| Summary: | 碩士 === 國立雲林科技大學 === 電子工程系 === 103 === In this study, an electrochemical glucose biosensor was successfully fabricated by using 3-mercaptopropyl-trimethoxysilane (MPTMS) and 3-aminopropyl-trimethoxysilane (APTES) as a linker molecule combined with the gold nanoparticles (AuNPs) on ITO electrode. AuNPs was self-assembly modified in various time (4 hours, 8 hours, and 12 hours, respectively) by different linker molecules (MPTMS, APTES) on the ITO electrode surface for glucose detection. The surface properties have been investigated by using FE-SEM and UV-Vis spectroscopy. The sensing characteristics of the biosensor have been analyzed for the sensitivity, linearity and electrochemistry properties by using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) measurement systems. The results show that the –NH2 functionality in the APTES binder molecule is favorable for large amount of AuNPs, which leads to higher electron transfer and electrocatalytic activity.
The nafion was applied as an immobilization material due to the high chemical stability and biocompatibility. The enzyme composite solution was dropped on the AuNPs-APTES/ITO electrodes as a glucose biosensor, enzyme composite solution. The biosensor provided a linear response to the glucose over the concentration range up to 300 mg/dL (16.7 mM) with a sensitivity of 4.5 μA/mM．cm2 and a detection limit of 61 μM. The Michaelis–Menten constant (K_m^app) was found to be 12.6 mM. It is better than the AuNPs-MPTMS/ITO electrodes based glucose biosensor. The biosensors also demonstrated a high selectivity and a life time of at least 1 weeks. These results indicate that AuNPs-APTES/ITO electrodes make it promising for the fabrication of glucose sensors.
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