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 1.1 × 10−6 to 1.3 × 10−4 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.