Effect Of Irradiated And Refluxed Silver Nanoparticles On Enzymatic Activity Of Glucose Oxidase

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.