title: Direct electron transfer and enhanced electrocatalytic activity of hemoglobin at iron-rich clay modified electrodes.
abstract: The possible role of structural iron in clays to promote direct electron transfer of hemoglobin (Hb) was investigated. Clays containing different amounts of iron situated in octahedral or tetrahedral sites have been used to modify glassy carbon electrodes: nontronite, synthetic montmorillonite, and saponite. A synthetic montmorillonite containing non-iron impurities was used as a reference. Interactions between Hb and these clays were studied with the establishment of adsorption isotherms and by the analysis of X-ray diffraction patterns, FTIR, and UV-vis spectra of the Hb-clay samples. The electrochemical behavior of clay modified electrodes (CME) was characterized by cyclic voltammetry in the presence of Hb in solution or adsorbed within the clays. Nontronite, which contains the highest amount of structural iron, enhanced significantly direct electron transfer of Hb. Finally, the electrocatalytic behavior of Hb-Nontronite CME in the presence of hydrogen peroxide was also studied, and the H(2)O(2) calibration curve was recorded under amperometric conditions for different bioelectrode configurations.
authors.affiliation: Departement de Chimie Moleculaire (DCM, UMR CNRS-UJF 5250) Universite Joseph Fourier, 38041 Grenoble, France.
authors.forename: Khaled
authors.initials: K
authors.lastname: Charradi
authors.forename: Claude
authors.initials: C
authors.lastname: Forano
authors.forename: Vanessa
authors.initials: V
authors.lastname: Prevot
authors.forename: Abdesslem
authors.initials: A
authors.lastname: Ben Haj Amara
authors.forename: Christine
authors.initials: C
authors.lastname: Mousty
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D000818:Animals; D001546:Bentonite / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D002417:Cattle; D000077215:Clay; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D004579:Electron Transport; D004583:Electrons; D006454:Hemoglobins / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D006454:Hemoglobins; D001546:Bentonite; C099453:saponite; D002244:Carbon; D007501:Iron; D000077215:Clay