基于透射电子显微镜的沸石分子筛结构研究进展

透射电子显微镜是解析沸石分子筛新结构、 分析结构缺陷和研究活性位点等的有力工具. 应用于分子筛研究的透射电子显微术总体上可以分为图像法和衍射法, 包括透射电子显微镜和扫描透射电子显微图像、 选区电子衍射和三维电子衍射, 通常结合其中的几种方法进行分析. 近年来, 随着电子显微镜硬件性能的不断提升, 特别是球差矫正器的广泛应用及各种适用于分子筛等电子束敏感材料的探测器和图像处理技术的不断革新, 在原子尺度观察分子筛的结构已成为可能. 此外, 利用原位电子显微镜技术研究分子筛的生长和催化反应机理也在逐步展开. 本文按电子显微镜方法分类, 综述了近些年基于电子显微镜的分子筛研究, 包括新结构解析、 手性确认和金属负载等的最新进展.     

现代测试技术在纳米材料研究中的应用

对电子显微技术、衍射技术、谱学技术及热分析技术的原理、特点及其在纳米材料中的应用作了评述。在此基础上指出：综合使用各种不同的分析和结构表征方法，可对纳米材料的结构和性能进行有效研究，从而指导其应用。     

一维铁磁金属纳米材料的制备、结构调控及其磁性能

一维铁磁金属纳米材料不但具有普通纳米粒子的各种特殊效应,而且具有独特的形状各向异性和磁各向异性,是构筑新型电磁功能材料的重要组元,在高密度磁记录、敏感元器件、电磁波吸收、催化剂、医学和生物功能材料等领域具有重要的应用。本文以一维铁磁金属纳米材料的制备技术为评述线索,重点论述了一维铁磁金属纳米材料的形貌参数（包括直径、长度、长径比）,晶面取向等微观结构的调控方法以及结构对磁性能的影响规律,指出发展新型的一维铁磁纳米材料的结构控制方法,研究一维材料的定向排布及组装技术,并从更深层次揭示一维结构与性能的关系以及开发一维铁磁纳米材料在各领域的实际应用是未来研究的主要发展方向。     

聚焦2011年度中国期刊基于功能纳米材料的生物传感器的研究进展

近年来,纳米材料在生物传感器领域中的应用已成为前沿性的研究方向。纳米材料具有的独特性能可将传感器的性能提高到一个全新的水平。本文分析了2011年度中国期刊报道的有关功能纳米材料在生物传感器中应用的发展状况,并根据纳米材料的类型对相应传感器在生命分析中的应用进行了分类与评述,并与国外基于功能纳米材料的生物传感器的发展趋势进行对比,以展望国内该领域的发展前景。     

无机纳米-生物界面作用的SERS研究

探索生命体对无机纳米材料的生物应答机制是高效、安全、可控地应用无机纳米材料的基础,其关键在于准确理解在生物体系中无机纳米材料与生物分子间的纳米.生物界面作用.本文主要探讨了在纳米-生物界面具有拉曼增强效应的金、银纳米材料;介绍了表面增强拉曼光谱(surface-enhanced raman spectroscopy,SERS)原位研究金、银等无机纳米材料表/界面吸附的核酸、蛋白质、磷脂等生物分子,以及细胞、病毒和细菌等与金、银纳米材料表/界面作用的研究进展;综述了SERS技术在探索纳米-生物界面作用机制、生物分子测定、生物分子界面行为监测中的应用.     

纳米材料在聚合酶链式反应体系中的应用研究进展

聚合酶链式反应(PCR)技术是现代分子生物学核心技术之一,研究提高PCR扩增效率的方法具有重要意义。传统提高PCR扩增效率的方法具有较多局限性,使得PCR扩增仍不能达到理想的效果。随着纳米技术的发展,纳米材料具有特殊的表面效应和尺寸效应,表面能进行多种修饰,易与生物大分子蛋白质、核酸等相互作用,对生物分子的结构和功能产生特别的影响。研究利用纳米材料来提高PCR扩增效率的技术和方法,具有非常重要的理论意义和应用价值。本文引用文献41篇,综述了近年来纳米材料在PCR体系中应用的现状,并展望了今后纳米材料在PCR体系中应用的发展方向及其前景。     

