Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education of China, Shandong University, Jinan 250100, PR China.
Colloids Surf B Biointerfaces. 2010 Aug 1;79(1):304-8. doi: 10.1016/j.colsurfb.2010.04.017. Epub 2010 Apr 24.
An attempt was made in the present paper to develop a nanoporous gold (NPG)-based electrochemical aptasensor for thrombin detection. The substrate electrode NPG was in situ fabricated by a facile one-step square wave potential pulse (SWPP) treatment. The treatment involved repeated gold oxidation-reduction and intensive H(2) bubbles evolution. After 100min treatment, the active surface area of Au increased greatly (34 times). The electrochemical aptasensor was fabricated using a layer-by-layer assembling strategy. A "sandwich" structure was formed via thrombin connecting the aptamer-modified NPG and the aptamer-modified Au nanoparticles (AuNPs). The AuNPs was modified with two kinds of single strand DNA (ssDNA). One was aptamer of thrombin, but the other was not, reducing the cross-reaction between thrombin and its aptamer on the same AuNP. The electrochemical signal produced by the Ru(NH(3))(6) bound to ssDNA via electrostatic interaction was measured by chronocoulometry. Due to the amplification effects of both NPG and AuNPs, this novel NPG-based aptasensor could detect thrombin quantitatively in the range of 0.01-22nM with a detection limit as low as 30fM. The present aptasensor also exhibited excellent selectivity, stability and reusability.
本研究旨在开发一种基于纳米多孔金（NPG）的电化学适体传感器用于检测凝血酶。通过简便的方波电位脉冲（SWPP）处理原位合成 NPG 基底电极。该处理涉及重复的金氧化还原和剧烈的 H(2)气泡演化。经过 100min 的处理，Au 的有效表面积大大增加（34 倍）。通过层层组装策略制备电化学适体传感器。通过凝血酶连接适体修饰的 NPG 和适体修饰的金纳米粒子（AuNPs）形成“三明治”结构。AuNPs 修饰有两种单链 DNA（ssDNA）。一种是凝血酶的适体，但另一种不是，这减少了同一 AuNP 上凝血酶与其适体之间的交叉反应。通过计时库仑法测量通过静电相互作用与 ssDNA 结合的Ru(NH(3))(6)产生的电化学信号。由于 NPG 和 AuNPs 的放大效应，这种新型基于 NPG 的适体传感器能够在 0.01-22nM 的范围内定量检测凝血酶，检测限低至 30fM。该适体传感器还表现出优异的选择性、稳定性和可重复性。
