Comparison between the performances of amperometric immunosensors for cholera antitoxin based on three enzyme markers

We developed a novel copolymer modified amperometric immunosensor for the detection of cholera antitoxin (anti-CT), by the electropolymerization of pyrrole-biotin and pyrrole-lactitobionamide monomers on platinum or glassy carbon electrodes. In the detection of cholera antitoxin we have used three enzymatic marker detection systems based on HRP-labeled rabbit IgG antibodies, biotinylated polyphenol-oxidase (PPO-B) and biotinylated glucose-oxidase (GOX-B). The comparison of the electro-enzymatic performances of these three configurations with different substrates, clearly shows that the more sensitive amperometric immunosensor was based on HRP with a lower limit of detection of 50 ng/ml anti-CT using hydroquinone/H₂O₂ system. The response time for this substrate was in range of 5-30 s. The HRP-amperometric immunosensor has thus proven to be a very sensitive tool to monitor nanomolar concentrations of anti-CT.