Real-time colorimetric detection of target DNA using isothermal target and signaling probe amplification and gold nanoparticle cross-linking assay

Cheulhee Jung, Ji Won Chung, Un Ok Kim, Min Hwan Kim, Hyun Gyu Park

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

We describe a facile gold nanoparticle (AuNP)-mediated colorimetric method for real-time detection of target DNA in conjugation with our unique isothermal target and signaling probe amplification (iTPA) method, comprising novel ICA (isothermal chain amplification) and CPT (cycling probe technology). Under isothermal conditions, the iTPA simultaneously amplifies the target and signaling probe through two displacement events induced by a combination of four specially designed primers, the strand displacement activity of DNA polymerase, and the RNA degrading activity of RNase H. The resulting target amplicons are hybridized with gold nanoparticle cross-linking assay (GCA) probes having a DNA-RNA-DNA chimeric form followed by RNA cleavage by RNase H in the CPT step. The intact GCA probes were designed to cross-link two sets of DNA-AuNPs conjugates in the absence of target DNA, inducing aggregation (blue color) of AuNPs. On the contrary, the presence of target DNA leads to cleavage of the GCA probes in proportion to the amount of amplified target DNA and the solution remains red in color without aggregation of AuNPs. Relying on this strategy, 102 copies of target Chlamydia trachomatis plasmid were successfully detected in a colorimetric manner. Importantly, all the procedures employed up to the final detection of the target DNA were performed under isothermal conditions without requiring any detection instruments. Therefore, this strategy would greatly benefit convenient, real-time monitoring technology of target DNA under restricted environments.

Original languageEnglish
Pages (from-to)1953-1958
Number of pages6
JournalBiosensors and Bioelectronics
Volume26
Issue number5
DOIs
Publication statusPublished - 2011 Jan 15
Externally publishedYes

Keywords

  • Colorimetric detection
  • GCA
  • Gold nanoparticles
  • ITPA
  • Nucleic acids

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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