基于DNA步行器信号放大的便携式传感器检测铅离子  

A Portable Sensor Based on DNA Walker Signal Amplification for Detection of Pb

作　　者：苏永欢 蔡杰 杨雅妮 刘冰倩 SU Yong-Huan;CAI Jie;YANG Ya-Ni;LIU Bing-Qian(Synthetic Pharmaceutical Engineering Laboratory of Guizhou Province,School of Pharmacy,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学药学院,贵州省合成药物工程实验室,贵阳550025

出　　处：《分析化学》2022年第4期525-534,共10页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(Nos.21864007,21605029);贵州省自然科学基金项目(Nos.黔科合基础[2020]1042,黔科合平台人才[2017]5788,黔科合平台人才[2018]5781)资助。

摘　　要：基于Pb^(2+)与底物链(Substrate DNA,sDNA)的特异性识别,以Fe_(3)O_(4)纳米磁珠(Fe_(3)O_(4)nano-magnetic beads,MB)为基底,便携式血糖仪(Portable glucose meter,PGM)为信号读出系统,利用DNA步行器放大信号,构建了一种灵敏且便捷的用于铅离子(Pb^(2+))检测的传感器。利用葡萄糖氧化酶(Glucose oxidase,GOx)和sDNA修饰还原法制备纳米金功能化的聚酰胺-胺型(Nanogold-functionalized poly(amidoamine),Au/PAMAM)树枝分子,形成sDNA/GOx/Au/PAMAM复合物;基于碱基互补配对原则,sDNA/GOx/Au/PAMAM复合物被固载于捕获链(Capture DNA,cDNA)修饰的MB(MB/cDNA)上,而DNA酶(DNAzyme)可与sDNA未碱基配对部分结合。当目标物存在时,Pb^(2+)可特异性识别s DNA上裂解位点并剪切,释放DNAzyme和GOx/Au/PAMAM。DNAzyme继续与sDNA/GOx/Au/PAMAM复合物上下一个sDNA配对结合,继而开启下一轮识别-剪切-释放,循环往复,形成DNA步行器,增加GOx/Au/PAMAM释放量,实现信号放大。反应体系中Pb^(2+)浓度越高,释放的GOx/Au/PAMAM量越多,通过磁性分离取上清液(GOx/Au/PAMAM)催化反应液中的葡萄糖(Glucose,Glu)氧化,使葡萄糖的浓度降低。用PGM测定Glu浓度,从而实现对Pb^(2+)浓度的间接测定。在最佳实验条件下,体系对PGM的响应值与Pb^(2+)浓度的对数呈反比,线性范围为1.00 pmol/L~1.00μmol/L,检出限为0.66 pmol/L。A sensitive and convenient sensor for detection of Pb^(2+)was established based on the specific recognition of Pb^(2+)and substrate DNA(sDNA),coupling with Fe_(3)O_(4)nano-magnetic beads(MB)as sensor platform,portable glucose meter(PGM)as signal capture terminal and DNA walking device as signal amplification strategy.The nanogold-functionalized Poly(amidoamine()Au/PAMAM)dendrimers prepared by reduction method were modified by glucose oxidase(GOx)and sDNA to form sDNA/GOx/Au/PAMAM complex.Based on the complementary base pairing principle,the sDNA/GOx/Au/PAMAM complex was captured on the MB modified by capture DNA(c DNA),and the DNA enzymes(DNAzyme)could bind to the un-paired parts of sDNA.In the presence of target,Pb^(2+)could specifically recognize cleavage sites on sDNA and shear it,meanwhile released DNAzyme and GOx/Au/PAMAM.The former continued to bind with the next sDNA,and then the new identification-split-release circulation was opened.The circulation could be called DNA walker device,and the release quantity of GOx/Au/PAMAM was increased to realize signal amplification.The supernatant(GOx/Au/PAMAM),separated by magnetic separation,could oxidize glucose(Glu)in the reaction solution,and the change value of Glu concentration was monitored with PGM,thus indirectly detecting the target Pb^(2+)concentration.Under the optimal conditions,the PGM response of the system showed a good linear relationship with the logarithm of Pb^(2+)concentration ranging from 1.00 pmol/L to 1.00μmol/L,and the detection limit was 0.66 pmol/L.

关 键 词：DNA步行器 信号放大 便携式血糖仪 铅离子 

分 类 号：X832[环境科学与工程—环境工程] TP212[自动化与计算机技术—检测技术与自动化装置]