酶在新型纳米结构TiO₂薄膜电极上的固定化及其生物电化学性能

【作者】 郭桐；

【导师】 康传红；

【作者基本信息】 黑龙江大学 ， 生物化学与分子生物学， 2008， 硕士

【摘要】 纳米科学与技术的发展为新型高效、稳定的生物传感器的研发提供了条件。本论文主要是针对改性纳米TiO₂与酶复合电极的制备及其生物电化学传感性能进行了研究,同时对所合成的纳米TiO₂进行了光催化活性评价。努力实现纳米技术、生物传感技术和生物科学技术的三者有机结合。主要内容及结论如下:在溶胶-水热法所合成的锐钛矿相TiO₂纳米粒子基础上,通过浸渍过程实现了银、铂和钌这三种金属离子表面修饰的纳米TiO₂粉体的合成。荧光汞灯辐射下的光催化实验结果表明,Pt的修饰提高了TiO₂纳米粒子的杀菌效果,但效果并不十分明显。Ru的修饰降低了TiO₂纳米粒子的杀菌效果。Ag的表面修饰显著地提高了TiO₂纳米粒子的杀菌效果,尤其是在日光下也能够表现出较好的杀菌效果,进一步的拓展了其应用范围。在溶胶-水热法所合成的锐钛矿相TiO₂纳米晶基础上,利用模板剂调制的SiO₂溶胶进一步合成了SiO₂-TiO₂复合纳米粒子。重点研究了复合SiO₂对纳米锐钛矿相TiO₂热稳定性及光催化活性的影响。结果表明,复合SiO₂显著地提高了纳米锐钛矿相TiO₂的热稳定性,甚至经过900℃热处理后仍然具有以锐钛矿相为主的相组成。在光催化降解罗丹明B实验过程中,经过高温热处理的复合纳米粒子样品表现出了优越于国际商品P25-TiO₂的活性,这主要与其锐钛矿相结晶度提高而同时又有着较大比表面积等有关。贵金属的修饰及结晶度的提高有利于光生电荷的传输与分离,这为研发新型高效的酶传感器提供了条件。采用光还原法合成了Au纳米粒子修饰的纳米SiO₂-TiO₂复合物（Au/SiO₂-TiO₂）,并将其应用于固定辣根过氧化物酶（HRP）,考察利用Au纳米粒子修饰的纳米SiO₂-TiO₂复合物加速HRP与玻碳电极之间的直接电子传递行为,探索研制非媒介体型的过氧化氢传感器。实验结果表明,Au在纳米SiO₂-TiO₂上的修饰提高了HRP的电化学响应,HRP/Au/SiO₂-TiO₂/GC电极的氧化还原峰电流大于HRP/SiO₂-TiO₂/GC电极的峰电流;HRP/Au/SiO₂-TiO₂/GC电极中的HRP对过氧化氢具有较强的催化作用,对H₂O₂具有快速地电流响应。更多还原

【Abstract】 The development of nano-techonology provides a new opportunity to the development of biosensors. Nanobiosening technology is revealing its superiority not only have good effect on it, but also on biosensor. This dissertation focuses on 1) fabricating novel biosensors based on new nanomaterials and nanostructures, and integrated them with microdialysis, flow injection analysis, etc. 2) establishing the bases for application of them to detect glucose, hypoxanthine and organophosphate pesticides. We are adhering to an organic combination of nanotechnology, biosensing technology and clinical researches. The details are given as follows:SiO₂-TiO₂ composite nanoparticles have been synthesized by utilizing TiO₂ nanopartilces obtained by a sol-gel method, followed by an impregnation process with Ag+, Pt+ and Ru3+ solution. The results of sterilization show that, the bactericidal effect of TiO₂ nanoparticles modified by Pt is stronger than that of TiO₂ nanoparticles, appreciably; The bactericidal effect of TiO₂ nanoparticles modified by Ru is lower than that of TiO₂ nanoparticles; The bactericidal effect of TiO₂ nanoparticles modified by Ag is obviously stronger than that of TiO₂ nanoparticles, especially under visible light, extending the application of TiO₂ nanoparticles.SiO₂-TiO₂ composite nanoparticles have been synthesized by utilizing TiO₂ nanopartilces obtained by a sol-gel method, followed by an impregnation process with SiO₂ sol. The effects of the SiO₂ on the thermal stability and photocatalytic activity of anatase nanoparticles were mainly investigated. The results show that the SiO₂ can greatly enhance the thermal stability, even having a principal anatase phase composition after thermal treatment at 900℃. During the processes of photocatalytic degradation RhB, all the as-prepared SiO₂-TiO₂ composite nanoparticles by thermal treatment at high temperature exhibit higher activity than P-25 TiO₂, which is attributed to their high anatase crystallinity and to their large surface area.Gold nanoparticles-modified SiO₂-TiO₂ nanocomposite （Au/SiO₂-TiO₂） was used to immobilize horseradish peroxidase （HRP） on a glassy carbon electrode surface for the construction of an amperometric hydrogen peroxide （H2O2） biosensor. The properties of HRP immobilized in the Au/SiO₂-TiO₂ film were characterized by the electrochemical methods. the HRP immobilized in Au/SiO₂-TiO₂/GC electrode exhibited a rapid electrocatalytical response. The good direct electrochemical behavior of HRP and electrocatalytical response to H2O2 reduction was due to the enhancement of specific surface area and the reduction of electron transfer resistance by the uniform deposition of gold nanoparticle on SiO₂-TiO₂ surface.更多还原