Abstract text (incl. figure legends and references)
One of the most frequently used materials for biomedical applications is titanium oxide (TiO2) in rutile form. However, thrombogenic phenomena, i.e., pathologic clot formation on the implant surface, is still problematic and can lead to many complications if a clot detaches and enter the bloodstream. The clot formation process is governed by the activation and aggregation of platelets. Their behavior is controlled by pre-adsorbed proteins, especially human blood plasma fibrinogen (HPF), and HPF conformation-dependent availability of the specific platelet recognition sites (γ400-411).
The aim of this study was the examination how the crystallographic orientation of the material surface modulates HPF-mediated platelets adhesion. Firstly, atomic force microscopy (AFM) visualization of individual protein molecules revealed distinct HPF conformations (trinodular or globular) depending on the crystal. Furthermore, analysis of AFM-based adhesion forces showed statistically significant changes in surface energies of HPF-covered rutile surfaces, which was linked to HPF conformation. Subsequently, scanning electron microscopy (SEM) and confocal microscopy visualization of platelets demonstrated significant changes in cell adhesion and activation. It has been proved that platelets state is correlated with a conformation of pre-adsorbed HPF and HPF conformation-dependent availability of the γ400-411.
We proposed a new possibility to control HPF conformation, and thus platelet adhesion and activation by adjusting the crystallographic orientation of the underlying material surface. This mechanism is driven by crystallographic orientation-dependent surface energy and wettability. It can contribute to the design and development of anti-thrombogenic titanium-based biomaterials.