【作者】 王海南；

【导师】 吴硕；

【作者基本信息】 大连理工大学 ， 分析化学， 2012， 硕士

【摘要】 利用纳米材料及其复合材料构建新型传感界面已经成为电化学生物传感领域的主要研究方向之一。纳米材料及其复合材料等新型材料,因其独特的性质,如催化性、磁性、表面功能性等,在传感界面中起到了重要的作用,为进一步提高电化学生物传感器的灵敏度和选择性创造了条件。本文基于二氧化钛／石墨烯纳米带、磁性介孔复合微球、磁性石墨化碳材料构建了几种电化学生物传感器,分别以半胱氨酸、苯酚、葡萄糖为底物,采用循环伏安法、计时安培法、示差脉冲伏安法等电化学分析方法对其性能进行了研究,具体如下：一、基于二氧化钛／石墨烯纳米带(TiO2/GNR)的半胱氨酸传感器通过超声制备了TiO2/GNR纳米复合材料。石墨烯纳米带能够均匀分散在二氧化钛纳米管表面,它的引入显著提高了二氧化钛的导电性,同时二氧化钛为二维平面的石墨烯纳米带支撑了空间骨架,形成了立体结构,从而更有利于底物扩散进入催化中心发生反应。与单纯二氧化钛的相比,以此复合材料构建的传感器具有更低的检测电位和更小的背景电流,所得的传感器对半胱氨酸检测的线性范围为1μM～0.485mM,灵敏度为7.384μAmM-1,在信噪比为3时最低检测限为0.09μM。二、基于介孔二氧化硅磁性复合微球的高灵敏苯酚传感器将酪氨酸酶化学交联到磁性核壳微球表面,通过磁性作用将其负载到磁性玻碳电极表面用于苯酚的检测。采用磁强计、氮气吸附脱附等温线、TEM等方法对磁性复合微球进行表征,该微球具有均匀的形貌,较大的比表面积和较强的磁性,无需其他外加固定试剂即可附着在磁性电极表面。与粘着剂固定的传感器相比,该传感器具有更快的响应速度(响应时间小于5s)和更高的灵敏度(78μAmM-1)。基于此磁性材料构建的传感器对苯酚检测的线性范围为1.0nM～101μM,最低检测限为1nM。三、基于磁性石墨化碳的葡萄糖传感器通过磁性作用将磁性碳片负载到磁性电极表面,利用EDC/NHS(?)将葡萄糖氧化酶与磁性石墨化碳材料交联,以二茂铁甲醛为媒介体对葡萄糖进行电化学分析。传感器对葡萄糖检测的线性范围分别为0.01～1.05mM和1.35～4.85mM,灵敏度分别为0.752μAmM-1和1.89μAmM-1,最低检测限为10μM。说明此材料具有良好的导电性、磁性和生物相容性,在电化学生物传感领域具有良好的应用前景。更多还原

【Abstract】 The synthesis of novel nanomaterials and the construction of nanomaterial based nano-interface for the development of electrochemical sensors have attracted considerable attentions during the past two decades due to the unique properties of nanomaterials and the good performance of nanomaterial based electrochemical biosensors. In this paper, several electrochemical biosensors were developed based on nanocomposites, including TiO2/graphene nanoribbon composite (GNR), magnetic mesoporous silica and Fe3O4nanoparticle core/shell microspheres, and magnetic graphitized carbon nanosheet, and used for the electrochemical detection of cysteine, phenol, and glucose respectively. The detailed contents are listed as follows:(1). The preparation of TiO2/Graphene nanoribbon(TiO2/GNR) nanocomposite and their applications in the selective and sensitive detection of cysteine.TiO2/GNR nanocomposite was synthesized by ultrasonically mixing the GNR and TiO2nanotube and used for the development of electrochemical sensor for cysteine detection. The GNR could homogeneously distribute on both the inner and outer surface of TiO2nanotube and form an accessible TiO2/GNR nanostructure, which was verified by the SEM images. After the nanocomposite was introduced on the surface of glassy carbon electrode, the TiO2/GNR nanocomposite modified electrode showed high electrochemically catalytic ability towards the anodic oxidation of cysteine, on which the overpotential for cysteine anodic oxidation has been reduced to+75mV. Under the optimal conditions, the as-prepared nanocomposite modified electrode showed a high sensitivity (7.384μAmM-1), and a low limit of detection (0.09μM, S/N=3). In addition, the sensor also showed a wide linear range from1.0μM to0.485mM, which could satisfy the demand of in vivo analysis real samples.(2). Magnetic loading of tyrosinase-Fe3O4/mesoporous silica core/shell microspheres for high sensitive electrochemical biosensing.A new protocol is proposed for magnetic loading and sensitive electrochemical detection of phenol via the tyrosinase cross-linked mesoporous magnetic core/shell microspheres. The mesoporous magnetic microspheres, characterized by transmission electron microscopy, N2adsorption/desorption isotherms, and magnetic curve displays high capacity for enzyme immobilization and strong magnetism to adhere to the magnetic electrode surface without any additional adhesive reagent. The biosensor exhibits a wide linear response to phenol ranging from1.0nM to1.0μM, a high sensitivity of78μAmM-1, a low detection limit of1nM, and a fast response rate (less than5s). The proposed method is simple, rapid, inexpensive and convenient in electrode renewal, which is recommended as a promising experimental platform for wider applications in biosensing.(3). Magnetic loading of glucose oxidase-magenetic graphitized carbon nanosheet for high sensitive electrochemical biosensing of glucose.A magnetic glucose biosensor was developed by magnetically loading the glucose oxidase cross-linked magnetic graphitized carbon (GOD-MGC) nanosheet on magnetic electrode surface.. Electrochemical impedance showed the carbon nanosheet had good conductivity, which was even comparable to the carbon nanotube. Due the good electrochemical conductivity and the strong magnetic property of MGC which would adsorb on the magnetic electrode surface without the addition of any additional adhesive reagent, the as-prepared GOD-MGC modified electrode exhibited a high sensitivity of94.63nAmM-1towards the detection of glucose, a linear response ranging from0.01to1.05mM and from1.35to4.85mM, and an acceptable limit of detection of10μM. The proposed method is simple, rapid, inexpensive and convenient in electrode renewal, which is recommended as a promising experimental platform for wider applications in biosensing.更多还原