One-step construction of biosensor based on chitosan–ionic liquid–horseradish peroxidase biocomposite formed by electrodeposition

A simple and controllable electrodeposition approach was established for one-step construction of hydrogen peroxide (H2O2) biosensors by in situ formation of chitosan–ionic liquid–horseradish peroxidase (CS–IL–HRP) biocomposite film on electrode surface. A highly porous surface with orderly three-dimensional network was revealed by scanning electron microscopy (SEM) investigation. The biocomposite provided improved conductivity and biocompatible microenvironment. The developed biosensor exhibited a fast amperometric response for the determination of H2O2 and 95% of the steady-state current was obtained within 2 s. The linear response of the developed biosensor for the determination of H2O2 ranged from 6.0 × 10−7 to 1.6 × 10−4 M with a detection limit of 1.5 × 10−7 M. Performance of the biosensor was evaluated with respect to possible interferences and a good selectivity was revealed. The fabricated biosensor exhibited high reproducibility and long-time storage stability. The ease of the one-step non-manual technique and the promising feature of biocomposite could serve as a versatile platform for the fabrication of electrochemical biosensors.