Double amplified colorimetric detection of DNA using gold nanoparticles, enzymes and a catalytic hairpin assembly

Chanho Park, Hyunjun Park, Hye Jin Lee, Hye Sun Lee, Kyong Hwa Park, Chang Hwan Choi, Sungsoo Na

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


The authors describe an isothermal and ultrasensitive colorimetric DNA assay that consists of two amplification stages using enzymes and a catalytic hairpin assembly (CHA). The first step consists in the selective amplification of DNA using Klenow fragment and nicking enzyme. The second step consists in the amplification of the optical signal by using a catalytic hairpin assembly. After two amplification steps, the DNA reaction induces the aggregation of the red gold nanoparticles to give a blue color shift. The degree of aggregation can be quantified by measurement of the ratio of the UV-vis absorbances of the solutions at 620 and 524 nm which are the wavelengths of the aggregated gold nanoparticles and bare gold nanoparticles. The detection limit is as low as 3.1 fM. Due to the use of a specific enzyme, only the desired DNAs will be detected. The method can be applied to the determination of DNA of various lengths. Despite the presence of large amounts of wildtype DNA, it can readily detect a target DNA. Conceivably, the technique has a large potential because of its high sensitivity and selectivity. [Figure not available: see fulltext.].

Original languageEnglish
Article number34
JournalMicrochimica Acta
Issue number1
Publication statusPublished - 2019 Jan 1

Bibliographical note

Publisher Copyright:
© 2018, Springer-Verlag GmbH Austria, part of Springer Nature.


  • AuNPs
  • CHA
  • DNA sensor
  • Hairpin DNA
  • Klenow fragment
  • Liquid biopsy
  • UV-vis absorbance

ASJC Scopus subject areas

  • Analytical Chemistry


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