铅离子诱导PS2.M构象改变特性及其氡非标记比色传感检测新方法

Pb^(2+)-Induced Allosteric PS2.M as A Label-Free Colorimetric Sensor for Detection of Cumulative Radon Radiation

以氡辐射衰变最终形成稳定的子体铅作为目标检测物,建立了检测氡累积浓度的核酸适配体生物分析新方法。K^+诱导富G单链核苷酸PS2.M形成反平行G-四链体四链体,辅因子血红素与G-四联链体结合,形成具有过氧化物酶活性的稳定复合物,催化TMB-H_2O_2体系发生显色反应。同时加入Pb^(2+)时,Pb^(2+)诱导PS2.M形成结构更加稳定的"缺口"型反平行G-四链体,K^+和血红素游离在溶液之中,体系吸光度响应值急剧降低。基于此构建了一种基于Pb^(2+)诱导PS2.M构象改变的过氧化物酶活性"Turn-off"型比色传感器。在5.0×10^(-9)~1.8×10^(-7)mol/L范围内,吸光度降低值ΔA与Pb^(2+)浓度呈线性关系,线性回归方程为ΔA=0.36+0.13C,R=0.9987。本方法对Pb^(2+)的检出限为3.76 nmol/L(S/N=3),氡的检出限为1.96×10~3Bq·h/m^3(S/N=3)。本方法灵敏、准确,样品溶液可直接检测,操作简单,避免了现场进行氡辐射剂量测量的放射性危害,为环境中氡的检测提供了新方法。

A new sensitive method for detection of cumulative radon radiation based on the lead was established.PS2.M which stabilized by K+with hemin as a co-factor exhibits superior peroxidase-like activity,and can effectively catalyze the H 2O 2-mediated oxidation of TMB.In the presence of Pb 2+,K+-stabilized PS2.M DNAzymes are induced to undergo a conformational change,because Pb 2+has a higher efficiency with regard to stabilizing G-quadruplexes than K+,accompanied by a decrease of catalytic activity and a sharp decrease of readout signal.In the work,a novel"turn-off"model of colorimetry-Pb 2+biosensor based on superior peroxidase-like activity of G-quadruplex for Pb 2+analysis was developed.The fading degree of reaction system(ΔA value)was linearly related to Pb 2+concentration in the range of 5.0×10 0x0E?Symbolm@@0x0F9-1.8×10 0x0E?Symbolm@@0x0F7 mol/L.The linear regression equation wasΔA=0.36+0.13 C(10 0x0E?Symbolm@@0x0F8 mol/L),with R=0.9987.The detection limits of lead and radon were 3.76 nmol/L(S/N=3)and 1.96×10 3 Bq·h/m 3(S/N=3),respectively.The method exhibited good selectivity,high sensitivity and convenient operation,and could avoid the radioactive hazard in determination of the radon in environment.