title: Electrochemistry and electrocatalytic properties of hemoglobin in layer-by-layer films of SiO2 with vapor-surface sol-gel deposition.
abstract: In this paper, layer-by-layer {Hb/SiO2}n films assembled by alternate adsorption of positively charged hemoglobin (Hb) and vapor-surface sol-gel deposition of silica at 50 degrees C onto a glassy carbon electrode were reported. The result films were characterized with cyclic voltametery, electrochemical impedance spectroscopy, UV-vis spectroscopy, and SEM, and the direct electrochemical and electrocatalytic properties of Hb in these layer-by-layer films were investigated. A pair of well-defined quasi-reversible cyclic voltammetric peaks were observed, and the formal potential of the heme FeIII/FeII redox couple was found to be -0.330 V(vs SCE). The electron-transfer behavior of Hb in {Hb/SiO2}n films was dependent on the vapor temperature, the number of layers, and the pH of the Hb solution, based on which a set of optimized conditions for film fabrication was inferred. The hemoglobin in{Hb/SiO2}n films displayed good electrocatalytic activity to the reduction of hydrogen peroxide, and H2O2 had linear current response from 1.0 x 10(-6) to 2.0 x 10(-4) M with a detection limit of 5.0 x 10(-7) M (S/N = 3). The apparent heterogeneous electron-transfer rate constant (ks) was 1.02 +/- 0.03 s(-1), and the apparent Michaeli-Menten constant (Kmapp) was 0.155 mM, indicating a potential application in the third-generation biosensor.
authors: Department of Chemistry, East China Normal University, 3663 Zhongshan Road(N), Shanghai, 200062, People's Republic of China.
authors: Guoyue
authors: G
authors: Shi
authors: Zhiyu
authors: Z
authors: Sun
authors: Meichuan
authors: M
authors: Liu
authors: Li
authors: L
authors: Zhang
authors: Ye
authors: Y
authors: Liu
authors: Yunhe
authors: Y
authors: Qu
authors: Litong
authors: L
authors: Jin
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D005782:Gels; D006454:Hemoglobins / Q000737:chemistry*; D006861:Hydrogen Peroxide; D008854:Microscopy, Electron; D010084:Oxidation-Reduction; D019904:Polymethyl Methacrylate; D012822:Silicon Dioxide; D013057:Spectrum Analysis; D014835:Volatilization
chemical_list: D005782:Gels; D006454:Hemoglobins; D012822:Silicon Dioxide; D019904:Polymethyl Methacrylate; D006861:Hydrogen Peroxide