基于微生物体系合成无机纳米材料的研究进展

无机纳米材料在能源、生物医学等领域应用非常广泛,过去几十年间关于无机纳米材料合成方法的研究一直受到广泛关注。自然界中普遍存在的生物矿化过程赋予了生物体合成含有特殊结构和功能的无机纳米材料的能力。微生物体系合成的无机纳米材料具有环境友好、成本低廉、生物相容性好等优点,正成为纳米材料科学的一个重要研究领域。我们主要聚焦于微生物体系合成无机纳米材料的机理、影响因素、材料分类及其应用,总结了近年来关于微生物体系合成无机纳米材料的研究历程,并对该领域面临的挑战及未来的发展方向进行了展望。     

碳纳米材料的同位素标记及其在纳米毒理分析研究中的应用

碳纳米材料因独特的物理化学性质,而成为纳米产品中使用最多的纳米材料之一.这些纳米材料不可避免地通过各种途径进入环境,其生物安全性研究是碳纳米科技健康发展亟待解决的关键科学问题.寻找和建立针对环境生物体系中碳纳米材料高灵敏、本征的定量检测方法,获得与环境生物体系相关的数据,是推动其环境纳米生物效应和安全性研究的关键.在纳米毒理学研究中,同位素标记分析方法是一种不可替代的定量分析方法,尤其对碳纳米材料,具有独特的优势.结合现代分析技术,可本征、快速、准确、高灵敏地对其纳米生物效应与毒理学进行研究.本文综述了典型碳纳米材料的放射性同位素和稳定性同位素标记技术和方法、检测方法及其在碳纳米材料结构形成、生物体内定量吸收、分布、转化和排泄等纳米生物效应与毒理学分析研究的相关应用,并展望了同位素标记技术在碳纳米材料的毒理学研究和环境健康效应研究中的应用.     

低维纳米材料的理性设计:从结构预测到分子设计

低维纳米材料具有不同于体相材料的物理化学特性,是未来能源、信息与生物等技术的一个重要载体.结构预测与设计作为材料研究与发展的重要内容之一,在低维纳米材料方面的研究具有重要的意义.本文综述了近年来在低维材料理性设计方面的一些研究进展,主要基于全局结构搜索与分子设计,预测具有独特结构与性能的新型低维材料.结合第一性原理电子结构计算方法,针对特定性能开展结构搜索与设计,预测了一系列新型的光催化材料与自旋电子学材料.通过从结构预测到目标设计,可以揭示低维纳米材料中"结构"与"性能"之间的关系,寻找具有特定结构、特殊功能的新型低维纳米材料.     

原位冷冻电子断层扫描的发展及在生物研究方面的应用

对生物大分子复合物的研究和结构分析对于全面了解其功能和生物学意义至关重要. 冷冻电子显微镜在提供生物大分子结构及大分子分布等方面起到重要的作用. 近年来, 冷冻电子显微镜的硬件和软件的发展进一步提高了冷冻电子显微镜的有效性, 使其对各种生物结构、 蛋白质结构的解析更加准确快捷. 但是, 对于生物系统来说, 蛋白质和大分子复合物等均处于复杂的生理环境中, 因此原位检测生物分子的三维结构对于生物体系和结构生物学具有重要意义. 冷冻电子断层扫描作为一种功能强大的技术, 可以无需标记直接通过冷冻样品的固有衬度识别生物大分子的结构, 并且可在原位生理环境中对生物分子进行纳米级分辨率的三维成像. 本文综述了与冷冻电子断层扫描相关的样品制备和数据处理技术, 并总结了冷冻电子断层扫描技术在分离的大分子复合物和整个细胞或组织中的生物学应用.     

介电力显微术：一种观察纳米材料中电荷行为的新方法

功能纳米器件中组成材料间的电荷转移输运过程对于器件中的物理化学过程以及由此引发的器件功能会有重大影响,因此,深入理解器件工作过程中的电子／离子行为机理对于优化器件功能以及进一步开发纳米材料的应用潜力具有重要意义．传统场效应晶体管对于纳米材料的电输运测量表征反映了载流子在整个器件中的统计行为,但难以检测电荷具体的转移输运过程．同时,由于纳米材料的尺寸和分散性,基于纳米材料的场效应晶体管面临着制备困难、电极／纳米材料接触复杂和制作成本高等问题．因此,本课题组发展了介电力显微术（dielectricforcemicroscopy,DFM）方法并实现了对纳米材料电学性质的无接触、高空间分辨率和快速表征．本文介绍了介电力显微术的基本原理,列举了其在探究一维纳米材料、纳米颗粒以及有机半导体薄膜电学性质上的一些应用实例．这些实例验证了介电力显微术对纳米材料电学性质的表征能力,并展现了这一技术在纳米材料物理化学性质和纳米器件功能研究上的广阔前景．     

