Preparation, characterization and application of alkanethiol self-assembled monolayers modified with tetrathiafulvalene and glucose oxidase at a gold disk electrode
Preparation, characterization and application of alkanethiol self-assembled monolayers modified with tetrathiafulvalene and glucose oxidase at a gold disk electrode
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DOI：
10.1016/s0022-0728(02)00753-2
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发表时间：
2002-05-17
影响因子：
4.5
通讯作者：
Pingarrón, JM
中科院分区：
文献类型：
--
作者：
Campuzano, S;Gálvez, R;Pingarrón, JM
报道了一种利用自组装单分子层（SAM）修饰电极制备酶电化学生物传感器的关键研究。关于影响在金盘电极（AuE）上获得自组装膜的变量，评价了所采用的烷醇的类型、其浓度、形成的时间和温度以及介质的组成。在基于SAM修饰金电极的葡萄糖生物传感器中，比较了几种氧化还原介体对葡萄糖酶促氧化的性能。两种葡萄糖氧化酶（GOx）的SAM修饰的金电极上的固定方法进行了测试：共价结合使用1-（3-二甲氨基丙基）-3-乙基碳二亚胺和N-羟基磺基琥珀酰亚胺（NHSS），和交联与戊二醛。的交联方法产生的斜率的基板校准图在巯基丙酸（MPA）修饰的电极两个数量级高于那些得到的共价结合。此外，介体四硫富瓦烯（TTF）与GOx一起共固定在SAM顶上。计算出TTF与MPA-GOx生物电极之间的非均相电子转移常数为1.25 s（-1）。对酶的负载量、电极上TTF的量、外加电位和pH进行了优化。TTF-GOx-MPA-AuE生物传感器具有良好的重复性，不需要对修饰电极进行预处理。当使用相同的生物传感器工作时，在5天后没有发现葡萄糖校准图的斜率值的显著变化。表观米氏常数为（13.9 +/- 0.5）mM，葡萄糖检测限为3.5 × 10（-6）M。此外，TTF-GOx-MPA-AuE在流动注射模式和真实的样品中的葡萄糖分析中也表现良好。(C)2002 Elsevier Science B. V.保留所有权利。
A critical study of the different variables affecting the preparation of enzyme electrochemical biosensors using self-assembled monolayer (SAM)-modified electrodes is reported. Regarding variables affecting the obtention of SAMs on a gold disk electrode (AuE), the type of alkanethiol employed, its concentration, the time and temperature of formation and the composition of the medium were evaluated. Concerning a glucose biosensor based on SAM-modified AuEs, the performances of several redox mediators for the enzymatic oxidation of glucose were compared. Two glucose oxidase (GOx) immobilization methods on the SAM-modified AuE were tested: a covalent binding using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysulfosuccinimide (NHSS), and a cross-linking with glutaraldehyde. The cross-linking method produced slopes of the substrate calibration graphs at a mercaptopropionic acid (MPA)-modified electrode two orders of magnitude higher than those obtained with the covalent binding. Moreover, the mediator tetrathiafulvalene (TTF) was co-immobilized atop the SAM together with GOx. A heterogeneous electron transfer constant between TTF and the MPA-GOx bioelectrode of 1.25 s(-1) was calculated. The enzyme loading, the amount of TTF on the electrode, the applied potential and the pH were also optimized. A good repeatability of the measurements with the TTF-GOx-MPA-AuE biosensor was demonstrated, with no need of pretreatment of the modified electrode. No significant changes in the slope value for the glucose calibration graph were found after 5 days when working with the same biosensor. An apparent Michaelis-Menten constant of (13.9 +/- 0.5) mM, and a limit of detection for glucose of 3.5 x 10(-6) M were obtained. Moreover, the TTF-GOx-MPA-AuE also performed well in the flow-injection mode and in the analysis of glucose in real samples. (C) 2002 Elsevier Science B.V. All rights reserved.