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Colorimetric ultrasensitive detection of DNA based on intensity of gold nanoparticles with dark-field microscopy

Abstract

We present an ultrasensitive colorimetric nucleic acid assay based on intensity of gold nanoparticles (Au NPs) by dark field microscopy. In the absence of target DNA, two hairpin-like DNA strands with protrudent single-stranded DNA (ssDNA) can be absorbed on Au NP surface via non-covalent interactions between the exposed nitrogen bases of ssDNA and Au NPs, which inhibits Au NPs from aggregation in high concentration of salt media. While in the presence of target DNA, two hairpin DNA strands hybridize with target DNA to form double-stranded DNA (dsDNA). After hybridization chain reaction (HCR) amplification, rigid dsDNA polymers are formed, which results in serious Au NP aggregation in the salt environment. By measuring the intensity change of yellow and red dots on a dark-field image, the concentration of target DNA can be accurately quantified with limit of detection (LOD) of 66 fM.

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Publication details

The article was received on 03 May 2018, accepted on 11 Jul 2018 and first published on 12 Jul 2018


Article type: Paper
DOI: 10.1039/C8AN00825F
Citation: Analyst, 2018, Accepted Manuscript
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    Colorimetric ultrasensitive detection of DNA based on intensity of gold nanoparticles with dark-field microscopy

    Z. Chen, J. Li, C. Kong and Q. Liu, Analyst, 2018, Accepted Manuscript , DOI: 10.1039/C8AN00825F

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