Non-enzymatic dopamine oxidation-based sensing using CuTCNQ as a redox-active interface

Abstract The precise and selective detection of dopamine (DOP) is crucial for identifying neurological diseases, yet high costs and complexity limit traditional approaches. Here, we report a CuTCNQ-based electrochemical sensor that enables enhanced stability and conductivity, facilitating fast and reversible electron transfer between Cu 2 ⁺ and Cu⁺ redox states. The active redox couple enables DOP quantification using amperometry at + 0.20 V, showing a linear response from 0.10 to 0.55 µM with a limit of detection of 0.085 µM (S/N = 3). The sensor demonstrated excellent selectivity with negligible interference from glucose, ascorbic acid, and paracetamol, and maintained over 95% of its initial current after 60 days of storage. Density functional theory (DFT) calculations reveal robust Cu–O coordination with dopamine, explaining the rapid electron transfer kinetics. CuTCNQ-based sensors provide a cost-effective, stable, and scalable platform for DOP sensing, with potential future applications in real-time, wearable neurosensing.