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I
硕士学位论文
摘 要
电化学生物传感器研究内容十分丰富，是生物分析技术的重要领域之一，近年来已取得大量研究成果，并获得广泛应用。纳米材料由于具有大比表面积、良好生物活性、强吸附能力等特性，能显著改善生物传感器的性能。它的引入，使电化学生物传感器的研究发展到更高的阶段。在此背景下，本论文以组装有序纳米体系为出发点，依次采用原位自组装法、模板法和种子生长法构建了基于新型纳米复合材料的生物传感界面。所制备的电化学酶传感器方法简单，性能优良，可实现对目标物的高灵敏检测。具体内容如下：
(1) 通过在电极表面原位自组装贵金属纳米粒子构建了一种新颖的过氧化氢(H2O2) 传感器。首先在电极表面电沉积聚丙烯酸(PAA)，然后化学吸附一定比例的铂和钯双金属离子，再用水合肼将其还原成零价金属，其纳米粒子均匀分散在PAA网络中。由于贵金属微粒的电催化作用，该修饰电极对H2O2表现出了良好的电流响应。优化条件下，我们得到该传感器线性范围500nM -20mM，检测下限500nM，表明该传感器检测灵敏。通过改变功能聚合物、金属离子和固定生物分子，该方法有望构建多种化学与生物传感器（第2章）。
(2) 提出了一种简单、生物友好型的基于羟基磷灰石纳米线阵列(HANWA)的传感器制备方法，并用于构建氰化物生物传感器。采用模板法电化学沉积，制备了生物相容性好、具有大比表面积、空间取向和大量吸附位点的HANWA。辣根过氧化物酶(HRP) 通过壳聚糖(CHIT) 包埋固定于纳米线阵列表面，利用氰化物对HRP活性的抑制作用实现该目标物的电化学测定。该氰化物生物传感器具有空间取向好、检测灵敏（检测下限达0.6 ng mL-1）、响应快、再生迅速等优点，有望应用于食品工业和环境中的毒物监测（第3章）。
(3) 首次运用种子生长法制备铁氰化钴纳米颗粒(CoNPs)。以粒径3.5 nm的金颗粒作为种子，以多壁碳纳米管(MWCNT)作为生长支架，一步法合成CoNPs，成功制备了CoNPs /CNT修饰的电极。固定上葡萄糖氧化酶，该传感界面即可用于葡萄糖的检测。金纳米种子桥连了CoNPs和CNT，形成一种巧妙的纳米复合物。CNT的协同作用有利于铁氰化钴纳米复合材料发挥优良的电化学催化性能。该传感器的制备过程简单、快速，有望推广到其它类别金属铁氰化物的纳米体系的构建（第4章）。
关键词：原位自组装；模板法；种子法；贵金属纳米粒子；羟基磷灰石纳米线阵列；
铁氰化钴纳米复合材料
II
几种无机/有机纳米复合材料的电化学酶传感器研究
Abstract
Electrochemical biosensor whose research contents are rich, is one of the important areas of biotechnology analysis. In recent years, a large number of research results has been made, and is widely available. Nano-materials have large specific surface area, good biological activity, high adsorption capacity and other characteristics, can significantly improve the performance of biosensors. With the introduction of nano-technology, the development of biosensors comes to a more advanced stage. In this paper, in order to assemble ordered nano-systems to build several new type of electrochemical sensing interface with excellent performance, we use situ self-assembly method，template method and seed-mediated method respectively. The developed biosensors have the advantages of simple fabricaiton, excellent performance, good reliability and easy regeneration. The details are summarized as follows:
(1) In chapter 2, a novel amperometric sensor for hydrogen peroxide (H2O2) was developed based on noble metal nanoparticles in-situ formed on the electrode surface. Poly(acrylic acid) (PAA) was first electrodeposited onto a gold electrode. Then a certain proportion of platinum and palladium ions were chemically adsorbed within the PAA network, and subsequently reduced by hydrazine hydrate to yield zerovalent metal. The resultant metal nanoparticles were uniformly dispersed in the PAA network. Thus modified electrode showed good current response to H2O2 due to the catalytic activity of Platinum and Palladium particles. Under optimal conditions, linear relationship was observed for H2O2 reduction in the concentration range from 500nM to 20mM at the applied potential of ?0.1V and the detection limit was 500nM. The resulted sensor shows sensitive detection. By changing the functional polymers, metal ions and fixed biological molecules, the method is expected to build a variety of chemical and biological sensors.
(2) In chapter 3, we report a simple, biomolecular friendly protocol for the fabrication of a hydroxyapatite nanowires array (HANWA) biosensor and its application to cyanide sensing. The HANWA is performed by template-assisted electrodeposition and it has a large surface area, spatial orientation and numbers of adsorption sites. The electrochemical biosensor for the determination of cyanide through its inhibitory effect on horseradish peroxidase (HRP) encapsulated by chitosan (CHIT) on the platform of hydroxyapatite nanowires array is demonstrated. A sensitive detection limit of 0.6 ng mL-1 was obtained for cyanide. The proposed HANWA/CHIT-HRP biosensor has the advantages of spatial resolution, high sensitivity, rapid regeneration and fast response associated with individual
III
硕士学位论文
nanowires. The new device holds great promise for food industrial and environmental monitoring of toxins.
(3) In chapter 4, for the first time, we introduced the seed-mediated method to the growth of cobalt hexacyanoferrate nanoparticles (CoNPs), using 3.5 nm gold nanoparticles as seeds and multiwalled carbon nanotubes (MWCNT) as growth scaffold, one-step synthesized CoNPs and prepared CoNPs/CNT modified electrodes successfully . Combined with glucose oxidase, the sensing surface is applied as a biosensor for glucose. The nanoseeds bridge the CoNPs and CNTs to form a smart nanocomposite. The synergy of CNT is good for cobalt hexacyanoferrate nanocomposites to play excellent electrochemical catalytic performance. The synthesis and fabrication/modification is simple and fast, expected to be extended to other types of nano-iron cyanide system.
Key Words: Situ self-assembly method; Template method; Seed-mediated method; Noble
metal nanoparticles; Hydroxyapatite nanowires array; Cobalt hexacyanoferrate nanocomposite
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