title: Fibrillar superstructure formation of hemoglobin A and its conductive, photodynamic and photovoltaic effects.
abstract: The fabrication of biomaterials which serve as functional scaffolds exhibiting diversified effects has been valued. We report here a unique strategy to fibrillate hemoglobin A (HbA), which exhibits multiple photoelectrochemical properties, and a subsequent specific defibrillation procedure. A subtle structural rearrangement of the α/β-subunits within the quaternary structure of HbA is responsible for the HbA fibril formation in the presence of 0.5% CHCl₃. The narrow pH dependence of the suprastructure formation around pH 7.4 illustrates the highly sensitive nature of the structural alteration. The CHCl₃-induced fibrils become disintegrated by ascorbic acid, indicating that the oxidation-reduction process of the iron within the heme moiety could be involved in stabilization of the fibrillar structures. The electron-transferring property of the iron allows the fibrils to exhibit not only their conductive behavior but also a photodynamic effect generating hydroxyl radicals in the presence of H(2)O(2) with light illumination. A photovoltaic effect is also demonstrated with the HbA fibrils, which generate an electric current on the fibril-coated microelectrode upon irradiation at 405nm. Taken together, the multiple effects of HbA fibrils and the selective fibrillation/defibrillation procedures could qualify the fibrils to be employed for various future applications in biotechnology, including bio-machine interfaces.
authors.affiliation: School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-744, Republic of Korea.
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Sungsoo
authors.initials: S
authors.lastname: Kang
authors.forename: Sang-Gil
authors.initials: SG
authors.lastname: Lee
authors.forename: Joon-Hyung
authors.initials: JH
authors.lastname: Jin
authors.forename: Jong Wan
authors.initials: JW
authors.lastname: Park
authors.forename: Sang Myun
authors.initials: SM
authors.lastname: Park
authors.forename: Seunho
authors.initials: S
authors.lastname: Jung
authors.forename: Seung R
authors.initials: SR
authors.lastname: Paik
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002725:Chloroform / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004553:Electric Conductivity; D004566:Electrodes; D004591:Electrophoresis, Polyacrylamide Gel; D006441:Hemoglobin A / Q000737:chemistry* / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration / Q000187:drug effects / Q000528:radiation effects; D017665:Hydroxyl Radical / Q000737:chemistry; D008027:Light; D055668:Photochemical Processes / Q000187:drug effects / Q000528:radiation effects*; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D017971:Tin Compounds; D017665:Hydroxyl Radical; C109984:indium tin oxide; D002725:Chloroform; D006441:Hemoglobin A; D001205:Ascorbic Acid