基于G-四链体-血红素DNAzyme介导金纳米棒蚀刻可视化定量检测铅离子  

Visual and Quantitative Detection of Lead Ion Based on G-quadruplex-hemin DNAzyme-mediated Etching of Gold Nanorods

作　　者：王君旸 段子璇 吴同 王蔚 孙春燕 WANG Jun-Yang;DUAN Zi-Xuan;WU Tong;WANG Wei;SUN Chun-Yan(College of Food Science and Engineering,Jilin University,Changchun 130062,China)

机构地区：[1]吉林大学食品科学与工程学院,长春130062

出　　处：《分析化学》2022年第10期1473-1481,共9页Chinese Journal of Analytical Chemistry

基　　金：吉林大学“大学生创新创业训练计划”创新训练项目(No.202110183164)资助。

摘　　要：基于G-四链体-血红素(Hemin)DNAzyme介导金纳米棒(AuNRs)蚀刻构建了一种无标记可视化的铅离子(Pb^(2+))生物传感器。血红素可诱导核酸适配体PS2.M转变为G-四链体结构,生成具有类过氧化物酶活性的G-四链体-Hemin DNAzyme,催化H_(2)O_(2)氧化3,3′,5,5′-四甲基联苯胺(TMB)生成蓝色的二亚胺衍生物TMB^(+),加入H_(2)SO_(4)终止酶促反应,TMB^(+)变成TMB^(2+)(亮黄色)。在十六烷基三甲基溴化铵(CTAB)作用下,TMB^(2+)可以有效地将Au(0)氧化成Au(Ⅰ),从而实现AuNRs的蚀刻,溶液呈黄色。当目标物Pb^(2+)存在时,由于Pb^(2+)与其核酸适配体的高特异性相互作用,以及Pb^(2+)稳定G-四链体的能力显著强于血红素,而无法形成具有类酶活性的G-四链体-Hemin DNAzyme,从而不能蚀刻AuNRs。因此,Pb^(2+)的存在使整个检测系统产生鲜明的颜色变化,可以方便的用裸眼辨别。通过测定AuNRs纵向表面等离子吸收峰的吸收值与450 nm处TMB^(2+)吸收峰的吸收值,可实现对Pb^(2+)的比率型定量检测,线性范围为5~5000 nmol/L,检出限(3σ)低至2.0 nmol/L。将本方法用于松花江水和自来水样品中Pb^(2+)的检测,加标回收率分别为98.7%~102.5%和94.8%~108.2%,与电感耦合等离子体质谱法(ICP-MS)检测结果一致。A label-free visualized lead ion biosensor was constructed based on G-quadruplex-hemin DNAzyme-mediated etching of gold nanorods(AuNRs).Hemin could induce the transformation of the aptamer PS2.M into a G-quadruplex structure to generate a G-quadruplex-hemin DNAzyme with peroxidase-like activity.3,3′,5,5′-Tetramethylbenzidine(TMB)was oxidized to form a blue diimine derivative TMB^(+),and the enzymatic reaction was terminated after adding H_(2)SO_(4),and TMB^(+)became TMB^(2+)(yellow).Under the action of hexadecyl trimethyl ammonium bromide(CTAB),TMB^(2+)could effectively oxidize Au(0)to Au(Ⅰ),thereby realizing the etching of AuNRs,and the solution turned yellow.Due to the highly specific interaction between PS2.M and Pb^(2+),and the ability of Pb^(2+)to stabilize G-quadruplexes was significantly stronger than that of hemin,G-quadruplexes-hemin DNAzyme with enzyme-like activity could not be formed in the presence of Pb^(2+),thus unable to etch AuNRs.Therefore,different concentrations of Pb^(2+)made the solutions produce distinct color changes that could be easily identified with naked eyes.The ratiometric quantitative detection of Pb^(2+)was achieved by measuring the absorbance of the longitudinal surface plasmon absorption peak of AuNRs and the TMB^(+)absorption peak at 450 nm,with a linear range of 5-5000 nmol/L and a detection limit as low as 2.0 nmol/L.The method was successfully applied to detection of Pb^(2+)in Songhua River water and tap water samples,with spiked recoveries were 98.7%-102.5%and 94.8%-108.2%,respectively,and the results were consistent with the detection results of inductively coupled plasma-mass spectrometry(ICP-MS).The method ingeniously designed the nucleic acid sequence,and realized the rapid and high-sensitivity visual detection of Pb^(2+).

关 键 词：核酸适配体 G-四链体-血红素DNAzyme 铅离子 金纳米棒 可视化 

分 类 号：O657.3[理学—分析化学]