Characterization of nanomaterials in food by electron microscopy

Engineered nanomaterials (ENMs) are increasingly being used in the food industry. In order to assess the efficacy and the risks of these materials, it is essential to have access to methods that not only detect the nanomaterials, but also provide information on the characteristics of the materials (e.g., size and shape).This review presents an overview of electron microscopy (EM)-based methods that have been, or have the potential to be, applied to imaging ENMs in foodstuffs. We provide an overview of approaches to sample preparation, including drying, chemical treatment, fixation and cryogenic methods. We then describe standard and non-standard EM-based approaches that are available for imaging prepared samples. Finally, we present a strategy for selecting the most appropriate method for a particular foodstuff.     

Three‐Dimensional Characterization of Noble‐Metal Nanoparticles and their Assemblies by Electron Tomography

New developments in the field of nanomaterials drive the need for quantitative characterization techniques that yield information down to the atomic scale. In this Review, we focus on the three‐dimensional investigations of metal nanoparticles and their assemblies by electron tomography. This technique has become a versatile tool to understand the connection between the properties and structure or composition of nanomaterials. The different steps of an electron tomography experiment are discussed and we show how quantitative three‐dimensional information can be obtained even at the atomic scale.     

Fluorescence microscopy-based analysis of apoptosis induced by platinum nanoparticles against breast cancer cells

In recent years, capping molecules onto the surface of nanomaterials has become an interesting field of research. This idea facilitates the biological applications of nanomaterials with a modified surface. Keeping this in mind, the present study addresses the development of polymeric platinum nanoparticles using polyvinyl pyrrolidone (PVP). High-throughput characterization indicates that polymeric platinum nanoparticles have an excellent surface morphology and good dispersity in aqueous solution. More specifically, high resolution-transmission electron microscopy studies showed that the polymeric platinum nanoparticles were spherical and measured 2–10 nm. Furthermore, the polymeric platinum nanoparticles were evaluated for anticancer properties against human MCF-7 breast cancer cell lines. The results show that polymeric platinum nanoparticles inhibited the growth of cancer cells in a dose-dependent manner with a half-maximum inhibitory concentration of 96.36 μg ml⁻¹. In addition, fluorescence-based staining methods confirmed an inquest in the pattern of cell death inferring late apoptotic bodies, nuclear fragmentation, mitochondrial membrane potential and generation of reactive oxygen species. The overall findings suggest that the polymeric platinum nanoparticles confer anticancer activity and may be suitable chemotherapeutic agents in the future. Finally, the results from this study can be extended to other types of cancer as well.     

Customized Bio‐functionalization of Nanocomposite Carbon Paste Electrodes for Electrochemical Sensing: A Mini Review

Over the past few decades, the (bio)functionalization of carbon nanomaterials (CNMs), such as nanohorns, carbon nanotubes, graphene, graphite and related with a wide range of (bio)modifiers have been extensively studied for their incorporation on different pure metal or carbon electrode surfaces via drop‐casting. However, CNMs are also shown to be important functional additives for polymers, having great potential to produce rigid nanocomposite materials with a range of enhanced properties, including mechanical, optical, electrical, thermal and electrochemical. The high malleability derived from the host polymer allows alternative strategies that can be carried out in order to incorporate different types of (bio)modifiers in/on/into a polymeric nanocomposite electrode. Accordingly, this mini review overviews the main methodologies used for the bio‐functionalization of electrochemical transducers based on nanocomposite carbon paste electrodes (NC‐CPEs). Additionally, the most extensively (bio)modifiers used in electrochemical (bio)sensing, together with their various electrocatalytical performance are also discussed, fact that might serve as a general outlook for planning further research.     

The art of two-dimensional soft nanomaterials

The discovery of graphene has triggered the explosive development of two-dimensional(2D) nanomaterials, including both inorganic and organic species. Benefiting from the simple elemental composition, inorganic 2D nanomaterials were the center research in the past decade, which has long shadowed the research of 2D organic(or soft) nanomaterials. Although many kinds of2D soft nanomaterials have been successfully prepared, a unified definition for them is still impossible due to the complicate and quite different chemical structures between each other and even relying on totally different techniques to distinguish them. Since our first review on 2D soft nanomaterials in 2015, this field has moved forward with big success. In this review, we will focus on the development of 2D soft nanomaterials after 2015. In order to deliver better overview of this field, new and comprehensive classification is used in this review: 2D aromatic molecules, graphene and graphene nanoribbons, graphyne and graphdiyne,BxCyNznanosheets, 2D polymers, 2D supramolecules, crystalline 2D assemblies, 2D covalent organic frameworks, 2D metalorganic frameworks, sandwich-like 2D porous polymers, 2D polymer nanosheets, etc. The focus of this review lies on synthetic strategies and the challenges of characterization, definition and fundamental understanding.     

