High-performance Bi2WO6 nanoparticles for an integrated chip electrochemical dopamine sensor

Abnormal dopamine (DA) levels are implicated in numerous physiological disorders—including Parkinson's and Alzheimer's diseases—necessitating highly sensitive and selective analytical methods. Here we report a bismuth tungstate nanoparticle-modified glassy‑carbon electrode (Bi 2 WO 6 NPs/GCE) that enables chronoamperometric DA sensing with excellent electrocatalytic activity. Operating at an oxidation potential of +0.46 V, the sensor responds linearly to DA from 5 nM to 345 μM (R 2  = 0.9997) and offers a detection limit of 2.7 nM. To further miniaturise the platform, Bi 2 WO 6 NPs were drip-coated onto a laser-induced graphene pattern on eco-friendly polyvinyl chloride laser-induced graphene (PVC-LIG), producing a Bi 2 WO 6 NPs/Chip that functions inside a home-built integrated device. The chip requires only 70 μL electrolyte, operates at a lower potential (+0.22 V), and detects DA from 0.5 to 100 μM with a 14 nM detection limit. Both configurations exhibit excellent reproducibility (RSD < 1 %) and have been successfully applied to spike-and-recovery assays in human serum, demonstrating their promise for point-of-care DA monitoring.