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

Lee, H.J. and Li, Y. and Wark, Alastair and Corn, R.M. (2005) Enzymatically amplified SPR imaging detection of DNA by exonuclease III digestion of DNA microarrays. Analytical Chemistry, 77 (16). pp. 5096-5100. ISSN 0003-2700

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Abstract

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