Electrochemcial Detection of Acetylcholine using Enzyme Functionalized Nanoparticles

Abstract

Acetylcholine is a highly important non-electroactive neurotransmitter in the mammalian central nervous system. Its function is linked to memory and sleep, and it regulates, in part, mood and action via its connection to dopamine. A fast, sensitive method to detect the release of acetylcholine at the surface of a single cell is needed to gather data about the kinetics of exocytosis events in these systems.To this end, carbon fiber electrodes have been modified with electrodeposited gold nanoparticles to increase the effective electrode surface area and provide a high curvature surface for enzyme attachment. Acetylcholinesterase and choline oxidase were then deposited onto the gold surfaces to catalyze acetylcholine to hydrogen peroxide for electrochemical detection. The functionalized electrodes have been characterized to determine the KM and Vmax of the enzymes as well as the total enzyme coverage and gold nanoparticle surface area in order to optimize retained enzyme activity. This optimized design has proven capable of detecting release events from an artificial exocytotic system on a sub-second time scale.