Silver-enhanced colloidal gold electrochemical stripping detection of DNA hybridization

We report on a novel method for detecting DNA hybridization, based on the p recipitation of silver on gold nanoparticle tags and a subsequent electroch emical stripping detection of the dissolved silver. Such coupling of a nano particle-promoted silver precipitation with the remarkable sensitivity of s tripping metal analysis offers a dramatic enhancement of the hybridization response. An efficient magnetic isolation of the duplex is used for discrim inating against nonhybridized DNA, including an excess of mismatched oligon ucleotides. The new silver-enhanced colloidal gold stripping detection stra tegy holds great promise for the detection of DNA hybridization and represe nts an attractive alternative to indirect optical affinity assays of nuclei c acids and other biomolecules.