Artificial heart valves are implanted around 25,000 times a year in Germany because the natural heart valves have been damaged, for example by an infection. The mechanical heart valves are made of titanium oxide, among other things, and last for many years. However, because blood tends to clot on contact with these material surfaces, it is possible for blood clots to form on the surface of the mechanical heart valves. This can be life-threatening if these blood clots detach from the materials. This is why most people with mechanical heart valves take medication for the rest of their lives to reduce blood clotting.
An international research team has now developed a promising approach to significantly reduce blood clotting on the heart valve material titanium. The results of the team from the Universities of Jena, Leipzig and Illinois Urbana-Champaign (USA), led by Jena materials scientist Professor Klaus D. Jandt have now been published in the journal Advanced Healthcare Materials with PhD student Maja Struczynska as first author. The researchers deposited the blood protein fibrinogen on titanium oxide with crystallographically differently oriented surfaces. The coated material surfaces were then exposed to blood platelets (thrombocytes), whose activity, together with fibrinogen, plays a decisive role in the formation of blood clots. Significant differences in platelet activity were observed on the differently oriented material surfaces. While the platelets are very active on so-called (001) titanium oxide surfaces and thus promote blood clotting, the opposite effect was found on (110) surfaces. The reason for this lies in the different behavior of fibrinogen on the material surfaces.
The mechanism for this effect is of a physical nature: fibrinogen adopts a certain folding on the more hydrophobic (110) surface with low surface energy, which in turn restricts the accessibility of the primary amino acid sequences recognized by platelets and thus minimizes their adhesion. There is great potential in applying these materials to heart valves - as this reduces the risk of blood clot formation and the associated complications, thus protecting those affected.
Maja Struczynska, Izabela Firkowska-Boden, Nathan Levandovsky, Reinhard Henschler, Nour Kassir, and Klaus D. Jandt:How Crystallographic Orientation-Induced Fibrinogen Conformation Affects Platelet Adhesion and Activation onTiO2, Advanced Healthcare Materials 2023,
DOI: 10.1002/adhm.20220250
