【作者】 曲艺；

【导师】 陆维昌；

【作者基本信息】 华东师范大学 ， 物理化学， 2010， 硕士

【摘要】 为了提高葡萄糖氧化酶电极的性能,人们尝试了多种材料来固定葡萄糖氧化酶(GOD)。金属纳米颗粒表面积大,吸附能力强,能够很牢固地吸附酶等生物分子,同时金属纳米颗粒还具有生物相容性好、催化效率高等特点,金属纳米颗粒广泛应用于酶的固定。研究表明,金纳米颗粒(AuNPs)具有从周围环境中获取电子的能力,这种能力可以加速GOD催化过程中活性中心(FAD)传递电子的速率,从而起到增强酶活性的作用。与AuNPs相比,银纳米颗粒(AgNPs)对GOD活性的影响要复杂的多。本文通过对AgNPs进行光照、回流等处理,意在探讨AgNPs对GOD活性的影响。光照的AgNPs对GOD活性的影响。将光照不同时间的AgNPs与GOD作用形成GOD-AgNPs异质体,考察GOD-AgNPs异质体活性的变化。光照的AgNPs可以抑制GOD的活性。延长光照时间,AgNPs对GOD活性的抑制作用增强。本实验主要利用UV-vis吸收光谱、Zeta-电位、TEM和XPS等表征手段对AgNPs的光照过程进行跟踪。实验结果表明,光照可以改变AgNPs的表面组成和结构。Ag+浓度的增加可以抑制GOD的活性,AgNPs表面结构的变化,也会影响固定到AgNPs上GOD构象的变化。初步探讨了AgNPs的光照过程对GOD活性的抑制作用。AgNPs的回流对GOD活性的影响。实验发现经过较短时间回流的AgNPs对GOD的活性有抑制作用。延长AgNPs的回流时间,AgNPs对GOD活性的抑制作用减弱,回流一定时间的AgNPs可以增强GOD活性。本实验主要利用UV-vis吸收光谱、DLS等表征手段对AgNPs的回流过程进行跟踪,发现随着回流时间的延长,AgNPs的粒径逐渐增大。在回流不同时间的AgNPs上固定时,GOD的构象变化不同,GOD-AgNPs异质体的活性不同。探讨了AgNPs的回流过程对GOD生物活性抑制和增强的作用。不同形貌的纳米银对GOD活性的影响。利用光照和热熟化的手段得到不同形貌的片状纳米银,包括三角片状、六角片状和圆片状的纳米银。通过UV-vis吸收光谱等表征手段,对不同形貌的片状纳米银的形成过程进行跟踪,探讨了不同形貌的片状纳米银的形成机制。采用电化学的方法考察不同形貌片状纳米银对GOD活性的影响。实验结果表明,由于对H202的催化能力不同,六角片状和圆片状的纳米银对GOD活性的影响不尽相同。更多还原

【Abstract】 In order to improve the performance of glucose oxidase biosensor, a lot of materials were employed to immobilize glucose oxidase. Metal nanoparticles exhibit interesting properties such as a large surface-to-volume ratio, strong adsorption ability that make them attaching enzyme and other biological molecules firmly. Metal nanoparticles also have good biocompatibility and high catalytic efficiency. Metal nanoparticles are widely used in enzyme immobilization. Discoveries have demonstrated that gold nanopaticles (AuNPs) have the capability to obtain electronic from the surrounding environment. This capability can accelerate electron transfer rate of the active site (FAD) in glucose oxidase (GOD) catalytic process, which can enhance enzyme activity. The effect of silver nanoparticles (AgNPs) on the GOD activity is much more complicated than that of AuNPs. AgNPs with different irradiation and refluxing time were used to investigae the effect nanoparticles on the GOD activity.Effect of irradiated AgNPs on the GOD activity. The GOD-AgNPs hybrids were formed by mixing GOD and AgNPs with different irradiation time, then their activity were studied. We found that the irradiated AgNPs can inhibit the GOD activity. Increasing the irradiation time the activity of the GOD-AgNPs hybrid decreased. To investigate the experiment process described above, the monitoring methods of TEM、UV-vis、XRD、XPS were used. The results showed that, irradiation can change the surface composition and structure of AgNPs. Increasing concentration of Ag+ can inhibit the GOD activity, change of AgNPs surface structure was also affect the conformational of GOD immobilized onto AgNPs. We study the inhibitory effect of AgNPs irradiation on GOD activity preliminary.Effect of refluxed AgNPs on the GOD activity. It was found that AgNPs with a short refluxing time can inhibit the GOD activity. the inhibitoty effect of AgNPs reduced along with the refluxing time. AgNPs with a period of refluxing time can enhance the GOD activity. Various methods, such as UV-vis spectra, dynamic light scattering (DLS) were employed to probe into AgNPs refluxing process. It found that as the refluxing time increasing, AgNPs size increased. Conformational change of GOD is different when GOD immobilized onto AgNPs with different refluxing time. In this chapter we discussed preliminary that the GOD activity was influence by the refluxing process of AgNPs.Effect of different shape of AgNPs on the GOD activity. By light irradiating and heat aging we get AgNPs of different shape, which including triangular sheet、hexagonal and round sheet of AgNPs Sheet. During the reaction period, the monitoring method such as UV-vis spectra is used to investigate the shape of AgNPs,. The formation mechanism of AgNPs of the different shape was discussed. Electrochemical method was used to investigate the effect of AgNPs with different shape on the GOD activity. The results indicated that due to the different catalytic ability on H2O2, the effect of hexagonal sheet and circular sheet of AgNPs on the GOD activity was different.更多还原