基于复合碳纳米纤维的多酚漆酶生物传感器研究

发布时间：2018-01-13 02:28

本文关键词：基于复合碳纳米纤维的多酚漆酶生物传感器研究　出处：《江南大学》2016年博士论文　论文类型：学位论文

【摘要】：电化学生物传感器作为一门多学科交叉的高新技术为检测水体污染物提供了一种简便、高效、快速、低成本、准确的检测方法,在诞生至今的几十年间获得了蓬勃发展。然而,稳定性差、寿命短仍是限制电化学生物传感器实际应用的主要问题,在传感器的酶电极修饰层引入纳米材料是一种有效提高传感器灵敏度,提升传感器稳定性和使用寿命的方法。碳纳米纤维作为一种性能优异的电极材料已经被广泛应用在能源环境等领域,其在电化学生物传感器中的应用研究较少。本课题将电纺碳纳米纤维结合漆酶构建新型电化学生物传感器用于水体环境中邻苯二酚和对苯二酚的检测,并通过一系列合成手段制备功能化复合碳纳米纤维作为传感器电极修饰材料以期促进直接电子转移,进一步提高传感器的响应灵敏度和稳定性,拓宽检测线性范围。主要研究内容和结论如下:结合静电纺丝技术和高温碳化工艺制备碳纳米纤维,将所制备的碳纳米纤维结合漆酶和Nafion溶液通过包埋法制得酶修饰电极。采用拉曼光谱、傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)等表征手段对碳纳米纤维及修饰电极进行结构成分和形貌表征。并利用循环伏安和计时安培法的电化学测试方法研究了固定漆酶的电化学行为及该电极对环境污染物邻苯二酚的电催化和传感性能。该传感器灵敏度高达41μA/m M,检测限为0.63μM,线性范围为1—1310μM,响应时间在2秒内。此外该传感器被成功应用于水环境中邻苯二酚检测。该研究拓展了电纺碳纳米纤维在酶基生物传感器上的应用研究。为了提高传感器的响应灵敏度,降低检测限,通过碳化还原、水热还原、静电吸附自组装等方法实现碳纳米纤维表面功能化,制备增敏效果更好的复合碳纳米纤维,同时使用检测灵敏度更高的线性扫描伏安和方波伏安法检测水中的对苯二酚、邻苯二酚。所制备的复合碳纳米纤维分别为表面载有Ni Cu合金纳米颗粒的复合碳纳米纤维(Ni Cu CNFs)、表面修饰Zn O纳米颗粒的复合碳纳米纤维(Zn O/CNFs)和表面负载石墨烯片的复合碳纳米纤维(G/CNFs)。利用FT-IR、SEM、拉曼光谱、X-射线衍射(XRD)、透射电子显微镜(TEM)等现代分析测试手段对复合碳纳米纤维的形貌结构进行表征。同样使用Nafion通过包埋法将这些复合纳米纤维结合漆酶共同修饰在传感器电极表面,构建新型生物传感平台。这些复合碳纳米纤维分别通过表面功能化金属合金颗粒、金属氧化物颗粒和石墨烯来增加其电活性表面积,促进漆酶活性中心和电极表面之间的直接电子转移,同时发挥协同催化作用,提高传感器的响应灵敏度。研究结果表明固定酶表现为准可逆的电子传递,电化学反应为表面控制氧化还原反应过程,依照法拉第定律计算的电极表面的电活性漆酶的表面覆盖率均高于文献报道的理论值。该三种漆酶基生物传感器都具有高灵敏度、低检测限和宽线性检测范围,并都成功应用于湖水样品中多酚污染物的痕量检测。宽线性检测范围生物传感器在环境污染物的在线监测方面越来越受到重视,为了拓宽传感器的检测范围,本课题通过“一步法”在含有载镍碳纳米纤维(Ni CNFs)、漆酶和多巴胺的混合溶液中合成了PDA-Lac-Ni CNFs复合物。再使用一个磁性玻碳电极利用磁性分离固定的方法将上述复合物固定在电极表面制备出新型生物传感器并用于邻苯二酚的分析检测。该方法实现了漆酶在碳纳米纤维表面的定向固定,提高了电子转移速率和传感器的响应灵敏度,镍纳米颗粒增大了Ni CNFs的电活性表面积,同时提供了大量的酶固定位点。玻碳电极表面活性漆酶的表面覆盖率高达8.31×10~(-10) mol/cm~2,漆酶的表观米氏常数app MK为0.31 m M。制备的漆酶基生物传感器应用于邻苯二酚的检测展现了高的灵敏度,低的检测限和极宽的检测范围,同时拥有好的重复重现性、选择性和稳定性并成功应用于湖水水样中邻苯二酚的检测。该研究为制备宽检测范围酚类生物传感器提供了技术支持和理论依据。
[Abstract]:Electrochemical biosensor as a high-tech interdisciplinary provides a convenient, efficient, fast, low cost for detecting water pollutants, accurate detection method, obtained a rapid development in the decades since its birth. However, poor stability, short service life is still the main problems limit the practical application of electrochemical biosensors, the introduction of nano material in enzyme electrode modified layer sensor is an effective method to improve the sensitivity of the sensor, the sensor stability and service life. As a kind of excellent electrode material of carbon nano fiber has been widely used in the fields of energy and environment, the application study in electrochemical biosensors. The electrospinning carbon nanofibers with laccase to construct a new electrochemical biosensor for the detection of catechol and hydroquinone in water environment, and through a The synthesis of a series of preparation methods of functional composite nano carbon fiber as sensor electrode material in order to promote the direct electron transfer, further improve the sensor response sensitivity and stability, widen the linear range of detection. The main research contents and conclusions are as follows: the preparation of carbon nanofibers by electrostatic spinning technology and high temperature carbonization process, the preparation of carbon nanotubes the combination of laccase and Nafion fiber prepared by solution prepared by embedding enzyme modified electrode. Using Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) were characterized by means of composition and morphology characterization of carbon nano fiber and modified electrode. And the electrochemical cyclic voltammetry and immobilization of laccase the electrochemical test method of chronoamperometry and the electrode for pollutants of catechol electro catalysis and sensing properties of the sensor sensitivity. Up to 41 A/m M, the detection limit is 0.63 M, the linear range is 1 - 1310 M, the response time is within 2 seconds. In addition the