Selectivity and sensitivity of a reagentless electrochemical DNA sensor studied by square wave voltammetry and fluorescence

Bioelectrochemistry. 2006 Oct;69(2):172-9. doi: 10.1016/j.bioelechem.2005.12.007. Epub 2006 Mar 6.

Abstract

Poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone)-modified electrode is used for the direct electrochemical detection of oligonucleotide hybridization. The polymer film presents well-defined electroactivity in the cathodic potential domain (between 0 and -0.8 V/SCE), due to the quinone group embedded into the polymer structure. The detection can be performed simply by square wave voltammetry. This sensor is a "signal-on" device and works with different oligonucleotide lengths, from 10 to 30 bases. Quantitative results from fluorescence are consistent with electrochemical data. It is confirmed that the signal increase in square wave voltammetry is unambiguously due to hybridization. The biosensor presents a detection limit of target of ca. 25 nM and is highly selective as it can discriminate single mismatch base.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosensing Techniques / instrumentation*
  • Biosensing Techniques / methods
  • DNA / analysis*
  • DNA / chemistry*
  • Electrochemistry / instrumentation*
  • Electrochemistry / methods
  • Equipment Design
  • Equipment Failure Analysis
  • In Situ Hybridization, Fluorescence / instrumentation*
  • Indicators and Reagents
  • Oligonucleotide Array Sequence Analysis / instrumentation*
  • Oligonucleotide Array Sequence Analysis / methods
  • Reproducibility of Results
  • Sensitivity and Specificity

Substances

  • Indicators and Reagents
  • DNA