Designing and fabrication of a novel sensitive electrochemical aptasensor based on poly (L-glutamic acid)/MWCNTs modified glassy carbon electrode for determination of tetracycline

Here in, a high sensitive electrochemical aptasensor for the determination of tetracycline has been developed using of MWCNTs and electropolymerized poly (L-glutamic acid) as a suitable platform for immobilization of anti-TET aptamer. Electropolymerization of biocompatible polymer was performed by cyclic voltammetry (CV) and constant potential-based techniques. Due to the unique properties of impedance technique (electrochemical impedance spectroscopy (EIS)) and modification of electrode surface by constant potential electro-polymerizarion, a wide linear range (1.0 x 10(-16)-1.0 x 10(-6) M) and low detection limit (3.7 x 10(-17)) for TET detection was observed. The stepwise modification process of the aptasensor fabrication was characterized by CV, EIS and scanning electron microscopy (SEM). The optimization of the loading amount of MWCNTs, detection time of TET, aptamer immobilization time, anti-TET aptamer concentration was performed in detail. Under the optimum conditions, the EIS and DPV data were used to establish a calibration curve. The developed aptasensor were successfully applied for determination of tetracycline in drug and honey samples.