基于铜纳米线放大的汞离子高灵敏比色检测法

Highly sensitive colorimetric assay for mercury ions based on copper nanowires amplification

将滚环扩增技术与铜纳米线相结合进行信号放大,建立高选择性、高灵敏的汞离子比色检测新方法。以链霉亲和素修饰的磁珠为探针捕获和分离基质,将生物素修饰的引物链固定到其表面。汞离子存在时,模板链将通过T-Hg^2+-T作用与引物链结合。加入T4连接酶及DNA聚合酶引发滚环扩增反应形成超长单链DNA。与短单链DNA互补形成的长双链DNA可作为铜纳米线沉积模板,加入盐酸释放出大量铜离子催化底物氧化显色。在0.005~1.0 nmol/L范围,汞离子浓度与吸收信号呈良好线性关系,检出限低至3.7 pmol/L。

By combining rolling circle amplification technology with copper nanowires for signal amplification,a novel colorimetric assay was established for highly selective and sensitive detection of mercury ions.Biotinmodified primer chains were immobilized on the surface of streptavidin-modified magnetic beads,which act as capture and separation substrates of probe.In the presence of mercury ions,template chains would bind to primer chains through T-Hg^2+-T interaction.T4 ligase and DNA polymerase were added to induce rolling circle amplification to form ultra-long single-stranded DNA.After hybridized with short single-stranded DNA,the formed long double-stranded DNA could be used as template for the deposition of copper nanowires.With the help of hydrochloric acid,large amount of copper ions would be released to catalyze the oxidation of substrates.In the range of 0.005-1.0 nmol/L,there was good linear relationship between the mercury ion concentration and the absorption signal,with the detection limit down to 3.7 pmol/L.