Nanoparticulate Co-doped CuO/Multiwalled Carbon Nanotubes Composite for Dopamine

Dopamine is a key neurotransmitter crucial for learning, memory, emotion, sleep, and motor control. Its imbalance is linked to disorders such as Parkinson's disease and depression. To address the limitations of costly and specialized dopamine detection methods, this study developed an electrochemical sensor using copper oxide (CuO) and 3 mol% cobalt doped CuO (Co-doped CuO) composite with multiwalled carbon nanotubes (MWCNT). Both materials were synthesized via solution combustion, yielding single-phase nanoparticles under 100 nm. Cyclic voltammetry (CV) showed dopamine oxidation at 0.75 V for concentrations ranging from 0.1 to 100 μM. The Co-doped CuO/MWCNT composite exhibited enhanced electrocatalytic activity compared to undoped CuO/MWCNT, confirmed by CV and chronoamperometry. The Co-doped sensor demonstrated high sensitivity (65.001 μA⋅μM^-1⋅cm^-2), significantly higher than the 57.297 μA⋅μM^-1⋅cm^-2 observed for the undoped CuO-based electrode. A low detection limit is 0.0285 μM, and strong selectivity against interfering neurotransmitters like acetylcholine and serotonin. This innovative electrochemical method advances our understanding of CuO/MWCNT composites and offers a practical and effective solution for dopamine detection.