Self-cleaning, reliable and accurate: new nanostructured device takes electroanalysis of neurotransmitters to the next level

A composite electrode with a sandwich structure combining the properties of silver nanoparticles and a titania (anatase polymorph) photoactive layer was prepared and electrochemically characterized by cyclic voltammetry and electrochemical impedance spectroscopy. A pronounced electrocatalytic effect was observed along with a great increase in the current intensity of the silver oxidation peak. Results are compared with literature data on bare silver nanoparticles. This peculiar electrode structure can be conveniently used for sensor applications. In fact, the device was successfully used for the determination of neurotransmitters such as dopamine, norepinephrine and serotonin in simulated biological matrices (liquor, serum and urine). Our optimized analytical methodology is not only characterized by high sensitivity and low detection limits (around 0.03 µM) but also by high selectivity in the presence of high concentrations of conventional interferents (uric and ascorbic acids). Moreover, the device shows under UV light self-cleaning properties of its titania overlayer, with complete removal of fouling, originated by the chemisorption of analytes and byproducts. Irradiating the device with UVA light, the initial sensor sensitivity was restored, making it reusable and suggesting its employment in integrated monitoring systems.