纳米材料的概述、制备及其结构表征

纳米材料在电子、光学、化工、陶瓷、生物和医药等诸多方面的重要应用而引起人们的高度重视。本文从以下3个方面加以论述。 一、纳米材料的概述:从分子识别、分子自组装、吸附分子与基底的相互关系、分子操作与分子器件的构筑,并通过具体的例证加以阐述,包括在STM操作下单分子反应;有机小分子在半导体表面的自指导生长;多肽-半导体表面特异性选择结合;生物分子/无机纳米组装体;光驱动多组分三维结构组装体;DNA分子机器。 二、纳米材料的若干制备方法和结构表征方法:制备方法包括:物理的蒸发冷凝法,分子束外延法(MBE),机械球磨法,扫描探针显微镜法(SPM)。化学的气相沉淀法(VCD),液相沉淀法,溶胶-凝胶法(Sol-gel),L-B膜法,自组装单分子层和表面图案化法,水热/溶剂热法,喷雾热解法,样板合成法或化学环境限制法及自组装法。 三、若干结构表征方法包括:X-射线法(XRD),扩展X射线精细结构吸收谱(EXAFS),X-射线光电子能谱(XPS),光谱法,扫描隧道显微镜/原子力显微镜(STM/AFM)和有机质谱法(OMS)。     

Future in biomolecular computation

Summary Large-scale computations for biomolecules are dominated by three levels of theory: rigorous quantum mechanical calculations for molecules with up to about 30 atoms, semi-empirical quantum mechanical calculations for systems with up to several hundred atoms, and force-field molecular dynamics studies of biomacromolecules with 10,000 atoms and more including surrounding solvent molecules. It can be anticipated that increased computational power will allow the treatment of larger systems of ever growing complexity. Due to the scaling of the computational requirements with increasing number of atoms, the force-field approaches will benefit the most from increased computational power. On the other hand, progress in methodologies such as density functional theory will enable us to treat larger systems on a fully quantum mechanical level and a combination of molecular dynamics and quantum mechanics can be envisioned. One of the greatest challenges in biomolecular computation is the protein folding problem. It is unclear at this point, if an approach with current methodologies will lead to a satisfactory answer or if unconventional, new approaches will be necessary. In any event, due to the complexity of biomolecular systems, a hierarchy of approaches will have to be established and used in order to capture the wide ranges of length-scales and time-scales involved in biological processes. In terms of hardware development, speed and power of computers will increase while the price/performance ratio will become more and more favorable. Parallelism can be anticipated to become an integral architectural feature in a range of computers. It is unclear at this point, how fast massively parallel systems will become easy enough to use so that new methodological developments can be pursued on such computers. Current trends show that distributed processing such as the combination of convenient graphics workstations and powerful general-purpose supercomputers will lead to a new style of computing in which the calculations are monitored and manipulated as they proceed. The combination of a numeric approach with artificial-intelligence approaches can be expected to open up entirely new possibilities. Ultimately, the most exciding aspect of the future in biomolecular computing will be the unexpected discoveries.     

Monitoring surface-assisted biomolecular assembly by means of evanescent-field-coupled waveguide-mode nanobiosensors

Biological self-assembly is a natural process that involves various biomolecules, and finding the missing partner in these interactions is crucial for a specific biological function. Previously, we showed that evanescent-field-coupled waveguide-mode sensor in conjunction with a SiO₂ waveguide, the surfaces which contain cylindrical nanometric holes produced by atomic bombardment, allowed us to detect efficiently the biomolecular interactions. In the present studies, we showed that the assembly of biomolecules can be monitored using the evanescent-field-coupled waveguide-mode biosensor and thus provide a methodology in monitoring assembly process in macromolecular machines while they are assembling. Evanescent-field-coupled waveguide-mode sensor Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

纤维素纳米晶的空间受限自组装: 从胶体液晶到功能材料

作为最有前途的生物衍生材料之一, 纤维素纳米晶体(CNCs)具有来源广泛、 生物相容性好和可形成光子结构等优点, 在能源、 生物医学和光子材料领域具有重要的应用价值. 本文总结了CNCs的制备、 CNCs形成的胆甾型胶体液晶及CNCs衍生的光子材料的研究进展, 重点评述了CNCs在液滴和毛细管中的自组装和基于CNCs空间受限组装的功能材料研究进展, 并讨论了空间受限CNCs自组装研究面临的挑战和未来的发展方向.     

