基于核酸适配体与金纳米粒子检测水中Hg^(2+)的研究

Colorimetric biosensing of Mercury(Ⅱ) ion using the novel aptamer modified gold nanoparticles as a probe

基于Hg2+与胸腺嘧啶(T)的T-T错配结合的特性,构建出一种快速便捷的可在高盐溶液中诱导金纳米粒子可控聚集的比色检测Hg2+的方法。采用硼氢化钠还原法制备金纳米粒子,并应用透射电子显微镜和紫外分光光度计对其进行表征。设计核酸适配体并修饰金纳米粒子表面,增强金纳米粒子的稳定性,使其能够拮抗高盐诱导下的团聚行为,当存在Hg2+时,核酸适配体与Hg2+结合,使得金粒子去保护而聚集,产生了颜色的变化,从而通过比色法定量分析Hg2+的浓度。结果表明,以硼氢化钠为还原剂可以得到稳定性好且分布均匀的平均粒径约为27nm的金纳米粒子;伴随Hg2+浓度的提高,体系颜色由红色向蓝色发生转变;荧光光谱结果表明,伴随Hg2+浓度的提高,荧光强度逐渐增强;说明金纳米粒子逐步发生团聚;检测体系对8种常见离子具有明显的选择检测性能。

A simple and rapid colorimetric method was developed for the detection of Hg2＋based on the specific thymine T-Hg2＋-T structure and gold nanoparticles（Au NPs） in the presence of a given high concentration of salt. The gold nanoparticles were prepared by the Na BH4 reduction method. Transmission electron microscopy,laser particles size analyzer,and UV-vis spectroscopy were used to characterize the samples. The aptamer was designed to attach to Au NPs and effectively prevent Au NPs from salt induced aggregation. While the presence of Hg2＋ions,the Au NPs were less well-protected thus aggregated at the salt concentration,resulting into a color change. It could be colorimetric quantitative analysis of the concentration of Hg2 ＋. The results showed that the product with good stability and good distribution could be obtained with taking sodium borohydride as reductant Au NPs had a mean diameter of 27 nm. It was observed that the aptamer-stabilized Au NPs solution showed a color change from red- to- blue when Hg2 ＋was added into the solution. The aptamer- Au NPs exhibited strong fluorescence emission, while upon addition Hg2 ＋, the solution showed a dramatic increase of the fluorescence intensity as a result of the aggregation behavior of the Au NPs. The paper based sensor showed high selectivity for 8 kinds of metal ions.