title: Immobilization of hemoglobin on zirconium dioxide nanoparticles for preparation of a novel hydrogen peroxide biosensor.
abstract: Direct electrochemistry and thermal stability of hemoglobin (Hb) immobilized on a nanometer-sized zirconium dioxide (ZrO2) modified pyrolytic graphite (PG) electrode were studied. The immobilized Hb displayed a couple of stable and well-defined redox peaks with an electron transfer rate constant of (7.90 +/- 0.93)s(-1) and a formal potential of -0.361 V (-0.12 V versus NHE) in 0.1M pH 7.0 PBS. Both nanometer-sized ZrO2 and dimethyl sulfoxide (DMSO) could accelerate the electron transfer between Hb and the electrode. Spectroscopy analysis of the Hb/ZrO2/DMSO film showed that the immobilized Hb could retain its natural structure. This modified electrode showed a high thermal stability up to 74 degrees C and an electrocatalytic activity to the reduction of hydrogen peroxide (H2O2) without the aid of an electron mediator. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging from 1.5 to 30.2 microM with a detection limit of 0.14 microM at 3sigma. The apparent Michaelis-Menten constant KMapp for H2O2 sensor was estimated to be (0.31 +/- 0.02) mM, showing a high affinity.
authors.affiliation: Department of Chemistry, Institute of Analytical Science, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, PR China.
authors.forename: Songqin
authors.initials: S
authors.lastname: Liu
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Dai
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Chen
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D015374:Biosensing Techniques; D002384:Catalysis; D006454:Hemoglobins; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000032:analysis*; D036103:Nanotechnology; D013057:Spectrum Analysis; D015040:Zirconium
chemical_list: D006454:Hemoglobins; D006861:Hydrogen Peroxide; D015040:Zirconium; C028541:zirconium oxide