Albumin adsorption on oxide thin films studied by spectroscopic ellipsometry

• Published in: Applied surface science 2011-12, Vol.258 (5), p.1711-1718
• Main Authors: Silva-Bermudez, P., Rodil, S.E., Muhl, S.
• Format: Article
• Language: English
• Subjects: Adsorption; Albumin; Ellipsometry; Metal oxide thin film; Protein adsorption; Spectroscopic analysis; Spectroscopy; Surface chemistry; Surface energy; Thin films; Titanium dioxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.10.020

► Bovine Serum Albumin adsorption on metal oxide thin films: Ta, Nb, Zr and Ti oxides. ► Adsorption is highly dependent on the films wettability. ► Hydrophobicity notoriously increases Bovine Serum Albumin adsorption. ► On the hydrophilic character films, adsorption increases with surface roughness. ► Adsorption on the hydrophilic films increases with surface energy polar component. Thin films of tantalum, niobium, zirconium and titanium oxides were deposited by reactive magnetron sputtering and their wettability and surface energy, optical properties, roughness, chemical composition and microstructure were characterized using contact angle measurements, spectroscopic ellipsometry, profilometry, X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The purpose of the work was to correlate the surface properties of the films to the Bovine Serum Albumin (BSA) adsorption, as a first step into the development of an initial in vitro test of the films biocompatibility, based on standardized protein adsorption essays. The films were immersed into BSA solutions with different protein concentrations and protein adsorption was monitored in situ by dynamic ellipsometry; the adsorption-rate was dependent on the solution concentration and the immersion time. The overall BSA adsorption was studied in situ using spectroscopic ellipsometry and it was found to be influenced by the wettability of the films; larger BSA adsorption occurred on the more hydrophobic surface, the ZrO 2 film. On the Ta 2O 5, Nb 2O 5 and TiO 2 films, hydrophilic surfaces, the overall BSA adsorption increased with the surface roughness or the polar component of the surface energy.