%0 Journal Article
%T Direct Electron Transfer of Hemoglobin on Manganese III Oxide-Ag Nanofibers Modified Glassy Carbon Electrode
%A Masoud Negahdary
%A Gholamreza Mazaheri
%A Somyyeh Rad
%A Mohammadreza Hadi
%A Roya Malekzadeh
%A Mohammad Mahdi Saadatmand
%A Saeed Rezaei-Zarchi
%A Fariba Pishbin
%A Mojdeh Khosravian-hemami
%J International Journal of Analytical Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/375831
%X We investigated the electrochemical behavior of hemoglobin by glassy carbon electrode modified with Mn2O3-Ag nanofibers. The Mn2O3-Ag nanofibers were used as facilitator electron transfer between Hb and glassy-carbon-modified electrode. The Mn2O3-Ag nanofibers are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hemoglobin showed a quasireversible electrochemical redox behavior with a formal potential of £¿49£¿mV (versus Ag/AgCl) in 0.1£¿M potassium phosphate buffer solution at pH 7.0. The designed biosensor possesses good stability and reproducibility and achieves 95% of the steady-state current in less than five seconds. 1. Introduction Hemoglobin is a remarkable molecular machine that uses motion and small structural changes to regulate its action. Oxygen binding at the four heme sites in hemoglobin does not happen simultaneously. Once the first heme binds oxygen, it introduces small changes in the structure of the corresponding protein chain. The main function of red blood cell is transfer of O2 from lungs to tissue and transfer of CO2 from tissue to lungs. To accomplish these functions, red cells have hemoglobin (Hb). The Hb has iron in center of its structure [1]. The iron has important role in Hb structure [2]. We too used Hb in this project. Glassy carbon derives its name from exhibiting fracture behavior similar to glass, from having a disordered structure over large dimensions (although it contains a graphitic microcrystalline structure), and because it is a hard shiny material, capable of high polish [3¨C5]. Glassy carbon is particularly useful in electrochemical applications because of its low electrical resistivity, impermeability to gases, high chemical resistance, and because it has the widest potential range observed for carbon electrode. Glassy carbon was first prepared by Yamada and Sato in 1962 by the hight emperature pyrolysis of phenolic resin, and later by Davison who used cellulose as the starting material [6, 7]. They concluded that glassy carbon consists of long microfibrils that twist, bend, and interlock to form interfibrillar bonds, and that these microfibrils are randomly oriented [8]. Because of the desire to impart selectivity to electrochemical reactions and to control electron transfer kinetics, several investigators have utilized adsorption or covalent bonding of catalysts to the glassy carbon surface. The intent of these modifications is to control the interaction of molecules and ions with the electrode surface [9]. Small fibers in the submicron range, in comparison with larger
%U http://www.hindawi.com/journals/ijac/2012/375831/