Selective glucose detection based on the concept of electrochemical depletion of electroactive species in diffusion layer.
Selective glucose detection based on the concept of electrochemical depletion of electroactive species in diffusion layer.
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DOI：
10.1016/j.bios.2004.05.009
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发表时间：
2005-01
影响因子：
12.6
通讯作者：
Kang Wang;Jingjuan Xu;Da-Cheng Sun;Hui Wei;X. Xia
中科院分区：
文献类型：
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作者：
Kang Wang;Jingjuan Xu;Da-Cheng Sun;Hui Wei;X. Xia
利用扫描电化学显微镜（SECM）建立了一种基于扩散层电活性物种电化学耗尽概念的葡萄糖检测方法。通过将葡萄糖氧化酶（GOD）修饰电极（基底电极）控制在干扰电活性物质的电化学氧化的适当电位，即，抗坏血酸（AA），在基板电极的扩散层中形成无干扰的微环境。因此，我们可以通过将Pt超微电极（UME）（尖端电极，半径为5μm）置于基底电极的扩散层中来成功地检测酶促反应产生的过氧化氢。系统地研究了这种基于电化学耗尽的干扰消除方法的特性。结果表明，探针与基底间的距离和基底电位对干扰去除效率有显著影响。当针尖-基底距离为11μm（电极半径的2.2倍），基底电位为0.5V时，在30 s内可以去除近90%的AA（0.5mM）而不消耗H_2O_2。在此条件下，0.1mM AA对0.5mM葡萄糖的检测无影响。葡萄糖检测的线性范围为0.01- 1 mM，检测限（DL）为0.005mM（相关系数为0.9948）。该研究为研制选择性微生物传感器开辟了一条新的途径。
A glucose detection approach based on the concept of electrochemical depletion of electroactive species in diffusion layer was established, using scanning electrochemical microscopy (SECM). By controlling the glucose oxidase (GOD) modified electrode (substrate electrode) at a proper potential of electrochemical oxidation of interfering electroactive species, i.e., ascorbic acid (AA), an interference-free microcircumstance was formed in the diffusion layer of the substrate electrode. Consequently, we could successfully sense hydrogen peroxide generated from an enzymatic reaction by locating a Pt ultramicroelectrode (UME) (tip electrode, 5μm in radius) into the diffusion layer of the substrate electrode. Properties of this interference-removing approach based on electrochemical depletion were systematically investigated. Results showed that the interference-removing efficiency was significantly determined by the tip-substrate distance and substrate potential. When the tip-substrate distance was 11μm (2.2 times of the tip electrode radius) and the substrate potential was 0.5V, nearly 90% of AA (0.5mM) could be depleted within 30s without consumption of H2O2. Under these conditions, 0.1mM AA showed no influence on the detection of 0.5mM glucose. The linear range of glucose detection is 0.01–1mM with a detection limit (DL) of 0.005mM (correlation coefficient is 0.9948). This research will open a new way for developing selective micro-biosensors.