非共价键法改性碳纳米管的研究进展

阐述了非共价键改性在碳纳米管功能化方面的应用进展,详细介绍了表面活性剂修饰、小分子的π-π堆积相互作用、聚合物的缠绕和包覆、生物大分子的包裹和吸附、内嵌填充修饰等改性方式的研究现状,并提出了非共价键法修饰碳纳米管未来改进的方向,探讨了不同修饰物与碳纳米管之间的相互作用机制。其中,含有共轭基团或芳基基团的聚合物,可以通过其共轭或芳基基团与碳纳米管间的π-π相互作用和范德华作用,实现对碳纳米管的非共价物理包覆。经聚合物功能化的碳纳米管在电池、催化剂、生物传感器和电化学装置上有较好的应用前景。此外,生物大分子对碳纳米管的非共价修饰不仅可以改善其在生物体系中的水溶性,而且通过合理设计还可以避免蛋白质、核酸等生物分子的非特异性吸附,从而得到具有特异性的生物分子-碳纳米管复合体系。     

量子点在电化学生物传感研究中的应用*

量子点( Quantum dots,QDs )由于具有独特的光学、电化学和电致化学发光特性已受到广泛地重视,而利用量子点构建电化学生物传感器则是量子点最有前途的应用领域之一。量子点具有的高比表面积、高表面活性及小尺寸等特性使它对外界的光、电、温度等十分地敏感,外界环境的微小改变就会迅速引起其表面或界面粒子价态和电子转移行为的显著变化,基于生物大分子引起的QDs表面电化学行为变化而构建的电化学生物传感器,其特点是响应灵敏高、速度快且选择性优良。本文对量子点的光学、电化学和电致化学发光特性作了简单介绍,并重点回顾了其在电致化学发光、免疫分析、DNA杂交、蛋白质检测、农药检测和糖类检测电化学生物传感研究中的应用。同时,对量子点在电化学生物传感研究中的应用前景及研究方向进行了评述和展望。     

纳米结构聚吡咯构建的生物传感器

本文总结了纳米结构聚吡咯对生物分子的固定方法如吸附法、电化学聚合包埋法、共价键偶联法以及分子印迹法,重点评述了基于纳米结构聚吡咯的电流型生物传感器,如酶、核酸、免疫传感器等的工作原理和探测性能.指出聚吡咯纳米敏感材料优良的选择透过性和高比表面积有利于生物分子的固定,提高了生物传感器的敏感度;聚吡咯良好的生物相容性和抗干扰性,可以很好地保持生物分子的活性,提高生物传感器的选择性和环境稳定性;聚吡咯与其它敏感材料如碳纳米管或金属纳米粒子复合,两者的协同效应使电极的电化学信号放大、电催化活性可提高2～4个数量级.检出限最高可提升5万倍;聚吡咯纳米生物传感器在生物医学工程、临床诊断、环境监测、食品卫生和科学等领域展现出广阔的应用前景.     

纳米材料应用于无酶电化学生物传感器的研究进展

无酶电化学生物传感器具有环境适用性强、稳定性高、材料简单易得、灵敏度高、检测限低等特点，近年来受到研究者广泛关注。纳米材料有类酶活性，表现出类似天然酶的酶促反应动力学和催化机理，且能够增强界面吸附性能，增加电催化活性，并促进电子转移动力学，从而广泛应用于无酶电化学生物传感器。本文探索了具有电催化活性的纳米材料及其修饰电极的制备方法，介绍了无酶电化学传感器在医疗诊断、食品检测、环境检测以及其他领域中的应用，讨论了开发基于纳米材料的电化学传感器的未来机遇和挑战。     

生物大分子印迹传感器研究进展

分子印迹传感器在有机小分子分析检测方面的应用已趋近成熟,在生物大分子检测方面的应用近年来也逐渐增多.本文就近年来分子印迹技术在大分子生物传感器中的构建及应用进行综述,包括光学传感器、电化学传感器、质量型传感器等,并对目前分子印迹传感器在生物大分子检测方面存在的问题进行分析,对生物大分子印迹传感器的未来发展方向提出展望.     

卟啉-碳纳米管复合物研究进展

碳纳米管是具有一维纳米结构的新型纳米材料,具有许多独特的物理、化学性质.卟啉对可见光具有强烈吸收,其大π共轭体系使其具有良好的电子给予能力,可作为人工光合作用体系的光捕捉单元.将具有电子接受能力的碳纳米管与卟啉结合起来,通过卟啉对碳纳米管进行共价和非共价修饰,可以改善碳纳米管在溶剂中的溶解分散性能,同时实现卟啉和碳纳米管之间有效的电子传递,形成具有独特光电和光学性质卟啉-碳纳米管复合物.该类物质具备良好的应用前景,是碳纳米管和卟啉研究中的热点.就近年来该类复合物的构筑方法及性质研究等方面的进展进行了综述.     

