An aptasensing platform for simultaneous detection of multiple analytes based on the amplification of exonuclease-catalyzed target recycling and DNA concatemers

Analyst. 2013 Sep 7;138(17):4818-22. doi: 10.1039/c3an00757j. Epub 2013 Jul 1.

Abstract

In the present study, an ultrasensitive electrochemical aptasensor for the simultaneous detection of thrombin (TB) and ochratoxin A (OTA) was fabricated by using exonuclease-catalyzed target recycling and DNA concatemers for signal amplification. The previously hybridized double-stranded DNAs (SH-cTBA/TBA and SH-cOBA/OBA) were self-assembled on a gold electrode. In the presence of targets, the formation of aptamer-target complexes would lead to not only the dissociation of aptamers (TBA and OBA) from the double-stranded DNAs but also the transformation of the complementary DNAs (SH-cTBA and SH-cOBA) into hairpin structures. Subsequently, owing to employment of RecJf exonuclease, which is a single-stranded DNA-specific exonuclease to selectively digest the appointed DNAs (TBA and OBA), the targets could be liberated from the aptamer-target complexes for recycling of the analytes. Thereafter, probe DNAs (T1 and T2) were employed to hybridize with SH-cTBA and SH-cOBA respectively to provide primers for the concatemer reaction. After that, when four auxiliary DNA strands S1, anthraquinone-2-carboxylic acid (AQ)-labeled S2, S3, S4, as well as hemin were introduced, extended dsDNA polymers with lots of AQ moieties and hemin-G-quadruplex complexes could form on the electrode surface. Then, based on the signal of the AQ and hemin-G-quadruplex complex, an electrochemical aptasensor for the simultaneous detection of TB and OTA was successfully fabricated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aptamers, Nucleotide / metabolism*
  • Biocatalysis*
  • Biosensing Techniques / methods*
  • DNA / chemistry*
  • DNA / metabolism
  • Electrochemistry
  • Exodeoxyribonucleases / metabolism*
  • Ochratoxins / analysis*
  • Ochratoxins / metabolism
  • Thrombin / analysis*
  • Thrombin / metabolism
  • Time Factors

Substances

  • Aptamers, Nucleotide
  • Ochratoxins
  • ochratoxin A
  • DNA
  • Exodeoxyribonucleases
  • Thrombin