Electrodeposited biotinylated polypyrrole as an immobilization method for impedimetric immunosensors

The potentialities of an electrodeposited biotinylated polypyrrole film as an immobilization matrix for the fabrication of impedimetric immunosensors are described. Biotinylated antibody (anti-human IgG), used as a model system, was attached to free biotin groups on the electrogenerated polypyrrole film using avidin as a coupling reagent. The resulting recognition interface consisted of a highly oriented monolayer immobilized onto the polymer surface. Cyclic voltammetry was used to characterize the polymer film. Additionally, scanning electron microscopy and atomic force microscopy were used to investigate the morphology of the immobilized material. This immobilization method allows the obtention of a highly reproducible and stable device. The resulting immunosensor has a linear dynamic range of 10-80 ng.ml^-1 of antigen and a detection limit of 10 pg.ml^-1. Furthermore, this immunosensor exhibited minor loss in response after two regeneration steps.