Because of serious toxic effects of mercury ion (Hg2+) on the environment and human body,it is of great significance to develop a simple and sensitive platform for Hg2+detection. Herein,a colorimetric biosensor with dual signal amplification principle based on catalytic hairpin assembly (CHA) and rolling circle amplification (RCA) was constructed for sensitive and selective detection of Hg2+. The presence of target Hg2+could initiate CHA reaction to form a double-stranded product via T-Hg2+-T base mismatch hybridization (First signal amplification). The double-stranded products could further trigger the RCA reaction to generate massive G-quadruplex sequences (Second signal amplification). These special DNA sequences had obvious horseradish peroxidase (HRP) mimicking activity after incubating with hemin,which could catalyze the conversion of colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) to form blue colored product. Because of the combination of two efficient signal amplification strategies,a low detection limit (0.21 nmol/L,3σ) was obtained by ultraviolet-visible absorption spectrometry. At the same time,the visual detection of Hg2+at concentration level of 1 nmol/L could be realized by observing the color of the solution with naked eyes. In addition,the proposed biosensor showed high specificity for detection of Hg2+,and could also be utilized to monitor Hg2+in real water samples. The sensing strategy provided a simple and sensitive platform for detection of heavy metal pollutants,showing great application potential in environmental monitoring.
关键词
催化发夹自组装/滚环扩增/生物传感器/可视化检测/汞离子
Key words
Catalytic hairpin assembly/Rolling circle amplification/Biosensor/Visual detection/Mercury ion
维普
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