Direct electrochemistry of hemoglobin entrapped in cyanoethyl cellulose film and its electrocatalysis to nitric oxide.

A water-soluble cyanoethyl cellulose (CEC), homogeneously synthesized in NaOH/urea aqueous solution, was used as an immobilization matrix to entrap proteins and enzymes. Then hemoglobin (Hb) was used as a template to fabricate CEC-Hb biomimetic membranes in which the Hb showed direct electrochemistry on a glass carbon electrode (GCE). The characterizations of CEC-Hb film were demonstrated by ultraviolet-visible (UV-vis) spectra, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of Hb in CEC film have been investigated and a pair of well-defined and quasi-reversible cyclic voltammetric peaks for the protein heme Fe(III)/Fe(II) redox couples was observed at about -0.369 V (vs. SCE). The CEC-Hb film exhibited a good electrocatalytic activity for the reduction of nitric oxide (NO). The amperometric response of the biosensor varied linearly with the NO concentration ranging from 1.1x10(-6) to 1.3x10(-4) mol L(-1). Moreover, the studied biosensor exhibited high sensibility, good reproducibility, and long-term stability. Finally, this method has applied to monitoring the NO release from biologic samples.