Composite Assembly of Silver Nanoparticles with Avidin and Biotinylated AChE on Gold for the Pesticidal Electrochemical Sensing
Composite Assembly of Silver Nanoparticles with Avidin and Biotinylated AChE on Gold for the Pesticidal Electrochemical Sensing
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DOI：
10.1002/elan.200704060
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发表时间：
2008-02
期刊：
影响因子：
3
通讯作者：
Xi Huang;Dan Du;Xiaojuan Gong;Jie Cai;Haiyang Tu;Xing Xu;Aidong Zhang
中科院分区：
文献类型：
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作者：
Xi Huang;Dan Du;Xiaojuan Gong;Jie Cai;Haiyang Tu;Xing Xu;Aidong Zhang
将银纳米粒子与亲和素和生物素化乙酰胆碱酯酶（AChE）复合组装在以生物素为末端的自组装膜（SAM）修饰的金电极上，构建了电流型农药生物传感器。这种复合组装策略利用了生物特异性识别亲和素与SAM末端的生物素和生物素化的AChE，以及在pH 7.2下具有带负电荷的柠檬酸盐壳的银纳米颗粒与具有遭遇电荷的亲和素之间的静电相互作用。利用表面等离子体共振（SPR）技术监测了复合界面在金表面的形成过程，并利用衰减全反射傅里叶变换红外光谱、原子力显微镜和紫外-可见光谱对复合界面的结构进行了表征。通过循环伏安法和电化学阻抗谱表征了复合界面具有良好的电子传递能力。在最佳条件下，有机磷农药乐果的线性范围为0.05 μM ~ 10 μM，检测限为0.01 μM（信号衰减10%时的浓度）。银纳米粒子结合生物素-亲和素系统是一种简单、功能性的电极传感界面集成方法，具有良好的生物相容性和电子传递能力，可为生物电化学应用中的大量酶提供分析途径。
An amperometric pesticide biosensor has been devised by the composite assembly of silver nanoparticles with avidin and biotinylated acetylcholinesterase (AChE) on gold electrodes modified with a biotin-terminated self assembly monolayer (SAM). This composite assembly strategy takes use of the biospecific recognition avidin with the biotin from the SAM-terminals and biotinylated AChE, as well as the electrostatic interaction between silver nanoparticles with negatively charged citrate shell and avidin with encounter charge at pH 7.2. The construction process of the composite interface on gold was monitored by surface plasmon resonance (SPR), and its structure was characterized by attenuated total reflection Fourier-transform infrared spectra, atomic force microscopy and UV-vis spectra. The composite interface shows excellent electron transfer ability, as characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Under the optimum conditions a quantitative measurement of organophosphate pesticide dimethoate was achieved with the linear range of 0.05 μM to10 μM and the detection limit 0.01 μM, taken as the concentration equivalent to a 10% decrease in signal. Silver nanoparticles conjugated biotin-avidin system represents a simple and functional approach to the integration of electrode sensing interface with improved biocompatibility and electron transfer ability, which may provide an analytical access to a large group of enzymes for bioelectrochemical application.