Preparation of ferrocene-functionalized gold nanoparticles by primer extension reaction on the particle surface.

DNA molecules possessing multiple ferrocene (Fc) molecules as a redox active probe were prepared by the primer extension (PEX) reaction using a 2'-deoxyuridine-5'-triphosphate derivative in which Fc was connected to the C5-position of the uridine by a diethylene glycol linker. Gold nanoparticles (AuNP) covered with DNA possessing the Fc molecules were prepared by the PEX reaction on the surface. The AuNP-FcDNA conjugates exhibit a detectable electrochemical signal due to the Fc molecules. Possible application of the PEX reaction on AuNP is demonstrated for the detection of a single nucleotide mutation in the target DNA.