Electrodeposited gold–copper core–shell nanowires for high sensitivity DNA detection

Abstract

Gold–Copper core shell nanowires have been electrodeposited and their electrochemical and Raman properties probed. First, hollow copper nanotubes, 3.2 ± 0.1 μm long, with a uniform diameter of 70 ± 22 nm, were electrodeposited within the pores of a track etched polycarbonate membrane filter. Second, gold was then electrodeposited within these copper cylinders to yield the gold–copper core–shell nanowires. Nanowires, functionalised with probe strand DNA, that is complementary to that of the pathogen Staph. Aureus, only on their ends, can be immobilised onto an electrode surface in a DNA sandwich assay. Significantly, the charge associated with the selective oxidation of the copper shell depends linearly on the target DNA concentration from 1 nM to 100 μM.