Effects of self-assembled monolayers on amperometric glucose biosensors based on an organic-inorganic hybrid system

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• 作者：Huihui Wang^a  ; [Author Vitae] ; Hitoshi Ohnuki^a ; ^{ohnuki@kaiyodai.ac.jp}  ; [Author Vitae] ; Hideaki Endo^b  ; [Author Vitae] ; Mitsuru Izumi^a  ; [Author Vitae]
• 关键词：Biosensor ; Glucose oxidase ; Self-assembled monolayer ; Langmuir&ndash ; Blodgett film ; Prussian Blue
• 刊名：Sensors and Actuators B ; Chemical
• 出版年：2012
• 期刊代码：161_09254005
• 类别：et
• 出版时间：20 June, 2012
• 卷：168
• 期：Complete
• 页码：249-255
• 文件大小：594 K

摘要

Ultrathin-form amperometric glucose biosensors have been fabricated on gold substrates by using self-assembled monolayers (SAMs) of carboxylic acid groups (COOH). The glucose oxidase (GOx) was covalently immobilized on the SAMs and covered with Langmuir-Blodgett films including nanometer-sized clusters of Prussian Blue (PB) playing a role of mediator for glucose detection, which makes the present sensor, Au/SAM/GOx/PB, work at very low potentials of approximately 0.0 V vs. Ag/AgCl. An amperometric biosensor comprising a SAM of 4-mercaptobenzoic acid (MBA) exhibited a fast response current of 3 s, a detection limit of 12.5 渭M, a high sensitivity of 50 nA/(cm² mM), and a long-term stable linearity ranging from12.5 渭M to 70 mM. The sensitivity is significantly affected by the conductivity of the SAM layer. The analysis of the electron transfer confirmed a high conductive nature of MBA among carboxylic acid groups. The obtained linearity in a high-concentration region is attributed to both the ultrathin nature and high electron transfer of the MBA SAM.