Microfabricated FSCV-compatible microelectrode array for real-time monitoring of heterogeneous dopamine release.

Fast scan cyclic voltammetry (FSCV) has been used previously to detect neurotransmitter release and reuptake in vivo. An advantage that FSCV has over other electrochemical techniques is its ability to distinguish neurotransmitters of interest (i.e. monoamines) from their metabolites using their respective characteristic cyclic voltammograms. While much has been learned with this technique, it has generally only been used in a single working electrode arrangement. Additionally, traditional electrode fabrication techniques tend to be difficult and somewhat irreproducible. Described in this report is a fabrication method for a FSCV compatible microelectrode array (FSCV-MEA) that is capable of functioning in vivo. The microfabrication techniques employed here allow for better reproducibility than traditional fabrication methods of carbon fiber microelectrodes, and enable batch fabrication of electrode arrays. The reproducibility and electrochemical qualities of the probes were assessed along with crosstalk in vitro. Heterogeneous release of electrically evoked dopamine was observed in real-time in the striatum of an anesthetized rat using the FSCV-MEA. The heterogeneous effects of pharmacology on the striatum were also observed and shown to be consistent across multiple animals.