自组装有机纳米功能材料*

大量研究发现自组装材料可以具有导电、电致发光、光－电转换等优异功能。由简单到复杂的自发组装过程无处不在, 在此基础上已经制备出了功能化染料膜、有机/无机杂化结构的组装膜、传感器、太阳能电池、光通讯元件等功能膜材料和器件。通过分子自组装形成共价键合的、具有稳定和结构可控的材料结构在生物系统中是非常重要的,如今它已日渐成为非生物学研究的焦点,有理由相信它最终将成为一门重要的技术,帮助我们制造大量复杂有用的功能材料。本文介绍了有机自组装材料的结构、自组装方法及其在应用方面取得的一些进展。     

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。     

Molecular dynamics simulations of proteins and peptides: from folding to drug design

Computer simulations of proteins, lipids and nucleic acids at equilibrium have become essentially routine. However, the fact remains that complete sampling of conformational space continues to be a bottle-neck in the field. The challenge for the future is to overcome such problems and use computational approaches to understand recognition and spontaneous self-organization in biomolecular systems (folding, aggregation and assembly of complexes), processes that cannot be directly observed experimentally. In this review, examples illustrating the extent to which simulations can be used to understand these phenomena in biomolecular systems will be presented along with examples of methodological developments to increase our physical understanding of the processes. The study cases will cover the problems of peptide-receptor recognition and the use of the information obtained for the design of new non-peptidic ligands; the study of the folding mechanism of small proteins and finally the study of the initial stages of peptide self-aggregation.     

Ordered mesoporous non-oxide materials

Ordered mesoporous inorganic non-oxide materials attract increasing interest due to their plenty of unique properties and functionalities and potential applications. Lots of achievements have been made on their synthesis and structural characterization, especially in the last five years. In this critical review, the ordered mesoporous non-oxide materials are categorized by compositions, including non-oxide ceramics, metal chalcogenides, metal nitrides, carbides and fluorides, and systematically summarized on the basis of their synthesis approaches and mechanisms, as well as properties. Two synthesis routes such as hard-templating (nanocasting) and soft-templating (surfactant assembly) routes are demonstrated. The principal issues in the nanocasting synthesis including the template composition and mesostructure, pore surface chemistry, precursor selection, processing and template removal are emphatically described. A great number of successful cases from the soft-templating method are focused on the surfactant liquid-crystal mesophases to synthesize mesostructured metal chalcogenide composites and the inorganic-block-organic copolymer self-assembly to obtain non-oxide ceramics (296 references).     

Zero-to-Two Nanoarchitectonics: Fabrication of Two-Dimensional Materials from Zero-Dimensional Fullerene

Nanoarchitectonics of two-dimensional materials from zero-dimensional fullerenes is mainly introduced in this short review. Fullerenes are simple objects with mono-elemental (carbon) composition and zero-dimensional structure. However, fullerenes and their derivatives can create various types of two-dimensional materials. The exemplified approaches demonstrated fabrications of various two-dimensional materials including size-tunable hexagonal fullerene nanosheet, two-dimensional fullerene nano-mesh, van der Waals two-dimensional fullerene solid, fullerene/ferrocene hybrid hexagonal nanosheet, fullerene/cobalt porphyrin hybrid nanosheet, two-dimensional fullerene array in the supramolecular template, two-dimensional van der Waals supramolecular framework, supramolecular fullerene liquid crystal, frustrated layered self-assembly from two-dimensional nanosheet, and hierarchical zero-to-one-to-two dimensional fullerene assembly for cell culture.     

Nanocomposites and macroscopic materials: assembly of chemically modified graphene sheets

Self-assembly of chemically modified graphenes (CMGs), including graphene oxide (GO), reduced graphene oxide (RGO) and their derivatives, has emerged as one of the most appealing strategies to develop unprecedented graphene-based functional materials. With the assistance of various non-covalent forces such as hydrogen bonding, ionic, amphiphilic and π-π interactions, CMGs decorated with multiple functional groups are favorable for assembly with different organic and inorganic components which can result in hierarchical composites possessing unique structures and functions. In this review, we will summarize the state-of-the-art self-assembly strategies that have been established to construct CMG based nanomaterials, including nanoparticles, nanospheres, nanofibers, nanorods, nanosheets, and macroscopic thin films, fibers and porous networks. The driving forces involved in the self-assembly process will be elucidated in the context. Further, we will also highlight several representative examples of applications regarding the self-assembled CMG based materials.     

Recent advances in surface plasmon resonance based techniques for bioanalysis

Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA) and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques, use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA studies, in our opinion, is very bright. Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA) and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques, use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA studies, in our opinion, is very bright.      

Elimination of aggregates of ferredoxin from its self-assembled monolayer on silicon substrate

The self-assembled ferredoxin monolayer onto the (100) surface of the silicon substrate was prepared and the nonspecifically adsorbed aggregates of ferredoxin on the substrate were successfully eliminated by using a zwitterionic surfactant, 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS). The AFM image of the self-assembled ferredoxin monolayer on the silicon substrate treated with CHAPS clearly shows that the size of ferredoxin clusters is about 20–30 nm, which is on the order of an aggregate of about five ferredoxin molecules, whereas the size of ferredoxin aggregates on the substrate without CHAPS treatment was measured to be about 100–200 nm. Those results offer a useful method for the elimination of the nonspecific adsorption of proteins onto inorganic substrates, which has been a long-term problem in the fabrication of biomolecular electronic devices by the self-assembly technique.     

