Enzymatically amplified SPR imaging detection of DNA by exonuclease III digestion of DNA microarrays

H.J. Lee, Y. Li, Alastair Wark, R.M. Corn

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147 Citations (Scopus)


This paper describes a novel approach utilizing the enzyme exonuclease III in conjunction with 3‘-terminated DNA microarrays for the amplified detection of single-stranded DNA (ssDNA) with surface plasmon resonance (SPR) imaging. When ExoIII and target DNA are simultaneously introduced to a 3‘-terminated ssDNA microarray, hybridization adsorption of the target ssDNA leads to the direction-dependent ExoIII hydrolysis of probe ssDNA strands and the release of the intact target ssDNA back into the solution. Readsorption of the target ssDNA to another probe creates a repeated hydrolysis process that results over time in a significant negative change in SPR imaging signal. Experiments are presented that demonstrate the direction-dependent surface enzyme reaction of ExoIII with double-stranded DNA as well as this new enzymatically amplified SPR imaging process with a 16-mer target ssDNA detection limit of 10−100 pM. This is a 102−103 improvement on previously reported measurements of SPR imaging detection of ssDNA based solely on hybridization adsorption without enzymatic amplification
Original languageEnglish
Pages (from-to)5096-5100
Number of pages5
JournalAnalytical Chemistry
Issue number16
Early online date30 Jun 2005
Publication statusPublished - 2005


  • exonuclease
  • enzymatically amplified
  • SPR imaging detection
  • DNA
  • digestion
  • dna microarrays


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