• Muhl, S.
• Silva-Bermudez, P.

Abstract

One of the first events occurring upon foreign material-biological medium contact is the adsorption of proteins, which evolution greatly determines the cells response to the material. Protein-surface interactions are a complex phenomenon driven by the physicochemical properties of the surface, protein(s) and liquid medium involve in the interaction. In this article the adsorption of fibrinogen (Fbg) onto Ta<SUB>2</SUB>O<SUB>5</SUB>, Nb<SUB>2</SUB>O<SUB>5</SUB>, TiO<SUB>2</SUB> and ZrO<SUB>2</SUB> thin films is reported. The adsorption kinetics and characteristics of the adsorbed fibrinogen layer were studied in situ using dynamic and spectroscopic ellipsometry. The films wettability, surface energy (γ<SUP>LW/AB</SUP>) and roughness were characterized aiming to elucidate their correlations with Fbg adsorption. The adsorption rate changed accordingly to the film; the fastest adsorption rate and highest Fbg surface mass concentration (Γ) was observed on ZrO<SUB>2</SUB>. The hydrophobic/hydrophilic character of the oxide highly influenced Fbg adsorption. On Ta<SUB>2</SUB>O<SUB>5</SUB>, Nb<SUB>2</SUB>O<SUB>5</SUB> and TiO<SUB>2</SUB>, which were either hydrophilic or in the breaking-point between hydrophilicity and hydrophobicity, Γ was correlated to the polar component of γ<SUP>LW/AB</SUP> and roughness of the surface. On ZrO<SUB>2</SUB>, clearly hydrophobic, Γ increased significantly off the correlation observed for the other films. The results indicated different adsorption dynamics and orientations of the Fbg molecules dependent on the surface hydrophobic/hydrophilic character.

Topics

• impedance spectroscopy
• surface
• thin film
• ellipsometry
• surface energy