Engineering Laboratory for Modern Analytical Techniques, c/o State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
Biosens Bioelectron. 2011 Jul 15;26(11):4355-61. doi: 10.1016/j.bios.2011.04.037. Epub 2011 Apr 29.
Sensitive electrochemical impedance assay of DNA hybridization by using a novel graphene sheets platform was achieved. The graphene sheets were firstly functionalized with 3,4,9,10-perylene tetracarboxylic acid (PTCA). PTCA molecules separated graphene sheets efficiently and introduced more negatively-charged -COOH sites, both of which were beneficial to the decoration of graphene with gold nanoparticles. Then amine-terminated ionic liquid (NH₂-IL) was applied to the reduction of HAuCl₄ to gold nanoparticles. The green-synthesized gold nanoparticles, with the mean diameter of 3 nm, dispersed uniformly on graphene sheets and its outer layer was positively charged imidazole termini. Due to the presence of large graphene sheets and NH₂-IL protected gold nanoparticles, DNA probes could be immobilized via electrostatic interaction and adsorption effect. Electrochemical impedance value increased after DNA probes immobilization and hybridization, which was adopted as the signal for label-free DNA hybridization detection. Unlike previously anchoring DNA to gold nanoparticles, this label-free method was simple and noninvasive. The conserved sequence of the pol gene of human immunodeficiency virus 1 was satisfactorily detected via this strategy.
通过使用新型石墨烯片平台，实现了对 DNA 杂交的敏感电化学阻抗分析。首先用 3,4,9,10-苝四羧酸（PTCA）对石墨烯片进行功能化。PTCA 分子有效地分离石墨烯片并引入更多带负电荷的 -COOH 位点，这两者都有利于金纳米粒子在石墨烯上的修饰。然后，将末端为胺的离子液体（NH₂-IL）应用于 HAuCl₄还原为金纳米粒子。绿色合成的金纳米粒子，平均直径为 3nm，均匀分散在石墨烯片上，其外层带正电荷的为咪唑端基。由于存在大的石墨烯片和 NH₂-IL 保护的金纳米粒子，DNA 探针可以通过静电相互作用和吸附作用固定。DNA 探针固定和杂交后，电化学阻抗值增加，可作为无标记 DNA 杂交检测的信号。与以前将 DNA 锚定在金纳米粒子上的方法不同，这种无标记方法简单且非侵入性。通过该策略可以满意地检测到人类免疫缺陷病毒 1 的 pol 基因的保守序列。
