One-step construction of reagentless biosensor based on chitosan-carbon nanotubes-nile blue-horseradish peroxidase biocomposite formed by electrodeposition

Abstract A simple and controllable electrodeposition approach was established for one-step construction of novel reagentless biosensors by in situ formation of chitosan-carbon nanotubes-nile blue-horseradish peroxidase (CS-CNTs-NB-HRP) biocomposite film on electrode surface. The mediator effect of NB, conducting performance of CNTs and the biocompatible microenvironment of CS were combined by such one-step non-manual process. NB could interact with CNTs and resulted in good dispersion of CNTs-NB nanocomposites in aqueous solution. Cyclic voltammetry measurements demonstrated that electrons were efficiently shuttled between HRP and the electrode mediated by NB. The developed reagentless biosensor exhibited a fast amperometric response for the determination of H 2 O 2 and 95% of the steady-state current was obtained within 2 s. The linear response of the reagentless biosensor for the determination of H 2 O 2 ranged from 1.0 × 10 −6 to 2.4 × 10 −4  mol l −1 with a detection limit of 1.2 × 10 −7  mol l −1 . The biosensor exhibited high reproducibility and long-time storage stability. The as-prepared biosensor also showed effective anti-interference capability. The ease of the one-step non-manual technique and the promising feature of the biocomposite could serve as a versatile platform for fabricating electrochemical biosensors.