Ruihuan Zhao,Dongxiao Li,Nan Yin,Zhimin Guo,Dengchao Wang,Xin Yao
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.
Highly sensitive and specific detection and monitoring of trace norepinephrine (NE) in biological fluids and neuronal cell lines is essential for the investigation of pathogenesis of certain neurological diseases. Herein, we constructed a novel electrochemical sensor for real-time monitoring of NE released by PC12 cells based on glassy carbon electrode (GCE) modified with honeycomb-like nickel oxide (NiO)-reduced graphene oxide (RGO) nanocomposite. The synthesized NiO, RGO and the NiO-RGO nanocomposite were characterized using X-ray diffraction spectrogram (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The porous three-dimensional honeycomb-like structure of NiO and high charge transfer kinetics of RGO endowed the nanocomposite with excellent electrocatalytic activity , large surface area and good conductivity. The developed sensor exhibited superior sensitivity and specificity towards NE in a wide linear range from 20 nM to 14 μM and 14 μM–80 μM, with a low detection limit of 5 nM. The performances of the sensor in terms of excellent biocompatibility and high sensitivity allow it to be successfully employed in the tracking of NE release from PC12 cells under the stimulation of K + , providing an effective strategy for the real-time monitoring of cellular NE.
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