Polypyrrole–neutravidin layer for impedimetric biosensor

Polypyrrole synthesis and neutravidin entrapment inside the polymer were performed simultaneously in one step using a controlled anodic current passing. The incorporation of neutravidin within the electrogenerated film was confirmed by FTIR and impedance spectroscopy. Biotinylated anti-triazine Fab fragment was attached to the PPy/neutravidin modified electrode throughout the well-studied biotin–neutravidin interaction. During impedance measurements, the charge transfer resistance increased gradually with atrazine concentration whereas no significant response was recorded after rabbit IgG injection. The immunosensor was very sensitive to atrazine antigen in the range of 0.1–200 ng/ml and the detection limit attained 0.1 ng/ml.