The high sensitive and selective detection of dopamine based on its electropolymerization by electrochemical surface plasmon resonance

Dopamine (DA) plays vital role in diagnosis and treatment of neurodegenerative disease. It is of high clinical relevance for developing simple, sensitive and selective DA detection method. But the electrochemical detection of DA still faces the problem of insufficient sensitivity, and generally need the complex material synthesis process to realize the selective detection of DA. In this work, we established a simple electrochemical surface plasmon resonance sensor for DA detection based on its electropolymerization property. The main interfering molecules of uric acid and ascorbic acid cannot undergo electropolymerization, while DA can produce polydopamine precipitation on the surface of Au film. The formation of polydopamine precipitation could amplify the SPR signal, and ensures the high selectivity and sensitivity of DA detection. The linear range is 0.01–1000 nM and the detection limit is as low as 1.4 pM. At the same time, this sensor has high selectivity for DA detection even in the presence of 50000-fold higher concentration of ascorbic acid and uric acid. Finally, the sensor was successfully applied to determine DA content in urine samples and DA released from PC12 cells under the stimulation of K + , demonstrating great potential in clinical applications. Different from UA and AA, DA can be electropolymerized under the applied potential and form polydopamine precipitation, which causes a large change in the refractive index of the Au film surface, and produce a large SPR signal, thus achieving the high sensitive and selective detection of DA. • A very simple EC-SPR method was established for DA detection. • The electropolymerization property of DA was creatively used in its SPR detection. • The formation of polydopamine improves the detection limit of DA to 1.4 pM. • The method is highly selective for DA even with coexistence of 50,000-fold UA and AA. • The method can be used for DA detection in urine samples and PC12 cells.