sensor was successfully applied in the detection of catechol in water environment. The study extends the application of electrospun carbon nanofibers in enzyme based biosensors. In order to improve the response the sensitivity of the sensor, lower detection limit, through carbonization reduction, hydrothermal reduction, electrostatic adsorption function of carbon nano fiber surface by self-assembly method, composite carbon nanofibers prepared by sensitizing effect is better, and at the same time using linear scanning volt high sensitivity wave voltammetry detection in hydroquinone, catechol. The composite carbon nanofibers were prepared composite carbon nanofibers surface containing Ni Cu alloy nanoparticles (Ni Cu CNFs), the composite carbon nano fiber surface modified Zn nanoparticles O (Zn O/CNFs) and the surface load of stone Carbon nano fiber composite graphene sheet (G/CNFs). By using FT-IR, SEM, Raman spectroscopy, X- ray diffraction (XRD), transmission electron microscopy (TEM) morphology and other modern analytical methods of composite carbon nanofibers were characterized by using Nafion. The same embedding the composite nanofibers with laccase the common surface modification on the electrode of the sensor, the construction of new biosensing platforms. These carbon nano fiber composite by surface functionalization of metal alloy particles, metal oxide particles and graphene to increase the electroactive surface area, promote the direct electron paint enzyme activity center and electrode surface transfer, also play a synergistic catalytic effect, improve the response sensitivity the sensor. The research results show that the immobilized enzyme showed quasi reversible electron transfer, electrochemical reaction to control surface redox reaction process, calculated in accordance with Faraday's law The surface electric activity of laccase electrode surface coverage rate were higher than those reported in the literature. The theoretical values of the three kinds of laccase based biological sensor has high sensitivity, low detection limit and wide linear range of detection, and successfully applied to the detection of trace pollutants in water samples of polyphenol. Wide linear detection range of the biosensor more attention in the on-line monitoring of environmental pollutants and, in order to broaden the detection range of the sensor, the "one-step" in containing carbon nano fiber loaded with nickel (Ni CNFs), the mixed solution of laccase and dopamine synthesis in the PDA-Lac-Ni CNFs complex. Then use a magnetic glassy carbon electrode by magnetic separation method will be fixed the complexes were immobilized on the electrode surface producing new biosensor and used to analyze the detection of catechol. The method realizes directional laccase on the surface of carbon nanofibers Fixed, improve the response rate and the sensitivity of sensor for electron transfer, nickel nanoparticles increases the electrical activity of Ni surface area of CNFs, and provides a large number of sites of enzyme immobilization. The surface of the glassy carbon electrode surface activity of the laccase coverage rate as high as 8.31 * 10~ (-10) mol/cm~2, laccase apparent Michaelis constant app MK detection 0.31 m M. prepared based laccase Biosensor Applied to catechol showed high sensitivity, low detection limit and wide detection range, repeated at the same time have a good reproducibility, selectivity and stability of detection and successfully applied to the lake water samples. The catechol provides technical support and theoretical basis for this study for the preparation of a wide range of detection of phenol biosensor.

【学位授予单位】：江南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ342.742;TP212

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