Publication 541

Contribution from the Laboratoire de Microbiologie Médicale et Moléculaire, Faculté de Médecine et de Pharmacie, 7 Boulevard Jeanne d'Arc, 21033 Dijon, France and the Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche Université - CNRS No 7591, Université de Paris 7 - Denis Diderot, 2 place Jussieu, 75251 Paris Cedex 05, France

An electrochemical DNA detection method has been developed for the sensitive quantification of an amplified 406-base pair human cytomegalovirus DNA sequence (HCMV DNA). The assay relies on (i) the hybridization of the single-stranded target HCMV DNA with an oligonucleotide-modified Au nanoparticle probe, (ii) followed by the release of the gold metal atoms anchored on the hybrids by oxidative metal dissolution, and (iii) the indirect determination of the solubilized Au^III ions by anodic stripping voltammetry at a sandwich-type screen-printed microband electrode (SPMBE). Due to the enhancement of the Au^III mass transfer by nonlinear diffusion during the electrodeposition time, the SPMBE allows the sensitive determination of Au^III in a small volume of quiescent solution. The combination of the sensitive Au^III determination at a SPMBE with the large number of Au^III released from each gold nanoparticle probe allows detection of as low as 5 pM amplified HCMV DNA fragment.