Imparting chemical specificity to nanometer-spaced electrodes

In this paper we are demonstrating an electrochemically driven self-assembling approach to achieve the space-resolved chemical functionalization of nanoelectrodes. After forming a self-assembled monolayer of electroactive quinones on a pair of nano-spaced (<100 nm) electrodes, we enabled the binding of ssDNA exclusively on a single nanoelectrode by controlling the oxidation state at each modified electrode. This procedure attained the chemical differentiation of otherwise identical nanoelectrodes as the immobilized ssDNA retained its hybridization ability. Furthermore, we established that Kelvin probe force microscopy is a suitable space-resolved analytical technique for detecting this chemical functionalization at the nanoscale. The reported approach, enabling the space-selective patterning of (bio)molecules on nanoelectrode surfaces, can find application in complex nanosensor structure and molecular electronics implementations.