Blood contacting devices are widely used in modern clinical practice. They allow easy access to the vascular system and are useful for drug delivery or cardiovascular disease treatments. However, these devices suffer from failure due to surface-induced thrombosis. Thrombosis – blood clot formation – can close vessels, disturb blood flow, and cause serious medical conditions. Artificial surfaces can trigger the intrinsic pathway of the blood coagulation cascade and result in fibrin and platelet adhesion and aggregation on the surface. Therefore, many surface modification strategies are investigated to obtain hemocompatibility and antithrombogenic properties.

To obtain antithrombogenic coating we studied the effect of chemical and physical modification on inorganic surfaces (glass and metals). The chemical modification was performed by sol-gel deposition via spin coating. We used various silane monomers functionalized with a zwitterionic group or fluorinated alkyl chains. Zwitterionic materials have a bioinert effect due to their strong hydrophilicity, resulting from electrostatic interactions with surrounding water molecules. This interaction allows the formation of a hydration layer on the surface, which is resistant to protein adsorption. Fluorinated alkyl groups are also promising because of their hydrophobicity properties, which can repel blood and resist blood coagulation.

The physical modification was to alter the topography of the surface. This can change the wettability model of the surface, which can enhance the hydrophobic properties. In addition, previous studies have shown that the micro-roughness of the surface can prevent platelet adhesion and activation.

Preliminary results of sol-gel coatings on glass show high stability and strong adhesion. Our results show a decrease in protein adsorption, as the fluorinated alkyl chain elongates. Furthermore, we have found that the zwitterionic coating has a higher resistance to protein and platelet adsorption compared to the fluorinated coatings. In the future, we will use silica nanoparticles and different surface erosion methods to modify the surface topography.