Construction of superhydrophobic pyrolytic carbon by creating a biomimetic cobblestone surface pattern for improved hemocompatibility

Although pyrolytic carbon (PyC) has been extensively used in mechanical heart valves, subsequent thrombus formation threatens patient survival. An effective solution to obtain antithrombotic PyC is to endow the PyC surface with superhydrophobicity. Inspired by native heart valve surface patterns, we for the first time, generated a biomimetic cobblestone pattern on the PyC substrate via laser ablation. For comparison, two other patterns of grating and mastoid were also created. The patterned surface was further modified with fluorosilane to achieve superhydrophobicity. The influence of pattern geometry on wettability, drag reduction, and hemocompatibility were studied. Although the three superhydrophobic PyC surfaces exhibited comparable roughness and superhydrophobicity, the cobblestone patterned PyC surface exhibited fewer adhered platelets and longer thrombin time than others. Our results suggest that the biomimetic cobblestone pattern on PyC offers a promising method of improving the hemocompatibility of PyC heart valves.