Preparation of an enzymatic glucose sensor based on hybrid organic-inorganic Langmuir-Blodgett films : Adsorption of glucose oxidase into positively charged molecular layers
Preparation of an enzymatic glucose sensor based on hybrid organic-inorganic Langmuir-Blodgett films : Adsorption of glucose oxidase into positively charged molecular layers
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DOI：
10.1016/j.colsurfa.2008.02.032
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发表时间：
2008-05
期刊：
影响因子：
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通讯作者：
A. Kusakari;M. Izumi;H. Ohnuki
中科院分区：
文献类型：
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作者：
A. Kusakari;M. Izumi;H. Ohnuki
研究了葡萄糖氧化酶(GOx)在带正电的Langmuir-Blodgett(LB)膜上的吸附行为，探讨了其吸附机理。将葡萄糖氧化酶固定在由带正电的十八烷基三甲基铵(ODTA)和纳米普鲁士蓝(PB)簇合物组成的有机-无机复合膜中。这些ODTA/PB/Gox LB膜在0.0V(vs.Ag/AgCl)的极低工作电位下表现出葡萄糖传感器的作用，该电位已被确定为有效地抑制抗坏血酸和尿酸等干扰物的响应。我们研究了葡萄糖传感器的响应电流密度与GOx吸附溶液pH的函数关系。结果表明，电流密度强烈依赖于pH值。在接近GOx等电点的pH为4时，获得了最大电流密度，其值约为典型电流密度的4倍。红外吸收光谱表明，电流密度的这种依赖关系是由吸附的GOx的量与pH的关系引起的。基于GOX和ODTA之间静电引力的一系列模型可以很好地解释pH对GOX吸附的影响。这些发现有助于通过与带正电荷的分子的静电相互作用来固定Gox。
The adsorption of glucose oxidase (GOx) into positively charged Langmuir–Blodgett (LB) films has been studied to obtain an insight into the adsorption mechanism. Glucose oxidase was immobilized in hybrid organic–inorganic Langmuir–Blodgett films consisting of positively charged octadecyltrimethylammonium (ODTA) and nano-sized Prussian blue (PB) clusters. These ODTA/PB/GOx LB films showed a glucose sensor action at a very low operating potential of 0.0V (vs. Ag/AgCl), a potential which has been determined as being effective in inhibiting the responses from interferents such as ascorbic and uric acids. We investigated the response current density of the glucose sensor as a function of the pH of GOx adsorption solution. It was found that the current density depended strongly on the pH. The maximum current density, whose values were some four times greater than that of a typical current density for these systems, was obtained at pH 4, which is near the isoelectric point of GOx. Infrared absorption spectra revealed that such dependence of the current density was caused by the pH dependence of the amount of adsorbed GOx. A series of models based on the electrostatic attractive forces between GOx and ODTA can well explain the observed pH effect on the GOx adsorption. These findings are useful for immobilizing GOx through electrostatic interaction with positively charged molecules.