Abstract: A novel label-free electrochemical aptamer biosensor was developed by using cysteine blocker as the electrochemical redox probe, and was used for the determination of thrombin. Electrochemical impedance spectroscopy was used to monitor the self-assembly process of aptamer biosensor. The electrochemical behaviors of the biosensor were characterized by the cyclic voltammetry and differential pulse voltammetry. The effects of the incubation time and test pH were investigated on the response of aptamer biosensor. The biosensor shows a good linear range of 10.0～10000 μg/L for thrombin with a detection limit of 2.47 μg/L.

Key words: Cysteine, blocker, redox probe, Aptamer, biosensor