During service, blood compo-
nents are deposited on the
surfaces of prosthetic heart
valves and the risk of a throm-
bosis increases; © panther-
media.net / Michael Kößling
Prosthetic heart valves usually consist of carbon. During service, blood components are deposited on their surfaces and the risk of a thrombosis increases. The function of the heart valves is also limited by the deposits. For this reason, follow-up heart surgery is often unavoidable.
In this project, the prosthetic heart valves are tested in a pumping system outside the human body. In these systems, human blood or blood substitutes are running around in circles. The two overlapping coatings on the heart valves fulfill various purposes: "At first, we apply a magnetic layer", says Cenk Aktas, the head of the program division "CVD/Biosurfaces" at INM – Leibniz Institute for New Materials.
"A sensor which is outside the heart valve transmits the signals of this magnetic layer. Depending on how well the blood flows through, we receive different signals, which give us information about the valves function", continues the project leader. The second layer works as protective layer to prevent the deposition of blood components. "By combining these two layers, we can precisely design the protective layer to optimize longevity of the heart valve ", says the materials scientist Aktas.
The prosthetic valves consist of titan. Both layers are applied one after another. Similar to hot water vapor on the pot lid, the materials precipitate on the titan valve in a very thin, uniform layer. The protective layer consists of adamantine carbon. With a thickness of 100 to 150 nm (millionths of a millimeter), the artificial system is comparable to prosthetic heart valves.
COMPAMED.de; Source: IINM – Leibniz Institute for New Materials