【作者】 曲松；

【导师】 孔继烈；

【作者基本信息】 复旦大学 ， 分析化学， 2007， 博士

【摘要】 纳米材料和生物体系相结合的相关研究是纳米生物学中很有前景的一个研究领域。将纳米材料独特的电子学,光学和催化特性与生物分子高度选择性的催化能力和识别能力结合起来,构建功能化的复合界面系统,对发展纳米电子元件和生物传感器具有重要意义。作为一种新型的碳纳米材料,自从1991年被Iijima发现以来,碳纳米管（CNTs）因其优异的物理和化学性质,而成为人们广泛研究关注的焦点。由于其较大的比表面积,良好的生物相容性和丰富的电子学性质,碳纳米管被认为是一种构建新型生物传感器的理想材料。现在已经发展了众多的基于碳纳米管的酶生物传感器。在大多数情况下,CNTs修饰电极由滴涂法制备。但是,这种方法制备的修饰电极,其稳定性和应用性有一定局限,妨碍了其在电化学中的进一步应用。为了克服这些问题,拓展CNTs在纳米器件和生物传感器中的潜在应用价值,建立新型的多样性地将CNTs和酶共同修饰到电极表面的可靠方法十分必要。另一方面,近年来,把CNTs和其它材料整合起来,制备复合功能材料也引起了研究者相当的兴趣。尽管在CNTs修饰电极的构建方面已经有了部分创造性的工作,但是,随着CNTs和纳米技术的发展,CNTs及其复合材料的制备、性质及应用仍然吸引了全世界众多的研究者而成为热点领域。本论文内容共分七章,主要摘要如下:在第一章中,对CNTs的发展,制备、功能化及其应用进行了较系统全面的综述。在第二章中,通过磁性负载碳纳米管/纳米四氧化三铁（CNTs/Fe₃O₄）于电极上,发展了一种新型的电化学传感平台。为了实现传感器的构建理念,首先在CNTs存在的碱性溶液中,Fe²⁺和Fe³⁺化学共沉积形成纳米Fe₃O₄于CNTs上。合成的磁性纳米复合材料整合了CNTs和Fe₃O₄的优点,为电化学传感装置带来了新的改进,从而提供了一种把CNTs负载到电极表面的新方法。对磁性纳米复合物修饰电极的制备和表现进行了研究。修饰电极对过氧化氢显著的电化学催化性能使得低电位下检测葡萄糖成为可能。本文中磁性负载碳纳米管复合物的概念在基于CNTs的生物传感装置的创建和电化学装置的发展上有进一步的应用价值。在第三章中,将开口截断的多壁碳纳米管（MWNTs）在硝酸铁溶液中水热反应后煅烧,从而制备了填充γ-Fe₂O₃的碳纳米管。磁性粒子通过湿法化学填充到碳管内部。产物用透射电镜（TEM）、能量分散X射线荧光（EDX）、X射线粉术衍射（XRD）、电子结合能谱（XPS）和磁力计（VSM）进行了表征。制备得到的磁性碳纳米管（M-MWNTs）能够在溶液中得到很好的分散,而且可以很方便的进行磁性分离。对染料的吸附实验证明其是一种移除中性红和亚甲基兰的有效吸附剂。和其它吸附剂相比,M-MWNTs不仅有着很好的吸附能力,而且可以在外磁场作用下很方便的操作。把碳纳米管的优良的吸附能力和磁性粒子的磁学性质结合起来,使得磁性碳纳米管成为了一种应对环境污染的有力工具。在第四章中,用磁性诱导组装的方法构建了一种基于磁性碳纳米管的新型的电化学纳米生物传感器。在磁场作用下,M-MWNTs和酶组装成了复合多层的功能化界面。辣根过氧化物酶（HRP）作为一种模型蛋白,展示了所构建的纳米生物传感器的最终性能表现。用扫描电子显微镜（SEM）、紫外可见光谱和电化学技术对组装过程进行了表征。最终形成的M-MWNTs/HRP三维结构的复合膜显示了优异的稳定性、生物兼容性和电化学性质。结果表明,磁性组装能够有效增加酶和碳纳米管在电极表面的功能化密度,从而提升传感器的性能表现。这里我们提供了一种以可控方式组装碳纳米管和生物分子形成纳米生物功能化界面的通用方法。在第五章中,用电沉积的方法把氧化锆、碳纳米管和肌红蛋白沉积到电极表面形成纳米生物复合膜。膜中的肌红蛋白实现了直接电化学,并且保持了对过氧化氢的高度催化能力。和单独的碳纳米管或者氧化锆构建的传感器相比,通过简单的一步电沉积方法构建的生物传感器展现了对过氧化氢更宽的检测范围和更低的检测限。这里,我们提出了一种简单有效的组装CNTs、ZrO₂和酶形成纳米复合体系的方法,可以应用于其它生物体系。在第六章中,研究了血红蛋白（Hb）在硅酸盐纳米管（SNT）修饰电极上的直接电化学行为。首先在乙醇/水的混合溶液体系中通过水热法合成了镍镁杂化的硅酸盐纳米管。这种新型的硅酸盐纳米管具有尺寸均一、端口开放和表面亲水等特点。用TEM、EDX和XRD对产物进行了表征。然后把SNT修饰于电极表面,并对修饰膜用SEM和EIS进行了表征。SNT修饰电极上的Hb实现了直接电子传递,并保持了对过氧化氢的高度催化活性。可以预期,SNT修饰电极能在生物传感器和生物燃料电池中得到进一步的应用。第七章是对论文工作的总结和下一步工作的展望。更多还原