Dielectrophoretic placement of quasi-zero-, one-, and two-dimensional nanomaterials into nanogap for electrical characterizations

DEP is one of promising techniques for positioning nanomaterials into the desirable location for nanoelectronic applications. In contrast, the lithography technique is commonly used to make ultra-thin conducting wires and narrow gaps but, due to the limit of patterning resolution, it is not feasible to make electrical contacts on ultra-small nanomaterials for a bottom-up device fabrication. Thus, integrating the lithography and dielectrophoresis, a real bottom-up fabrication can be achieved. In this work, the device with the nanogap in between two nanofinger-electrodes is made using electron-beam lithography from top down and the ultra-small nanomaterials, such as colloidal PbSe quantum dots, polyaniline nanofibers, and reduced-graphene-oxide flakes, are placed in the nanogap by DEP from bottom up. The threshold electric field for the DEP placement of PbSe nanocrystals was roughly estimated to be about 8.3 × 10(4) V/cm under our experimental configuration. After the DEP process, several procedures for reducing contact resistances are attempted and measurements of intrinsic electron transport in versatile nanomaterials are performed. It is experimentally confirmed that electron transport in both PbSe nanocrystal arrays and polyaniline nanofibers agrees well with Prof. Ping Sheng's model of granular metallic conduction. In addition, electron transport in reduced-graphene-oxide flakes follows Mott's 2D variable-range-hopping model. This study illustrates an integration of the electron-beam lithography and the DEP techniques for a precise manipulation of nanomaterials into electronic circuits for characterization of intrinsic properties.     

Advances in DNA Origami Nanopores: Fabrication,Characterization and Applications

In recent years, bio‐nanopore and solid‐state nanopore have been greatly improved for molecule bio‐sensing. Whereas, the development of this scientific field seems to have encountered a bottleneck due to their respective limitations. The small pore size of the former impedes the detection of large single molecule, and the latter is difficult to achieve similar accuracy and functional control. DNA origami plays a novel role to bring more opportunities for the development of nanopore technology since it is relatively easy to synthesize and modify. This review mainly focuses on introducing the DNA origami nanopore fabrication methods, characterization and application. Meanwhile, the challenges in the present DNA origami nanopore research are also discussed.     

Signal amplification using functional nanomaterials for biosensing

Signal amplification based on biofunctional nanomaterials has recently attracted considerable attention due to the need for ultrasensitive bioassays and the trend towards miniaturized assays. The biofunctional nanomaterials can not only produce a synergic effect among catalytic activity, conductivity and biocompatibility to accelerate the signal transduction, but also provide amplified recognition events by high loading of signal tags, leading to a highly sensitive and specific biosensing. Most importantly, nanoscaled materials are in direct contact with the environment, which permits them to act as chemical and biological sensors in single-molecule detection of biomolecules. In this tutorial review, we will focus on recent significant advances in signal amplification strategies combining the cross-disciplines of chemistry, biology, and materials science, and highlight some elegant applications of biofunctional nanomaterials as excellent electronic or optical signal tags in ultrasensitive bioanalysis. The biofunctional nanomaterials-based biosensing opens a series of concepts for basic research and offers new tools for detection of trace amounts of a wide variety of analytes in clinical, environmental, and industrial applications.     

双金属纳米材料与催化

双金属纳米材料作为工业上少见的一类催化剂材料,在合成过程中可通过对其组成、结构晶粒大小尺寸的调控,实现其催化性能的合理调控,因此,近年来备受催化材料化学领域科技工作者的广泛关注.随着纳米材料调控合成方面的技术进步,具有均一小尺寸可控结构的纳米材料对于制备高效催化剂材料和研究催化反应机理具有重要的意义.结合纳米技术探索开发设计新型的双金属纳米催化剂材料颇具挑战性.本文围绕双金属纳米催化剂的合成、结构及其相关催化性能,从不同的双金属纳米催化剂出发,对催化剂的性能提高、催化机理研究的若干问题和分析手段及方法在催化研究中的进展发表一点初浅认识.