An aptasensor for tetracycline using a glassy carbon modified with nanosheets of graphene oxide

The authors describe an aptasensor for tetracycline (TET) based on the use of a glassy carbon electrode (GCE) modified with graphene oxide nanosheets. The latter were placed on the GCE to allow for the chemical immobilization of the aptamer. The fabrication of this biosensor was followed by techniques such as cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry. The effects of aptamer concentration, aptamer immobilization time, and tetracycline reaction time were investigated. Under optimum conditions, the data of electrochemical impedance spectroscopy were used to establish a calibration plot that covers the 0.1 pM to 10 μM TET concentration range, with a 29 fM detection limit. The method was applied to the determination of TET in tablets. In our perception, the methods may form the basis for numerous other impedimetric biosensors if appropriate aptamers are made available. (author)