▎ 摘　　要

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 mu M to 19.8 mu M and from 19.8 mu M to 48.6 mu M, respectively. The detection limit is 0.37 mu M at 3 sigma. The developed biosensor exhibited excellent catalytic activity toward H2O2 over a wide linear range of 0.083-13.94 mu M with a detection limit of 0.08 mu M at 3 sigma. The facile and easy electrochemical approach used in this paper may open up a promising platform for protein immobilization and biosensor preparation. (C) 2013 Elsevier B.V. All rights reserved.