【作者】 肖寒；

【导师】 杨文胜；

【作者基本信息】 北京化工大学 ， 应用化学， 2007， 硕士

【摘要】 在电化学生物传感器的研究中，生物分子的固定化是一个关键问题。如何在电极表面有效地固定生物分子无论对于研究蛋白质的性质，还是研制新型电化学生物传感器都具有非常重要的意义。如果将纳米材料修饰在电极表面，基于其小尺寸效应和宏观量子隧道效应等特性，能够增大电流响应，降低检测限，大大提高检测的灵敏度，可以用于微量样品的分析。本论文采用新型的纳米片材料固定血红素蛋白分子，制备生物传感器，并研究其电化学性质。论文包括以下内容：1．采用新型的纳米材料MnO₂纳米片作为固定肌红蛋白（Mb）的载体，通过傅立叶红外（FTIR）和圆二色光谱（CD）检测发现，MnO₂纳米片固定后的Mb仍保持其原有的二级结构。利用MnO₂纳米片与Mb修饰玻碳电极，电化学测试表明，Mb在电极上实现了快速有效的直接电子转移。而对比实验发现，剥层前体层状MnO₂固定的Mb在电极上不能实现其直接电化学行为。MnO₂纳米片与Mb修饰的玻碳电极对底物H₂O₂、O₂和NaNO₂均有良好响应。此外，硫化物对Mb的催化活性有明显的抑制作用。电极具有良好的稳定性，放置14天以后，电极对H₂O₂的催化活性能保持91％。2．采用MnO₂纳米片作为固定细胞色素c（Cyt c）的载体，FTIR检测发现，MnO₂纳米片固定后的Cyt c仍保持着其原有的二级结构。电化学测试结果表明MnO₂纳米片固定的Cyt c保持了对底物H₂O₂的催化特性。论文对Cyt c与MnO₂纳米片之间进行静电组装的可能性进行了研究。交流阻抗测试表明组装过程中各层Cyt c与MnO₂纳米片的量随着层数的增加均匀增长。更多还原

【Abstract】 A very important factor in biosensor research is the immobilization of biomolecules. Immobilization of biomolecules onto electrode surfaces is important in the understanding of protein properties and also in the development of novel biosensors.Modified electrodes based on nanomaterials combined with high surface area and good electrochemistry abilities can largely improved electrical responses and the detection sensitivity. We applied the novel MnO₂ nanosheet to the immobilization of heme proteins and investigated the electrochemical properties. The main contents of the thesis are given as follows:1. A novel nanomaterial - MnO₂ nanosheet was firstly applied to the immobilization of myoglobin （Mb） as a support matrix. Fourier transform infrared （FTIR） and Circular dichroism （CD） spectra showed that Mb almost retained secondary structure in the film. In MnO₂ nanosheet film, Mb realized its direct electron transfer and gave a pair of nearly reversible cyclic voltammetric peaks, whereas no redox pair was observed for Mb/the precursor layered manganese oxide film. Moreover, the immobilized Mb displayed the feature of a peroxidase and acted in an electrocatalytic manner in the reduction of hydrogen peroxide, nitrite and oxygen. The detection of sulfides was performed via the inhibiting action on the Mb/MnO₂ nanosheet/glassy carbon electrode （GCE）. After 14 days, Mb/MnO₂ nanosheet/GCE retained 91% of its initial response to electrocatalytic reduction of hydrogen peroxide.2. MnO₂ nanosheet was also applied to the immobilization of cytochrome c （Cyt c） as a support matrix. FTIR spectra showed that Cyt c almost retained secondary structure in the film. In MnO₂ nanosheet film, the electrocatalytic manner in the reduction of hydrogen peroxide of Cyt c was retained. In additional, （Cyt c/MnO₂ nanosheet）_n layer-by-layer was fabricated on the surface of GCE. Electrochemical impedance spectroscopy was used to monitor the growth of the film. The amount of Cyt c and MnO₂ nanosheet in the bilayer increased linearly with the number of the bilayer.更多还原