Dopamine Fluorescent Sensor Based on Green Synthesized Copper Oxide Nanoparticles and Tyrosinase

Dopamine (DA) is a catecholamine that is an essential neurotransmitter in the human body. Slight variation in its concentration and metabolism leads to severe neurological damage or diseases, such as Parkinson’s, Alzheimer’s, schizophrenia, and many more. It could be addressed at some scale by early detection. In this study, copper oxide nanoparticles (NPs) were synthesized by green route (P-Cu
₂
O NPs) with
Artemisia absinthium
leaf extract, which acts as a reducing agent, accompanied by the enzyme tyrosinase (Tyr) used as a sensing material. Molecular docking is performed to predict the interaction between DA, Cu
₂
O NPs, and Tyr. The structural characterization of the NPs and interaction with DA via fluorescence spectroscopy was carried out to determine the sensitivity. The central composite design (CCD) was used to optimize the experimental conditions, such as the volume of NPs, enzyme, and temperature. The combination P-Cu
₂
O + Tyr (PT) showed a selective response to DA and did not show any response to interfering analytes, such as ascorbic acid (AA), cysteine, and tyrosine. The limit of detection (LOD) of DA is observed to be 5
$\mu \text{M}$
. This study indicates that PT can be a fluorescent probe in detecting DA.