavailability. Numerous such nanomaterials display potent and triggerable antimicrobial effects on their own. When combined with AMPs, combinatorial and synergistic effects in relation to the behavior of such mixed systems as antimicrobials have been observed. The mechanistic origin of these effects are poorly understood that at present, however, precluding rational design of mixed nanoparticle antimicrobials/AMPs and nanoparticulate delivery systems for AMPs. Here, the area of membrane interactions and antimicrobial effects of inorganic nanomaterials are briefly outlined, in combination with AMPs.     

Janus纳米材料的制备及结构调控

用3-(甲基丙烯酰氧)丙基三甲氧基硅烷(MPS)、 氨丙基三乙氧硅烷(APTES)和正硅酸乙酯(TEOS)溶胀聚苯乙烯中空微球的壳层, 在壳层表面通过溶胶-凝胶过程, 使亲油和亲水基团通过自组装作用分别朝向聚苯乙烯基体和水相, 形成Janus结构. 用良溶剂N,N-二甲基甲酰胺(DMF)溶解除去聚苯乙烯, 得到二氧化硅基复合Janus纳米材料. 改变反应体系pH值和单体用量等可以调控Janus纳米材料微结构, 得到Janus中空球和纳米片.     

Current progresses and trends in carbon nanomaterials-based electrochemical and electrochemiluminescence biosensors

The enormous potential of biosensors in medical diagnostics has motivated scientists to develop newer innovative tools and advance biosensing technologies. The use of cell, organelles, nucleotides, aptamers, antibodies, affibodies, proteins, peptides, molecules, and printed polymers, merged with nanotechnology, offers excellent tools to prepare highly sensitive and advanced biosensors. Therefore, the current decade has witnessed a rapid surge in the fabrication of different nanomaterial-based biosensors. Among them, carbon nanomaterials (CNMs) have emerged highly attractive in the fabrication of both electrochemical and electrochemiluminescence (ECL) biosensors. On one hand, CNMs bear prominent electrical conductivity, large surface area to immobilize adequate amount of biomolecules, an enhanced loading capacity, improved biocompatibility, and active site for electrochemical reaction. Additionally, CNMs could be chemically modified for the covalent coupling with the biomolecules. On the other hand, both electrochemical and ECL biosensors allow for cost-effective, rapid, and real-time detection with excellent sensitivity and selectivity, with the capability of integrating different biomolecules and CNMs on the same chip. However, currently there is not a single review, which includes CNM-based electrochemical and ECL biosensors' current progress and trends. Therefore, this review intends to survey the current progress and future trends in CNM-based electrochemical and ECL biosensors.     

Micro-extraction of Xenobiotics and Biomolecules from Different Matrices on Nanostructures

Sample preparation is the backbone of any analytical procedure; it involves extraction and pre-concentration of the desired analytes; often at trace levels. The present article describes the applications of nanomaterials (carbon-based inorganic and polymeric materials) in miniaturized extraction such as solid phase micro-extraction, stir-bar sorptive extraction, liquid phase micro-extraction, and dispersive liquid phase micro-extraction in the analyses of aqueous samples. The nanoparticles used for micro-extractions are discussed on the basis of their chemical natures. The synthetic route and the preparation of nanomaterials are described along with the optimization strategies for micro-extraction. A comparison between the conventional materials and nanomaterials for micro-extraction is proposed. The key roles of the nanomaterials for the micro-extraction of different analytes such as drugs, pesticides, polycyclic aromatic hydrocarbons, proteins and peptides from aqueous samples are reported. The use of nanomaterials, combined with miniaturized micro-extraction techniques, proved to be highly promising for sample preparation of various matrices with analytes at trace levels.     

Optimizing Dispersion,Exfoliation, Synthesis,and Device Fabrication of Inorganic Nanomaterials Using Hansen Solubility Parameters

Hansen solubility parameters (HSPs) were established by Hansen in 1967 and predict miscibility between different material systems. So far, HSP theory works across polymers, crystalline bulk solids and nanomaterials and can be used to identify single solvents or, more likely, blends of solvents that deliver not only the initial solubility but also control it during reaction processes. This minireview summarizes the recent progress on HSP theory to optimize dispersion, exfoliation, synthesis, and device fabrication of inorganic nanomaterials. First, we briefly introduce HSP theory and determination of HSPs. Then, we discuss in detail the utilization of HSPs for inorganic nanomaterials, focusing on carbon nanomaterials, two-dimensional non-graphene nanomaterials, and metal oxide nanoparticles. Finally, challenges and perspectives of HSP theory in inorganic nanomaterials are reviewed.     

Control of Chiral Nanostructures by Self‐Assembly of Designed Amphiphilic Peptides and Silica Biomineralization

Peptides, the fundamental building units of biological systems, are chiral in molecular scale as well as in spatial conformation. Shells are exquisite examples of well‐defined chiral structures produced by natural biomineralization. However, the fundamental mechanism of chirality expressed in biological organisms remains unclear. Here, we present a system that mimics natural biomineralization and produces enantiopure chiral inorganic materials with controllable helicity. By tuning the hydrophilicity of the amphiphilic peptides, the chiral morphologies and mesostructures can be changed. With decreasing hydrophilicity of the amphiphilic peptides, we observed that the nanostructures changed from twisted nanofibers with a hexagonal mesostructure to twisted nanoribbons with a lamellar mesostructure, and the extent of the helicity decreased. Defining the mechanism of chiral inorganic materials formed from peptides by noncovalent interactions can improve strategies toward the bottom‐up synthesis of nanomaterials as well as in the field of bioengineering.     

Isolation of ZnO-binding 12-mer peptides and determination of their binding epitopes by NMR spectroscopy

Inorganic-binding peptides are in the focus of research fields such as materials science, nanotechnology, and biotechnology. Applications concern surface functionalization by the specific coupling to inorganic target substrates, the binding of soluble molecules for sensing applications, or biomineralization approaches for the controlled formation of inorganic materials. The specific molecular recognition of inorganic surfaces by peptides is of major importance for such applications. Zinc oxide (ZnO) is an important semiconductor material which is applied in various devices. In this study the molecular fundamentals for a ZnO-binding epitope was determined. 12-mer peptides, which specifically bind to the zinc- or/and the oxygen-terminated sides of single-crystalline ZnO (0001) and (000-1) substrates, were selected from a random peptide library using the phage display technique. For two ZnO-binding peptides the mandatory amino acid residues, which are of crucial importance for the specific binding were determined with a label-free nuclear magnetic resonance (NMR) approach. NMR spectroscopy allows the identification of pH dependent interaction sites on the atomic level of 12-mer peptides and ZnO nanoparticles. Here, ionic and polar interaction forces were determined. For the oxygen-terminated side the consensus peptide-binding sequence (HSXXH) was predicted in silico and confirmed by the NMR approach.     

纳米材料在肿瘤光动力治疗中的研究进展

光动力治疗是新兴的非侵入性癌症治疗方法。纳米材料以其独特的结构以及光物理、光化学性质成为可用于光动力治疗的光敏剂。根据纳米材料的不同种类,分别对无机非金属纳米材料、无机金属纳米材料、有机小分子纳米材料以及有机聚合物纳米材料等的构建策略及其在光动力治疗肿瘤中的应用进行综述。展望了纳米材料在未来肿瘤光动力治疗中的挑战和发展方向。为新一代纳米光敏剂的构建提供创新思路,并扩展其在癌症治疗中的潜力。