Impedance immunosensor for bovine interleukin-4 using an electrode modified with reduced graphene oxide and chitosan.

We have developed an impedimetric immunosensor for the determination of bovine interleukin-4, a cytokine involved in the immune response to certain parasites and the development of some bovine diseases. Monoclonal antibody against bovine interleukin-4 was immobilized on a glassy carbon electrode modified with reduced graphene oxide and chitosan. Transmission electron microscopy, static contact angle measurement, and electrochemical impedimetry are used to characterize the immunosensor. The nanocomposite possesses a high surface area that is well suited for the immobilization of antibody. The relative increase in impedance on exposure of the sensor to solutions containing bovine interleukin-4 is linearly proportional to its logarithmic concentration in the 0.1 to 50 ng mL and the detection limit is 80 pg mL. The immunosensor is selective, well reproducible, and acceptably stable. It presents a useful tool for further studies on the role of this cytokine in the immunology and pathogenesis of bovine diseases. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]