几种自组装拉胀分子网络的分子模拟

报道了几种蜈蚣形、双足蜈蚣形聚合物 ,以及单箭头、双箭头形小分子通过氢键自组装形成拉胀分子网络的分子设计 .分子力学计算结果表明这些自组装分子网络靠氢键相互作用规则排列 ,具有类似倒插蜂窝网络结构 ,所设计的聚合物、小分子的合成较之以往报道的二维网络结构的合成简便易行 ,为真正分子水平意义上的拉胀结构的实现提供了新的思路和指导     

Recent advances in optical manipulation of cells and molecules for biological science

Noninvasive and nondestructive techniques for monitoring and manipulating cells or biomolecules are essential for understanding biological processes. Optical methodologies have been used for the noninvasive and nondestructive monitoring of intracellular molecules and manipulation of cellular activities to elucidate the localization and interactions of these biomolecules. Since the pioneering work of Ashkin, optical trapping has been used to study cellular elasticity and mechanical characteristics of intracellular molecules. In recent years, there has been a substantial amount of research on the optical manipulation of nanometer-sized objects, including the manipulation of the assembly of nanomaterials and the enhancement of optical forces with optical resonance effects. In the study of biomolecular manipulation by optical forces, the functions and roles of biomolecules have been clarified by analyzing the changes in cellular functions induced by manipulation. In this review, we focus on recent studies on optical trapping for the manipulation of living cells or biomolecules and introduce techniques for the manipulation of cellular functions using optical forces.     

Block copolymer based composition and morphology control in nanostructured hybrid materials for energy conversion and storage: solar cells, batteries, and fuel cells

The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices.     

共聚物的自组装研究进展

自组装是分子间通过非共价键相互作用自发组合形成的一类结构明确、稳定,同时具有某种特定功能或性能的分子聚集体或超分子结构的现象。利用共聚物自组装技术可以制备高度有序介观形貌的功能材料,这些材料有望在生物医学、药物释放、智能材料等领域得到广泛的应用。研究表明,不同结构的共聚物的自组装行为和功能一般不同,同时环境条件,如温度、pH值等也对共聚物自组装行为有很大影响。本文从共聚物结构及外部环境条件两个方面综述了近几年来共聚物的自组装行为规律,并分析了相关自组装结构应用的研究进展。     

Constructing Large 2D Lattices Out of DNA-Tiles

The predictable nature of deoxyribonucleic acid (DNA) interactions enables assembly of DNA into almost any arbitrary shape with programmable features of nanometer precision. The recent progress of DNA nanotechnology has allowed production of an even wider gamut of possible shapes with high-yield and error-free assembly processes. Most of these structures are, however, limited in size to a nanometer scale. To overcome this limitation, a plethora of studies has been carried out to form larger structures using DNA assemblies as building blocks or tiles. Therefore, DNA tiles have become one of the most widely used building blocks for engineering large, intricate structures with nanometer precision. To create even larger assemblies with highly organized patterns, scientists have developed a variety of structural design principles and assembly methods. This review first summarizes currently available DNA tile toolboxes and the basic principles of lattice formation and hierarchical self-assembly using DNA tiles. Special emphasis is given to the forces involved in the assembly process in liquid-liquid and at solid-liquid interfaces, and how to master them to reach the optimum balance between the involved interactions for successful self-assembly. In addition, we focus on the recent approaches that have shown great potential for the controlled immobilization and positioning of DNA nanostructures on different surfaces. The ability to position DNA objects in a controllable manner on technologically relevant surfaces is one step forward towards the integration of DNA-based materials into nanoelectronic and sensor devices.     

Lyotropic liquid crystal engineering-ordered nanostructured small molecule amphiphile self-assembly materials by design

Future nanoscale soft matter design will be guided to a large extent by the teachings of amphiphile (lipid or surfactant) self-assembly. Ordered nanostructured lyotropic liquid crystalline mesophases may form in select mixtures of amphiphile and solvent. To reproducibly engineer the low energy amphiphile self-assembly of materials for the future, we must first learn the design principles. In this critical review we discuss the evolution of these design rules and in particular discuss recent key findings regarding (i) what drives amphiphile self-assembly, (ii) what governs the self-assembly structures that are formed, and (iii) how can amphiphile self-assembly materials be used to enhance product formulations, including drug delivery vehicles, medical imaging contrast agents, and integral membrane protein crystallisation media. We focus upon the generation of 'dilutable' lyotropic liquid crystal phases with two- and three-dimensional geometries from amphiphilic small molecules (225 references).     

Spatiotemporal organization of coacervate microdroplets

Liquid–liquid phase separation (LLPS) has emerged as a new paradigm in the fields of soft matter, colloid chemistry, prebiotic chemistry, and cell biology. As phase separation is a dynamic assembly process, how to spatiotemporally regulate the assembly and disassembly of these micrometre-sized droplets, which are referred as biomolecular condensates in biology is essential for their diverse applications in various disciplines. Herein, we discuss recent advances in the spatiotemporal control of phase separation using different physical tools and external environmental stimuli in bulk solutions and living cells. Specifically, the exploration of phase transition in a compartmentalized protocellular system, which can bridge the gap between synthetic and intracellular LLPS systems, is summarized, and the challenges and future research directions are discussed.