Peroxidase-modified cup-stacked carbon nanofiber networks for electrochemical biosensing with adjustable dynamic range

Abstract

Cup-stacked carbon nanofibers (CSCNFs) were treated with ozone to introduce oxygen-containing groups to the edges of the graphene cups. The O/C atomic ratio at the surface was estimated to be 5.3 × 10⁻². The hydrophilic CSCNFs were used for constructing a three-dimensional network that works both as an electrical nanowire and an enzyme support. Horseradish peroxidase (HRP) molecules were immobilized onto the network for amperometric sensing of H₂O₂ and inhibition-based sensing of cyanide. Both the upper sensing limit of H₂O₂ and the upper and lower sensing limits of cyanide were controlled by about two orders of magnitude by changing the HRP coverage.