基于等离子激元耦合效应的高灵敏汞离子传感器  

Highly Sensitive Detection of Mercury Ion Based on Plasmon Coupling

作　　者：钱广盛 赵微 徐静娟 陈洪渊 

机构地区：[1]南京大学化学化工学院生命分析化学国家重点实验室,南京210023

出　　处：《化学学报》2017年第11期1097-1102,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.21327902;21535003)资助~~

摘　　要：提出了一种基于单颗粒光谱技术,能够高灵敏检测汞离子的新方法,原理是基于汞离子诱导的纳米金自组装过程.在两种不同大小的纳米金表面分别修饰两段富含T碱基的DNA序列,当Hg^(2+)存在时,两段DNA序列自发形成双链结构,导致小金球能够在大金球表面自组装成核-卫星纳米金结构,这一过程伴随着纳米颗粒散射光颜色和散射峰位置的变化,变化的程度与Hg^(2+)浓度具有相关性,依托单颗粒光谱技术极高的检测灵敏度,该方法可以实现pmol/L级的检测.Mercury is very harmful to the environment and human health even at low concentration. Methods for sensitive detection of mercury ion（Hg^（2＋）） have increasingly been developed over the past decade owing to the rapid development in nanotechnology. However, the limits of detection（LODs） of these methods are mostly not satisfactory enough to meet the demand of monitoring trace amounts of mercury ion. DNA thymine（T bases） can react with the mercury ion to form T-Hg^（2＋）-T structure, and this interaction has been proved to be much more stable than the interaction between thymine and its complementary adenine（A bases）. Based on this principle, a series of ultra-sensitive DNA-based colorimetric biosensors, mostly using Au nanoparticles（Au NPs） as DNA carriers, have been designed for detection of mercury ion. In this study, we report a new strategy for highly sensitive Hg^（2＋） detection based on Hg^（2＋）-induced Au NPs assembly. Au NPs of different sizes（s-Au NPs of 18 nm and c-Au NPs of 52 nm） were modified with oligonucleotides containing a sequence of continuous T bases. In the presence of Hg^（2＋）, s-Au NPs would be bound to c-Au NPs in the solution owing to oligonucleotide hybridization, forming a core-satellites nanostrucure. This process was accompanied by a color change of the scattering light from green to orange as observed under dark-field microscopy and a corresponding distinct scattering peak shift. The scattering spectra of the Au NPs were obtained using a spectroscopic system which was established autonomously. The scattering peak shift of color-changed spots corresponded with Hg^（2＋） concentration. It was increased linearly with logarithm of Hg^（2＋）concentration over a wide range from 1 pmol/L to 1 nmol/L, with the correlation coefficient of 0.983（R2=0.983）, and the detection limit of Hg^（2＋） was estimated to be 1 pmol/L. Other metal ions, such as Ag＋, K＋, Ca^（2＋）, Mg^（2＋）, Zn^（2＋）, Cd^（2＋）, Fe^（2＋）

关 键 词：汞离子 纳米自组装 T-Hg2+-T 等离子激元耦合 

分 类 号：O657.3[理学—分析化学] TP212[理学—化学]