基于核酸适配体9335构象变化的比色传感新方法检测水中铅

A new method based on the allosteric of 9335 as a colorimetric sensor for detection of lead in water

目的建立一种新颖的基于铅离子诱导富含鸟嘌呤寡核苷序列构象改变的核酸适配体比色传感检测平台,实现环境水样中铅离子的超灵敏检测。方法铅离子诱导富含鸟嘌呤的核酸适配体链形成G-四链体构象,可结合氯化血红素,形成具备过氧化物酶活性的复合物,催化四甲基联苯胺-过氧化氢系统氧化显色。基于此建立一种铅离子诱导9335构象变换的过氧化物酶活性“turn-on”型比色传感器,通过紫外可见分光光度法实现铅的超灵敏检测。结果在9.18 ng/L~100 ng/L内,吸光度差值ΔA与铅离子浓度(c)具有良好的线性关系,线性回归方程为ΔA=0.1006+0.0098c,r=0.9996,铅离子的检出限为2.84 ng/L。结论新方法可特异地检测水样中微量铅离子,方法具有良好的灵敏度,简便可行且环保,可用于环境水样中微量铅离子的检测。

Objective A novel aptamer colorimetric sensing platform based on G-rich DNA sequences stabilized by Pb2+was established for ultra-sensitive detection of Pb2+in water.Methods G-rich aptamer stabilized by Pb2+with hemin as a co-factor exhibits peroxidase-like activity,and can effectively catalyze the H2O2-mediated oxidation of TMB.In this work,a“turn-on”type of colorimetric biosensor based on peroxidase activity of G-quadruplex was established for ultra-sensitive detection of Pb2+by UV-visible spectrophotometry.Results The fading degree of reaction system(ΔA)was linearly related to lead concentration(c)in the range of 9.18 ng/L-100 ng/L.The linear regression equation wasΔA=0.1006+0.0098c,(r=0.9996).The detection limit was 2.84 ng/L.Conclusion The method has strong sensitivity and good selectivity.The method is simple,feasible,and environmentally friendly,which can be applied in ultra-sensitive detection of lead in water.