The fabrication of a gold nanoelectrode-nanopore nanopipette for dopamine enrichment and multimode detection.

It is important to further improve the electrophysiology and electrochemistry techniques of neurotransmitter detection. Here, we report the development of multifunctional nanopipette-based integrated approaches for the detection of neurotransmitters. We successfully fabricated a nanopipette with two independent functional units at the apex, a nanopore and a gold nanoelectrode (GNE). The GNE shows good electrochemical response to dopamine (DA). Furthermore, both the nanopore and nanoelectrode can effectively enrich DA but not ascorbic acid by electrical means. The enriched DA is then detected and analysed with an obviously improved signal-to-noise ratio by electrochemical methods and surface-enhanced Raman spectroscopy (SERS). In addition, with the addition of silver nanoparticles during enrichment, up to 10 times increase of the Raman intensity of DA can be observed.