基于金纳米聚集-核酸适配体传感光度法检测铅

Spectrophotometric detection of lead ions based on gold nano-aggregation nucleic acid adaptor sensor

目的基于核酸适配体修饰的AuNPs与阳离子染料MG之间相互作用,以核酸适配体为识别元件,实现对Pb^(2+)高选择性的识别;选用AuNPs及MG作为探针元件,构建快速检测Pb^(2+)的新型核酸适配体生物比色传感器。方法以柠檬酸三钠为热稳定剂和还原剂制备AuNPs,将核酸适配体PW17吸附在纳米金颗粒表面。当体系中存在Pb^(2+)时,核酸适配体PW17能够被Pb^(2+)特异性地诱导变构形成G-四链体结构,游离的AuNPs在MG作用下发生聚集,反应体系颜色发生变化。结果在最优实验条件下,在0.25μmol/L-10μmol/L内,ΔA_(617/520)与Pb^(2+)浓度呈良好的线性关系,其线性回归方程为ΔA_(617/520)=0.072 C_(Pb)(×10^(-6)mol/L)-0.0267,r=0.997,该方法的检出限为0.17μmol/L。结论本研究富G序列的核酸适配体PW17能够与纳米金颗粒发生静电作用,拓展其发展成为一种新颖的核酸适配体传感器检测平台;该方法具有良好灵敏度,线性范围宽,应用前景良好可观。

Objective This paper puts forward a method based on the interaction between AuNPs modified with nucleic acid aptamers and cationic dye MG.We constructed a novel colorimetric sensor for rapidly detecting Pb^(2+)by using nucleic acid aptamers as recognition elements to achieve high selectivity recognition of Pb^(2+)when AuNPs and MG are as colorimetric probes.Methods Gold nanoparticles(AuNPs)were prepared by trisodium citrate which is acted as deoxidizer and heat stabilizer and AuNPs are protected by adapters.When Pb^(2+)is present in the system,Pb^(2+)can specifically induce the aptamer PW17 to a G-quadruplex structure,and the free AuNPs aggregate under the action of the cationic dye malachite green(MG),causing the color change of the reaction system.Results Under the best experimental conditions,there was a linear correlation between Pb^(2+)andΔA_(617/520)in the range of 0.25 μmol/L-10μmol/L.The linear regression equation wasΔA_(617/520)=0.072 c_(Pb)(×10^(-6)mol/L)-0.0267,r=0.997.The detection limit is 0.17 μmol/L.Conclusion The nucleic acid aptamer PW17 of the G-rich sequence can electrostatically interact with the gold nanoparticles,so it is available to develop this method into a novel metal ion nucleic acid aptamer sensor detection platform.This method has strong sensitivity and excellent selectivity.The linear range is wide.The application prospect of this strategy in biosensors is promising.