Study on a hydrogen peroxide biosensor based on horseradish peroxidase/GNPs-thionine/chitosan

A novel hydrogen peroxide biosensor based on horseradish peroxidase/GNPs-thionine/chitosan has been developed. Gold nanoparticles fixed with horseradish peroxidase were adsorbed on glassy carbon electrode by the chitosan which cross-linked with the electron mediator of horseradish peroxidase as the bridge linking agent. The assembly procedures were monitored by UV–visible spectral scanning, bio-layer interferometry, cyclic voltammetric and alternating current impedance. The chronoamperometry was used to measure hydrogen peroxide. The hydrogen peroxide biosensor linear range of detection is 1 × 10−7–1 × 10−4 mol/L, detection limit up to 5.0 × 10−8 mol/L. Moreover the stability, reproducibility and selectivity of the biosensor were also studied and the results confirmed that the biosensor exhibit fast response to hydrogen peroxide and possess high sensitivity, good reproducibility and long-term stability.

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► Glutaraldehyde was used as the bridge linking agent to covalently bonded thionine in chitosan, which is more stable and could effectively prevalent leakage of the electronic mediator.
► The effect of GNPs adsorbed HRP was first accurately characterized by bio-layer interferometry using the ForteBio Octer system.
► The application of self-assembly technology increases the biosensor stability.