Tunnelling current recognition through core–satellite gold nanoparticles for ultrasensitive detection of copper ions

Abstract

We report a new method for ultrasensitive detection of Cu²⁺, which is based on changes in the tunnelling recognition current across self-assembled core–satellite gold nanoparticles (GNPs) networks functionalised with amino acids (L-cysteine). The addition of copper ions induces the formation of GNP/L-cysteine/Cu²⁺/L-cysteine/GNP molecular junctions and generates a significant decrease in the resistance through the networks. The networks are ultrasensitive to over ten orders range of copper ion concentrations.