【Abstract】 The integration of nanomaterials with biological systems is an attractive research area of nanobiotechnology.The construction of functional hybrid systems that incorporate the highly selective catalytic and recognition properties of biomolecules with the unique electronic,photonic,and catalytic features of nanomaterials are of great importance for potential applications in nanoelectronic devices and biosensors. As a new type of carbon nanomaterial,carbon nanotubes（CNTs）have been the focus of intensive study due to their excellent physical and chemical properties since their discovery by Iijima in 1991.They are considered as promising building blocks for the construction of novel biosensors because of their high surface area,good biocompatibility and rich electronic properties.Now numerous CNTs-based biosensors have been developed with a variety of enzymes.In most case,CNTs modified electrodes have been prepared by drop costing method.However,the insufficient reactivity and stability of such modified electrodes seem to impede their applications.To overcome these problems and exploit the potential applications in future biosensors and nanodevices,it is necessary to develop versatile reliable approaches to assemble or integrate CNTs onto solid surfaces.Recently,composite materials based on integration of CNTs and some other materials have gained growing interest.Although some creative efforts on the construction of the CNTs-based electrodes have almost been made,with the further development of CNTs and nanotechnology,the study on the preparation,properties and application of CNTs and its composite materials is still a hot topic attracting lots of researchers in the world.This thesis is divided into seven chapters and the details are given as follows:In chapter 1,we present the systemic overview on the development of CNTs.The preparation of CNTs,the functionalization of CNTs and its application are described in detail.In chapter 2,an electrochemical sensing platform was developed based on the magnetic loading of CNTs/Fe₃O₄ composite on electrodes.To demonstrate the concept,Fe₃O₄ was deposited by the chemical coprecipitation of Fe²⁺and Fe³⁺in the presence of CNTs in an alkaline solution.The resulting magnetic nanocomposite brings new capabilities for electrochemical devices by combining the advantages of CNTs and Fe₃O₄ and provides an alternative way for loading CNTs on electrodes. The fabrication and the performances of the magnetic nanocomposite modified electrodes have been described.The marked electrocatalytic activity toward hydrogen peroxide permits effective low-potential amperometric biosensing of glucose.The concept of the magnetic loading of CNTs nanocomposite has great promise for creating CNTs-based biosensing devices and expands the scope of CNTs-based electrochemical devices.In chapter 3,the multi-walled carbon nanotubes（MWNTs）filled withγ-Fe₂O₃ nanoparticles have been prepared via hydrothermal reaction of shortened MWNTs in ferric nitrate solution and subsequent calcinations.Magnetic nanoparticles have been introduced into MWNTs via wet chemical method.The resulting products were characterized by TEM,EDX,XRD,XPS,and VSM.The prepared magnetic MWNTs （M-MWNTs）can be well dispersed in the water and can be easily magnetic separated from the medium.The adsorption test demonstrates that it is a superior absorbent for the removal of dyes（NR and MB）.Compared with other absorbents,the M-MWNTs not only have high adsorption efficiency to dyes,but also can be easily manipulated by external magnetic field.The combination of the superior adsorption properties of MWNTs and the magnetic properties of Fe₂O₃ nanoparticles makes it became a powerful separation tool to deal with environmental pollution.In chapter 4,a new type of electrochemical nanostructured biosensor based on CNTs has been constructed by magnetic assembly method.The multilayered functional platform could be assembled using M-MWNTs and enzyme with the aid of magnetic field.The Horseradish Peroxidase（HRP）was employed as a model enzyme to demonstrate the final performance of the nanostructured biosensor.SEM,UV-vis spectroscopy and electrochemical techniques were used for characterization of assembly process.The resulting three-dimensional M-MWNTs/HRP multilayer films have showed satisfactory stability,biocompatibility and electrochemical properties. The results showed that the magnetic assembly method enhanced the density of CNTs and the amount of enzyme loaded on the electrode,leading to the improvement of the behavior of the biosensor.Our present study may provide a general way to the construction of nanostructure biofunctional surfaces of carbon nanotubes in a highly controllable manner,while integrating the highly catalytic properties of biomolecules.In chapter 5,a nanobiocomposite film consisted of zirconia,MWNTs and Myoglobin（Mb）was electrochemically deposited on the electrode.Mb immobilized in the film has realized direct electrochemistry and kept high electrocatalytic efficiency toward H₂O₂.The proposed biosensor via a simple one-step electrodeposition method displayed a broader linear range and a lower detection limit for H₂O₂,as compared with those CNTs or ZrO₂ based biosensor.The present strategy provides a simple and effective method to assemble CNTs,ZrO₂ and enzyme nanohybrid on the electrode and can be application to the other biosystems.In chapter 6,direct electrochemistry of hemoglobin（Hb）at silicate nanotubes（SNT） modified electrode was studied.Firstly,this hybrid silicate nanotube was prepared by a hydrothermal process in a mixed water/ethanol solvent system.This opened nanotube has homogeneous diameter and its surface is hydrophilic.The resulting products were characterized by TEM,EDX,and XRD.Then the SNT coated electrode was prepared and the film was characterized by SEM and electrochemical impedance spectroscopy（EIS）.Hb at SNT electrode has realized direct electrochemistry and kept high electrocatalytic efficiency toward H_O2.It could be anticipated that the SNT modified electrode could be used in biosensors and biofuel cells.Chapter 7 is the summary of this thesis.Meanwhile,the direction of related research is also proposed.更多还原