基于G-三链体DNA探针的汞离子检测新方法

A New Method for Mercury Ion Detection Based on G-triplex DNA Probe

开发简单快速的汞离子(Hg^(2+))检测新方法对人类了解重金属污染具有重要的意义.基于G-三链体DNA探针设计一种非标记的荧光方法用于汞离子检测.富含G碱基的DNA序列能自主装形成G-三链体结构.在没有Hg^(2+)存在的情况下,G-三链体DNA能与荧光染料硫黄素T结合生成非标记的荧光探针.硫黄素T与G-三链体结合后,ThT的荧光信号会显著增强.在Hg^(2+)存在的情况下,G-三链体DNA环部的胸腺嘧啶T能与Hg^(2+)发生反应,从而改变DNA的构型,抑制G-三链体结构的形成,使得ThT的荧光减弱.该方法通过对ThT-G-三链体的荧光强度变化实现溶液中的Hg^(2+)离子的检测.对该方法的可行性进行论证,并对实验条件进行优化.实验结果表明该方法可用于Hg^(2+)检测,并具有良好的灵敏度和选择性.

It is great significance to develop a simple and rapid method for the determination of mercury ion(Hg2+).In this paper,a novel biosensor was developed for Hg2+ion detection.This method is based on a label-free G-triplex DNA probe.The G-rich probe can self-assembled into a G-triplex structure.Herein,we found that the G-triplex can bind with fluorescent dye thioflavin T,leading to a high fluorescence enhancement of thioflavin T.However,in the presence of Hg2+ion,Hg2+ion influenced the formation of G-triplex structure and further inhibited the binding between thioflavin T and G-rich DNA probe,which resulting the fluorescence value of thioflavin T decreased.Based on the fluorescence signal change,the Hg2+ion can be detected in this new method.The feasibility of this method has been demonstrated,meanwhile,the experimental conditions were optimized.The experimental results show that this method exhibits a high sensitivity as well as good selectivity for Hg2+ion detection.