The self-assembly, characterization and application of hemoglobin immobilized on Fe3O4@Pt core-shell nanoparticles

Direct electron transfer is demonstrated to occur between an electrode and hemoglobin that was immobilized on a film of Fe3O4@Pt-chitosan (Fe3O4@Pt-CS). Magnetic nanoparticles composed of Fe3O4 were prepared by a chemical coprecipitation method, and platinum nanoparticles were deposited on the Fe3O4 surface to form novel core-shell nanocomposites. In phosphate buffer solution of pH 7.0, the hemoglobin-Fe3O4@Pt-CS assembly on a modified glassy carbon electrode exhibited a couple of well-defined and quasi-reversible redox peaks. The formal potential E0′ was about −0.35 V. The electrode displayed excellent electrocatalytic activity towards oxygen and hydrogen peroxide reduction without the need for an electron mediator.