Acerate ZnO whiskers and sodium alginate films: preparation and application in bioelectrochemistry of hemoglobin

Abstract

A novel biocompatible acerate ZnO whiskers (AZW) has been prepared. We explored AZW and sodium alginate for the construction of electrochemical biosensors. The composition, morphology, and size were studied by scanning electron microscopy. UV–vis spectra revealed that hemoglobin (Hb) adsorbed in the acerate ZnO whiskers and sodium alginate retained its native structure. The amperometric response was measured as a function of H₂O₂ concentration at a fixed potential of −0.25 V in phosphate-buffered saline (pH 7.0). The electrochemical parameters of Hb in acerate ZnO whiskers and sodium alginate were calculated with the results of the electron transfer coefficient (α) and the apparent heterogeneous electron transfer rate constant (k _s) as 0.5 and 2.5 s⁻¹, respectively, indicating good facilitation of the electron transfer between Hb and the modified electrode, which may result from the unique nanostructures and larger surface area of acerate ZnO whiskers. The hydrogen peroxide biosensor showed a fast response of <5 s of linear range 2.1 μM–4.8 mM, with a detection of 0.7 μM (S/N = 3). The apparent Michaelis–Menten constant $K_m^{{app}}$ is 0.8 mM. The biosensor possesses high sensitivity, good reproducibility, and long-term stability.