An amperometric enzyme biosensor based on in situ electrosynthesized core–shell nanoparticles

This work describes a new approach to the construction of an amperometric biosensor for hydrogen peroxide detection based on in situ electrosynthesized gold/polyaniline core–shell nanocomposites on conducting ITO electrode. The immobilization of the enzyme, horseradish peroxidase (HRP), on the polyaniline nanofilm was carried out by electrostatic attachment approach. Results showed that the immobilized HRP exhibited enhanced performance toward the reduction of H₂O₂, in comparison with other bulk polyaniline (PANI)-based H₂O₂ biosensor and metallic nanoparticles incorporated PANI systems. The resulting biosensor shows a fast amperometric response (<2 s) to H₂O₂. A linear range from 0.2 to 80 μM for the detection of H₂O₂ was observed with a sensitivity of 20.5 μA/mM and a detection limit of 0.16 μM at a signal-to-noise ratio of 3. Moreover, the biosensor has a good reproducibility, and long-term stability.