An ISFET-based immunosensor for the detection of β-Bungarotoxin

Abstract

An ion-sensitive field effect transistor (ISFET)-based immunosensor was developed to detect/quantitate β-Bungarotoxin (β-BuTx), a potent presynaptic neurotoxin from the venom of Bungarus multicinctus. A murine monoclonal antibody (mAb 15) specific to β-BuTx was immobilized onto silicon nitride wafers after silanization and activation with glutaraldehyde. A chip based enzyme linked-immunosorbantassay (ELISA) was performed to ascertain antigen binding to the immobilized antibody. To develop an electrochemical immunosensing system for the detection/quantitation of β-BuTx, an ISFET was used as a solid phase detector. MAb 15 was immobilized on the gate region of the ISFET. The antigen antibody reaction was monitored by the addition of urease conjugated rabbit anti-β-BuTx antibodies. The sensor can detect toxin level as low as 15.6 ng/ml. The efficacy of the sensor for the determination of β-BuTx from B. multicinctus venom was demonstrated in mouse model. Toxin concentration was highest at the site of injection (748.0±26 ng/ml) and moderate amount was found in the plasma (158.5±13 ng/ml).