Miniaturized Enzymatic Biosensor via Biofunctionalization of the Insulator of Nanoelectrode Ensembles

An innovative second generation enzymatic microbiosensor was developed exploiting the properties of nanoelectrode ensembles (NEEs) prepared by electroless gold deposition in track-etched polycarbonate (PC) membrane. As a case study, a miniaturized glucose biosensor was developed and characterized. The micro-NEE glucose biosensor was obtained by immobilizing glucose oxidase (GOx) on the nonconductive PC component of the NEE, while the Au nanoelectrodes were used exclusively as transducers. (Ferrocenylmethyl)trimethylammonium cation (FA+) was used as the redox mediator. The immobilization of GOx on the PC didn’t affect the electrochemical performances of the NEE nor the catalytic activity of the enzyme. The proposed biosensor showed outstanding analytical performances with a detection limit of 36µM. The nanostructured biosensor was miniaturized down to a micro-NEE with overall radius of 400 µm, without any degradation of the analytical performances.