Sensitive enzymatic determination of neurotransmitters in artificial sweat

Dopamine (DA) and epinephrine (EN) are two phenolic molecules that are used in the human body and secreted in the brain actuating as neurotransmitters. As both molecules are highly important in the brain and the central nervous system, monitoring of their concentrations would enable better understanding of their importance and role in different physiological conditions. Copper efflux oxidase from Escherichia coli was shown in the past to have the ability of oxidizing polyphenolic compounds. As such, we have engineered this enzyme for its site-specific attachment to an electrode for the detection of DA and EN in high resolution and sensitivity. Here we present an enzymatic biosensor that enables the detection of such molecules with a 10 nM resolution and a linear range of up to 100 nM in artificial sweat samples. The presented biosensor could be used for the determination of catecholamines in different bodily fluids.