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- Title
Ultrasensitive colorimetric strategy for Hg<sup>2+</sup> detection based on T-Hg<sup>2+</sup>-T configuration and target recycling amplification.
- Authors
Sang, Fuming; Yin, Suyao; Pan, Jianxin; Zhang, Zhizhou
- Abstract
A novelty aptasensor for ultrasensitive detection of Hg2+ is developed, exploiting the combination of plasmonic properties of gold nanoparticles (AuNPs) and exonuclease III (Exo III)-assisted target recycling for signal amplification. In the presence of Hg2+, a DNA duplex can be formed due to the strong coordination of Hg2+ and T bases of single-stranded DNA (ssDNA) probe. Exo III digests the DNA duplex from the 3′ to 5′ direction, resulting in the releasing of Hg2+. Then, the released Hg2+ binds with another ssDNA probe through T-Hg2+-T coordination. After Exo III-assisted Hg2+ cycles, numerous ssDNA probes are exhausted, which promotes poly(diallyldimethylammonium chloride) (PDDA)-induced AuNP aggregation, leading to an obvious color change and aggregation-induced plasmon red shift of AuNPs (from 520 to 610 nm). Therefore, this biosensor is ultrasensitive, which is applicable to the detection of trace level of Hg2+ with a linear range from 5 pM to 0.6 nM and an ultralow detection limit of 0.2 pM. Furthermore, it enables visual detection of Hg2+ as low as 50 pM by the naked eye. More importantly, the assay can be applied to the reliable determination of spiked Hg2+ in sea water samples with good recovery.
- Subjects
EXONUCLEASES; SINGLE-stranded DNA; GOLD nanoparticles; SEAWATER; REDSHIFT; PLASMONICS; DETECTION limit
- Publication
Analytical & Bioanalytical Chemistry, 2021, Vol 413, Issue 28, p7001
- ISSN
1618-2642
- Publication type
Article
- DOI
10.1007/s00216-021-03657-1