小分子与生物大分子间非共价相互作用分析方法研究进展

对小分子与生物大分子间非共价相互作用分析方法的研究进展作了较详细的评述。重点介绍了光谱、电化学、核磁共振、质谱等方法在小分子与生物大分子间相互作用研究中的应用及进展,总结了这些分析方法的优缺点,引用文献56篇。     

电化学方法在荧光碳点研究中的应用

作为以碳为骨架结构的新型纳米材料,碳点具有许多优良的性能,如发射波长可调、良好的光稳定性、抗光漂白、良好的水溶性以及易于生物偶联等. 正是因为这些优点,碳点和其它碳质纳米材料（富勒烯、碳纳米管、石墨烯）一样受到了广泛的关注. 电化学方法制备碳点具有条件温和、费用低廉、后处理简单等特点. 另外,电化学方法在材料的表面结构分析以及发光机理的研究中也有其独特的优势. 本文即就电化学方法在荧光碳点的制备以及发光机理探讨中的应用作了综述,并简略介绍了碳点在传感器中的应用,提出了优化电化学方法制备碳点的某些设想.     

基于共价有机框架的电化学生物传感器在生物样品检测中的应用

共价有机框架材料(Covalent Organic Frameworks, COFs)是一种具有纳米级结构有序性的二维或三维有机结晶材料, 具有高度周期性和可修饰性等结构优点. 基于COFs制备的电化学生物传感器具有灵敏度高、特异性强、重复性好等特点, 在检测生物样品方面具有广阔前景. 本综述简要概述了COFs的合成方法与策略、电化学生物传感器的介绍与分类以及COFs在电化学生物传感检测生物样品领域的应用. 最后本综述对COFs材料在生物传感领域的技术瓶颈与未来的发展方向进行了总结与讨论.     

碳纳米管气体传感器研究进展

碳纳米管具有一维纳米结构、高表面吸附能力、良好的导电性和电子弹道传输特性等优异的力学、电学、物理和化学性能,成为制作纳米气体传感器的理想材料之一.近年来,各国研究者广泛开展了碳纳米管气体传感器的研究工作,并取得了许多显著成果.研究结果表明,碳纳米管气体传感器具有灵敏度高、响应速度快、尺寸小、能耗低和室温下工作等诸多特点.本文结合本研究小组近年来在碳纳米管气体传感器领域所做的大量研究工作,从环境监测、医学检测和国防军事等方面,对碳纳米管气体传感器取得的研究进展进行了综述,同时也阐述和分析了碳纳米管气体传感器的工作原理和制作过程.尽管面临诸多挑战,随着研究的不断深入,碳纳米管气体传感器仍有可能凭借其独特的性能优势成为当前商业应用气体传感器的有力竞争者.     

Functionalized carbon nanotubes and nanofibers for biosensing applications

This review summarizes recent advances in electrochemical biosensors based on carbon nanotubes (CNTs) and carbon nanofibers (CNFs) with an emphasis on applications of CNTs. CNTs and CNFs have unique electric, electrocatalytic and mechanical properties, which make them efficient materials for developing electrochemical biosensors.We discuss functionalizing CNTs for biosensors. We review electrochemical biosensors based on CNTs and their various applications (e.g., measurement of small biological molecules and environmental pollutants, detection of DNA, and immunosensing of disease biomarkers). Moreover, we outline the development of electrochemical biosensors based on CNFs and their applications. Finally, we discuss some future applications of CNTs.     

Applications of Carbon Nanotubes in Electrochemical DNA Biosensors

The discovery of carbon nanotubes (CNTs) about a decade ago has brought fascinating evolutions in electronics, material industry, as well as bio-techniques for DNA analysis, gene therapy, drug delivery etc. It has also dramatically promoted the development of DNA biosensing techniques, especially electrochemical DNA biosensor. The application of CNTs in electrochemical DNA biosensors includes two main aspects: on one hand, using CNTs as a novel substrate not only enables immobilization of DNA molecules but also serves as a powerful amplifier to amplify signal transduction event of DNA hybridization. On the other hand, CNTs can also be employed as a powerful carrier to pre-concentrate enzymes or electroactive molecules for electrochemical sensing of DNA hybridization as a novel indicator. In this review, we place emphasis on recent studies of CNTs-based electrochemical DNA biosensors based on these two aspects, with advantages and disadvantages of each aspect introduced herein.     

