In this work, a label-free electrochemical immunosensor was constructed on the base of poly p-phenylenediamine (PPD) and GR nanocomposite (PPD-GR). Screen-printed electrodes modified with PPD-GR nanocomposite and applied to advance enzyme-free and label free electrochemical immunosensor for detection of protein biomarker neuron-specific enolase (NSE). It was found that the PPD-GR nanocomposite exhibits excellent electrocatalytic activity towards ascorbic acid (AA) oxidation as analytical signal based on EC' mechanism. Due to the excellent electrocatalytic activity of PPD-GR nanocomposite, determination of NSE antigen was based on its obstruction to the electrocatalytic oxidation of AA after binding to the surface of electrode through interaction with the anti-NSE. The proposed immunosensor exhibited a wide linear range of 1.0-1000 ng mL-1, with a low detection limit of 0.3 ng mL-1. Furthermore, the proposed immunosensor were successfully used for the determination of NSE antigen in human serum samples.
Keywords: Electrochemical immunosensor; Label-free; NSE; Neuron-specific enolase; Screen-printed electrode.
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