Electrochemical detection of DNA hybridization based on DNA-templated assembly of silver cluster

The growth of metals on DNA templates has generated considerable interest in connection to the design of metallic nanostructures. Here we exploit the DNA-induced generation of metal clusters for developing an electrical biosensing protocol. The new hybridization assay employs a probe-modified gold surface, and is based on the electrostatic 'collection' of silver cations along the DNA duplex, the reductive formation of silver nanoclusters along the DNA backbone, dissolution of the silver aggregate and stripping potentiometric detection of the dissolved silver at a thick-film carbon electrode. The new protocol thus combines the inherent signal amplification of stripping analysis with effective discrimination against nonhybridized DNA. (C) 2002 Elsevier Science B.V. All rights reserved.