Protein adsorption on nano-scaled, rippled TiO2 and Si surfaces

Abstract

We synthesized nano-scaled periodic ripple patterns on silicon and titanium dioxide (TiO2) surfaces by xenon ion irradiation, and performed adsorption experiments with human plasma fibrinogen (HPF) on such surfaces as a function of the ripple wavelength. Atomic force microscopy showed the adsorption of HPF in mostly globular conformation on crystalline and amorphous flat Si surfaces as well as on nano-structured Si with long ripple wavelengths. For short ripple wavelengths the proteins seem to adsorb in a stretched formation and align across or along the ripples. In contrast to that, the proteins adsorb in a globular assembly on flat and long-wavelength rippled TiO2, but no adsorbed proteins could be observed on TiO2 with short ripple wavelengths due to a decrease of the adsorption energy caused by surface curvature. Consequently, the adsorption behavior of HPF can be tuned on biomedically interesting materials by introducing a nanosized morphology while not modifying the stoichiometry/ chemistry. © The Author(s) 2012.