Electrochemical Immunosensor Based on the Interactions Between Polypyrrole and Cobalt (II) Salicylaldiimine Dendrimer

Abstract

Transglutaminase is primarily involved with activation and progression of coeliac disease through the ingestion of gluten which initiates the production of antibodies against transglutaminase. This results in the damage of the small intestine reducing the diffusion of digested foods into the blood vessels. The diagnosis of coeliac disease can be done by the measurement of antibodies against transglutaminase. This work involves the development of an electrochemical immunosensor for the detection of anti-transglutaminase antibodies. A platinum modified polypyrrole-cobalt (II) salicyladiimine metallodendrimer composite capped with transglutaminase and bovine serum albumin was used for the determination of anti-transglutaminase antibodies. Surface roughness of 879.24 nm, 76.55 nm and 364.27 nm for polypyrrole, cobalt (II) salicyladiimine metallodendrimer and their respective composite in conjunction with cyclic voltammetry showed that such composites provide a suitable micro-environment for monitoring antibody-antigen interactions. Electrochemical impedance spectroscopy parameters such as exchange current and heterogeneous rate constant are used to evaluate immunosensor where the rate constants were 2.7 x 10-6 cm2 s-1, 4.6 x 10-6 cm2 s-1 and 4.16 x 10-6 cm2 s-1 for cobalt (II) salicyladiimine metallodendrimer, polypyrrole and their composite. Impedimetric immunosensor gave a limit of detection of 201 ng mL-1 and linear range of 10-5-10-4 mg mL-1 with correlation coefficient of 0.948.