Carbon nanofiber modified with osmium based redox polymer for glucose sensing

Abstract

Electrochemical detection of glucose was performed on carbon nanofibers containing an osmium based redox polymer and using glucose oxidase enzyme. Redox polymer assembled on the nanofibers provided a more stable support that preserved enzyme activity and promoted the electrical communication to the glassy carbon electrode. The morphologies, structures, and electrochemical behavior of the redox polymer modified nanofibers were characterized by scanning electron microscope, energy dispersive spectrometer and voltammetry. The glucose oxidase showed excellent communication with redox polymer as observed with the increased activity toward glucose. Both cyclic voltammetry and amperometry showed a linear response with glucose concentration.  The linear range for glucose determination was from 1 to 12 mM with a relatively high sensitivity of 0.20±0.01 μA mM⁻¹ for glucose oxidase in carbon nanofibers and 0.10±0.01 μA mM⁻¹ without carbon nanofibers. The apparent Michaelis–Menten constant (K_m) for glucose oxidase with carbon nanofibers was 0.99 mM. On the other hand, the K_m value for the glucose oxidase without the nanofibers was 4.90 mM.