Electrochemical biosensing platform based on carboxymethyl cellulose functionalized reduced graphene oxide and hemoglobin hybrid nanocomposite film

A novel, biocompatible sensing strategy based on carboxymethyl cellulose (CMC) functionalized reduced grapheme oxide (rGO) nanocomposite film for immobilizing the hemoglobin (Hb) was first developed. The rGO-CMC/Hb film was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectra (EIS). The direct electrochemistry of rGO-CMC/Hb modified electrodes were investigated by cyclic voltammetry. The results indicated that Hb retained its bioactivity on the modified electrode and showed a couple of well-defined and quasi-reversible redox peaks. The immobilized Hb exhibited excellent bioelectrocatalytic activity toward the reduction of NO and H2O2. Two linear segments with different slopes for NO concentration were from 0.864 μM to 19.8 μM and from 19.8 μM to 48.6 μM, respectively. The detection limit is 0.37 μM at 3σ. The developed biosensor exhibited excellent catalytic activity toward H2O2 over a wide linear range of 0.083–13.94 μM with a detection limit of 0.08 μM at 3σ. The facile and easy electrochemical approach used in this paper may open up a promising platform for protein immobilization and biosensor preparation.