Reversible redox activity of ferrocene functionalized hydroxypropyl cellulose and its application to detect H2O2

• Novel ferrocene functionalized hydroxypropyl cellulose (HPC-Fc) was synthesized by azide-alkyne cycloaddition.
• HPC-Fc exhibits an excellent reversible redox activity.
• HPC-Fc can be used as an attractive matrix for the immobilization of HRP for the hydrogen peroxide detection.
• The biosensor exhibits a good electroanalytic linear response toward H2O2 and a high sensitivity.

Novel ferrocene functionalized hydroxypropyl cellulose (HPC-Fc) were prepared by azide-alkyne cycloaddition and characterized. HPC-Fc exhibits an excellent reversible redox activity and could establish amazing electron transfer ability between enzyme and electrode. HPC-Fc and horseradish peroxidase (HRP) were coated on a platinized carbon electrode to prepare an amperometric biosensor for hydrogen peroxide (H2O2) detection. The amperometric response was measured as a function of H2O2 concentration at a fixed potential of 0.35 V in 100 mM phosphate buffer solution (pH 7.0). The novel biosensor exhibits a fast linear response toward H2O2 in the range of 0.1–8 μM with sensitivity of 4.21 nA/μM. Moreover, the enzyme assays measured by the spectrophotometer method confirm that abundant hydroxyl groups of HPC backbones are conductive for HRP to maintaining or even enhancing their activity. The redox active HPC-Fc with the unique properties of both ferrocene and cellulose is a good candidate for biosensor applications.