A look into the interaction of metal oxide thin films with biological media: Albumin and Fibrinogen adsorption
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A look into the interaction of metal oxide thin films with biological media: Albumin and Fibrinogen adsorption P. Silva-Bermudez1,2, S. Muhl1, M. Rivera3, S. E. Rodil1 1 Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n C.U., 04510, México. 2 Division de Estudios de Posgrado, Facultad de Odontología, UNAM, C.U., 04510, México. 3 Instituto de Física, UNAM, Circuito de la Investigación, C.U., 04510, México.
ABSTRACT In the present work, the adsorption of albumin and fibrinogen on Ta, Nb, Ti and Zr oxidesthin films deposited on Si (100) wafers by magnetron sputtering was studied in order to get a better understanding of the correlation among the surface properties of these oxides and the protein adsorption phenomena on their surfaces. The surface energy, hydrophobicity, chemical composition, roughness and atomic order of the films were characterized. The films were immersedfor 45 minutes in single protein solutions; either albumin or fibrinogenand the adsorbed protein layer on the films was studied ex-situ in a dry ambient using bothX-ray photoelectron spectroscopy and atomic force microscopy. The adsorption of albumin and fibrinogen on the films modified the surface morphology and decreased the surface roughness for all the four different metal oxides. The XPS results confirmed the presence of the protein on the surface of the films and showed that the two proteins studied were adsorbed without undergoing a major chemical decomposition. A correlation between the surface roughness,the polar component of the surface energy of the films and the atomic percentage of nitrogen on the films after protein adsorption, an indirect signal of the amount of protein adsorbed, was found for albumin and fibrinogen adsorption on Ta, Nb and Ti oxides; the largest the roughness or the polar component the largest amount of adsorbed protein. INTRODUCTION It is well known that whenever a foreign material comes in close contact with blood or physiological fluids, the surface of the material is almost immediately covered by a layer of adsorbed proteins. The nature, conformation and profile of the adsorbed proteins within the layer, guidethe next biological processes, greatly influencingthe fate of the material into the biological ambiance. The manner in which protein adsorption takes place on foreign materials is mainly driven by the surface physicochemical properties of the material. It is then of great importance for the development of biomaterials, to understand the interaction between foreign materials and the biological ambiance. The Ta, Nb, Zr and Ti oxides posses good corrosion and mechanical properties and have been widely reported as biocompatible materials, constituting a promising group of materials to develop biocompatible surfaces for orthopaedic and dental implants. In this work, we present
results from a systematic study of protein adsorption on these oxidessurfaces in an attempt to acquire a fundamental body of knowledge about the correlations that may exist between their surface physicochemical prope
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