A Novel Electrochemical Immunosensor for Detection of AngiotensinII at a Glass Carbon Electrode Modified by Carbon Nanotubes/Chitosan Film

A novel electrochemical competitive immunosensor was successfully developed for the detection AngiotensinII using the glass carbon electrode (GCE) modified with the single-walled carbon nanotubes/chitosan (SWNTs/CS) film. The electrochemical sensor was firstly prepared by covalently immobilizing AngII on SWNTs/CS modified GCE. Then the modified GCE was incubated with the mixture solution of Bio-Anti-AngII antibody and target AngII. After the competitive immunoreactions, the ST-AP was captured on the immunosensor surface to catalyze the hydrolysis of the substrate alpha-NP in the DEA solution. The whole fabrication processes of the immunosensor were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, the immunosensor showed a specific response to a small molecular target AngII and the DPV signals linearly decreased in the range of 0.05 to 10 mu g mL(-1) AngII with a detection limit of 0.03 mu g mL(-1). Good specificity and reproducibility were obtained for this immunosensor and it was applied to assay the AngII in spiked serum. This facile electrochemical immunosensor strategy was firstly used to detect AngII and might be a promising method for detection of AngII for clinical diagnostic application in the future.