Development of a gold-nanostructured surface for amperometric genosensors

A gold nanostructured surface has been obtained by stable deposition of chemically synthesized gold nanoparticles on a gold substrate, through a dithiol linker. The method proposed for the obtainment of the nanostructure results suitable for the further stable anchoring of peptide nucleic acids (PNA) through four amines from lysine terminal residues, leading to fairly reproducible systems. The geometric area of the nanostructured surface is compared with those of a smooth and of an electrochemical generated nanostructured surface, by depositing a probe bearing an electrochemically active ferrocene residue. Despite the area of the two nanostructures results quite similar, the response toward 2 nM target oligonucleotide sequence is particularly high when using the surface built up by nanoparticles deposition. This aspect indicates that morphologic details of the nanostructure play a key role in conditioning the performances of the genosensors