1 research outputs found
Facets of Protein Assembly on Nanostructured Titanium Oxide Surfaces
One key for the successful integration of implants into the human body is the control of protein adsorption
by adjusting the surface properties at different length scales. This is particularly important for titanium
oxide, one of the most common biomedical interfaces. As for titania (TiO2) the interface is largely
defined by its crystal surface structure, it is crucial to understand how the surface crystallinity affects the
structure, properties and function of protein layers mediating subsequent biological reactions. For rutile
TiO2 we demonstrate that the conformation and relative amount of human plasma fibrinogen (HPF) and
the structure of adsorbed HPF layers depend on the crystal surface nanostructure by employing thermally
etched multi-faceted TiO2 surfaces. Thermal etching of polycrystalline TiO2 facilitates a nanoscale crystal
faceting and, thus, the creation of different surface nanostructures on a single specimen surface. Atomic
force microscopy shows that HPF arranges into networks and thin globular layers on flat and irregular
crystal grain surfaces, respectively. On a third, faceted category we observed an alternating conformation
of HPF on neighboring facets. The bulk grain orientation obtained from electron backscatter diffraction
and thermodynamic mechanisms of surface reconstruction during thermal etching suggest that the grain
and facet surface-specific arrangement and relative amount of adsorbed proteins depend on the associated
free crystal surface energy. The implications for potentially favorable TiO2 crystal facets regarding
the inflammatory response and hemostasis are discussed with a view to the advanced surface design
of future implants