Carbon nanotubes for electrochemical biosensing

The aim of this review is to summarize the most relevant contributions in the development of electrochemical (bio)sensors based on carbon nanotubes in the last years.Since the first application of carbon nanotubes in the preparation of an electrochemical sensor, an increasing number of publications involving carbon nanotubes-based sensors have been reported, demonstrating that the particular structure of carbon nanotubes and their unique properties make them a very attractive material for the design of electrochemical biosensors.The advantages of carbon nanotubes to promote different electron transfer reactions, in special those related to biomolecules; the different strategies for constructing carbon nanotubes-based electrochemical sensors, their analytical performance and future prospects are discussed in this article.     

A Review on the Effects of Introducing CNTs in the Modification Process of Electrochemical Sensors

This review summarizes some developments in the fabrication of modified sensors and biosensors through the incorporating the carbon nanotubes (CNTs) in their modification ingredients. A large number of papers have paid attention towards the application of carbon nanotubes (CNTs) as electrode constituents and studied its electrochemical behavior. Here, we survey the achievements in the detection of various substances with high selectivity and sensitivity provided using CNTs based electrodes. Moreover, modified electrodes by CNTs have demonstrated the electrocatalytic features and higher sensitivity in detection of analytes. The improved characteristics arises from the large surface area and good conductivity of CNTs. However, it should be considered that the use of single walled carbon nanotubes (SWCNTs) or multi‐walled carbon nanotubes (MWCNTs), the presence of impurities, and the chemical procedures adopted are effective on the performance of the modified sensors.     

Immobilization of Acetylcholinesterase onto Carbon Nanotubes Utilizing Streptavidin-biotin Interaction for the Construction of Amperometric Biosensors for Pesticides

Abstract

Carbon nanotubes (CNTs) are very promising materials onto which bioactive molecules can be immobilized in the construction of biosensors. Streptavidin was used as a molecular linker to immobilize biotinylated acetylcholinesterase (AChE) on CNTs in a gentle and controllable fashion for pesticide biosensors. Glassy carbon electrodes coated with the CNT-enzyme complex had high affinity for the substrate acetylthiocholine and produced strong peak oxidation currents in electrochemical assays. We also propose a new method, i.e., the use of relative net slope rather than the percentage of inhibition, in the calculation of pesticide concentrations. The biosensors could detect low levels of the pesticide methyl paraoxon.     

Electrochemistry of polystyrene intercalated vertically aligned single- and double-walled carbon nanotubes on gold electrodes

Electrochemical electrodes incorporating double- and single-walled carbon nanotubes (CNTs) were fabricated on cysteamine modified flat gold substrates. Through covalent coupling of the amine end groups with carboxyl functionalized CNTs, a dense forest of vertically aligned CNTs was produced. To these a 30 nm thick insulating polystyrene layer was spin coated, resulting in exposure of the uppermost carbon nanotube ends. The electrochemical performance of each electrode was then determined using the redox probe ruthenium hexaamine. Once surrounded by polymer, the double-walled CNTs (DWCNTs) showed an improved electron transfer rate, compared to the single-walled electrode. This improvement was attributed to the protection of the electronic properties of the inner wall of the DWCNT during the chemical modification and suggests that DWCNTs may offer a useful alternative to SWCNTs in future electrochemical sensors and biosensors.     

Carbon‐Nanotube Based Electrochemical Biosensors: A Review

This review addresses recent advances in carbon‐nanotubes (CNT) based electrochemical biosensors. The unique chemical and physical properties of CNT have paved the way to new and improved sensing devices, in general, and electrochemical biosensors, in particular. CNT‐based electrochemical transducers offer substantial improvements in the performance of amperometric enzyme electrodes, immunosensors and nucleic‐acid sensing devices. The greatly enhanced electrochemical reactivity of hydrogen peroxide and NADH at CNT‐modified electrodes makes these nanomaterials extremely attractive for numerous oxidase‐ and dehydrogenase‐based amperometric biosensors. Aligned CNT “forests” can act as molecular wires to allow efficient electron transfer between the underlying electrode and the redox centers of enzymes. Bioaffinity devices utilizing enzyme tags can greatly benefit from the enhanced response of the biocatalytic‐reaction product at the CNT transducer and from CNT amplification platforms carrying multiple tags. Common designs of CNT‐based biosensors are discussed, along with practical examples of such devices. The successful realization of CNT‐based biosensors requires proper control of their chemical and physical properties, as well as their functionalization and surface immobilization.     

