Nanoimprinted arrays of glassy carbon nanoelectrodes for improved electrochemistry of enzymatic redox-mediators

In the present study, the preparation and electrochemical application of perfectly ordered arrays of glassy carbon nanoelectrodes (GC-NEAs) is presented. After careful morphological characterization, we examined the voltammetric behaviour on GC-NEAs of some redox mediators commonly used in enzymatic electrochemical biosensors. GC-NEAs were fabricated by using nanoimprint lithography to generate ordered arrays of nanoholes, with average radius of 145 nm, onto a polycarbonate thin film deposited on a glassy carbon plate. The redox mediators examined were (ferrocenylmethyl)trimethylammonium (FA+) as typical redox mediator for oxidase enzymes and Azure A and B as examples of mediators used for reductase enzymes. The voltammetric signals recorded indicate that the here prepared GC-NEAs operate under total overlap diffusion conditions, with an accessible potential window significantly wider than the one typical of arrays of gold nanoelectrodes. Interestingly, the electrochemical behaviour of the GC-NEAs perfectly fits with what expected on the basis of the geometrical features of the array demonstrating the role of these parameters in ruling the contribution of capacitive and faradic currents of the array which reflect in improved detection capabilities.