Characterization and electrochemical study of hemoglobin–carbon nanoparticles–polyvinyl alcohol nanoporous hybrid film

Abstract

A hybrid film is fabricated by casting hemoglobin (Hb)–carbon nanoparticles (CNPs)–polyvinyl alcohol (PVA) suspension on glassy carbon electrode (GCE). The resulting film shows a three-dimensional nanoporous structure. In the hybrid film, the ultraviolet visible (UV–Vis) absorption spectra of Hb keep almost unchanged. The organic–inorganic hybrid material can promote the direct electron transfer of Hb. A pair of well-defined and quasireversible peaks with a formal potential of −0.348 V (vs saturated calomel electrode) is obtained, which is caused by the electrochemical reaction of the Fe(III)/Fe(II) couple of Hb. The electron transfer rate constant (k s) is estimated to be 3.9 s−1. The immobilized Hb exhibits high stability and excellent electrochemical catalysis to the reduction of oxygen (O2), hydrogen peroxide (H2O2), and nitrite ( $$NO^{ - }_{2} $$ ). The catalytic currents are linear to the concentrations of H2O2 and $$NO^{ - }_{2} $$ from 1.96 to 112 μM and from 0.2 to 1.8 mM, respectively. Therefore, the hybrid film may be a good matrix for protein immobilization and biosensor fabrication.