Fabrication of a Flexible Lab-Made PVP-CuO Modified Electrochemical Sensor for Dual Detection of Dopamine and Paracetamol

Flexible screen-printed electrodes (FSPEs) fabricated from eco-friendly and recyclable materials represent a promising strategy for developing cost-effective and sustainable electrochemical sensors. In this study, FSPEs were fabricated on polyethylene terephthalate (PET) substrates obtained from recycled plastic bottles, using carbon and silver conductive inks, with colorless nail polish as an insulating layer. To enhance electrochemical performance, the working electrode surface was modified with a polyvinylpyrrolidone-copper oxide (PVP-CuO) nanocomposite via drop casting. The PVP matrix ensured uniform film formation and improved electrode stability, while CuO nanoparticles provided abundant electroactive sites and promoted faster electron transfer. The fabricated electrode displayed notable electrocatalytic activity for the simultaneous determination of dopamine (DA) and paracetamol (PAR), two analytes commonly present in biological fluids and pharmaceutical formulations. In addition, the PVP/CuO modification significantly improved the electrode’s sensitivity and selectivity toward both analytes by facilitating efficient analyte–electrode interactions and enhancing charge-transfer kinetics. Under optimized conditions, the PVP/CuO modified FSPE sensor demonstrated low detection limits of 1.188 μM for DA and 1.024 μM for PAR, with a wide linear range of 4.0–1000.0 μM and good reproducibility. The proposed platform offers a sustainable, low-cost, and efficient approach for the simultaneous electrochemical detection of DA and PAR.