Electrochemical Characteristics of Glucose Oxidase Adsorbed at Carbon Nanotubes Modified Electrode with Ionic Liquid as Binder

Multiwall carbon nanotubes (CNTs)‐modified electrode has been prepared by using ionic liquid (IL) as the binder. The as‐prepared CNTs‐IL composite modified electrode has good biocompatibility and is a suitable matrix to immobilize biomolecules. Glucose oxidase (GOx), containing flavin adenine dinucleotide as active site, stably adsorbed on modified electrode surface has resulted in the direct electron transfer. The electron transfer rate of 9.08 s^?1 obtained is much higher than that of GOx adsorbed on the CNTs papers (1.7 s^?1), and the process is more reversible with small redox peak separation of 23 mV. This may be due to the synergetic promotion of CNTs and IL to electron transfer of the protein, especially the IL as the binder, showing better electrochemical properties than that of chitosan and Nafion. Furthermore, GOx adsorbed at the modified electrode exhibits good stability and keeps good electrocatalytic activity to glucose with broad linear range up to 20 mM. Besides, the simple preparation procedure and easy renewability make the system a basis to investigate the electron transfer kinetics and biocatalytic performance of GOx and provide a promising platform for the development of biosensors.     

Binding and condensation of plasmid DNA onto functionalized carbon nanotubes: toward the construction of nanotube-based gene delivery vectors

Carbon nanotubes (CNTs) constitute a class of nanomaterials that possess characteristics suitable for a variety of possible applications. Their compatibility with aqueous environments has been made possible by the chemical functionalization of their surface, allowing for exploration of their interactions with biological components including mammalian cells. Functionalized CNTs (f-CNTs) are being intensively explored in advanced biotechnological applications ranging from molecular biosensors to cellular growth substrates. We have been exploring the potential of f-CNTs as delivery vehicles of biologically active molecules in view of possible biomedical applications, including vaccination and gene delivery. Recently we reported the capability of ammonium-functionalized single-walled CNTs to penetrate human and murine cells and facilitate the delivery of plasmid DNA leading to expression of marker genes. To optimize f-CNTs as gene delivery vehicles, it is essential to characterize their interactions with DNA. In the present report, we study the interactions of three types of f-CNTs, ammonium-functionalized single-walled and multiwalled carbon nanotubes (SWNT-NH3+; MWNT-NH3+), and lysine-functionalized single-walled carbon nanotubes (SWNT-Lys-NH3+), with plasmid DNA. Nanotube-DNA complexes were analyzed by scanning electron microscopy, surface plasmon resonance, PicoGreen dye exclusion, and agarose gel shift assay. The results indicate that all three types of cationic carbon nanotubes are able to condense DNA to varying degrees, indicating that both nanotube surface area and charge density are critical parameters that determine the interaction and electrostatic complex formation between f-CNTs with DNA. All three different f-CNT types in this study exhibited upregulation of marker gene expression over naked DNA using a mammalian (human) cell line. Differences in the levels of gene expression were correlated with the structural and biophysical data obtained for the f-CNT:DNA complexes to suggest that large surface area leading to very efficient DNA condensation is not necessary for effective gene transfer. However, it will require further investigation to determine whether the degree of binding and tight association between DNA and nanotubes is a desirable trait to increase gene expression efficiency in vitro or in vivo. This study constitutes the first thorough investigation into the physicochemical interactions between cationic functionalized carbon nanotubes and DNA toward construction of carbon nanotube-based gene transfer vector systems.     

Electrochemistry and electroanalytical applications of carbon nanotubes: a review.

This review addresses recent developments in electrochemistry and electroanalytical chemistry of carbon nanotubes (CNTs). CNTs have been proved to possess unique electronic, chemical and structural features that make them very attractive for electrochemical studies and electrochemical applications. For example, the structural and electronic properties of the CNTs endow them with distinct electrocatalytic activities and capabilities for facilitating direct electrochemistry of proteins and enzymes from other kinds of carbon materials. These striking electrochemical properties of the CNTs pave the way to CNT-based bioelectrochemistry and to bioelectronic nanodevices, such as electrochemical sensors and biosensors. The electrochemistry and bioelectrochemistry of the CNTs are summarized and discussed, along with some common methods for CNT electrode preparation and some recent advances in the rational functionalization of the CNTs for electroanalytical applications.