Fabrication of a gradient hydrophobic surface with parallel ridges on pyrolytic carbon for artificial heart valves

Effective surface modification to endow pyrolytic carbon (PYC) with long-term anti-thrombotic performance is highly demanded. In this work, a gradient hydrophobic surface on PYC was prepared by creating parallel ridges via the combination of laser etching technology and surface fluorosilanization. Scanning electron microscopy (SEM) observation confirms that the gradient hydrophobic surface is composed of a bare PYC region and four regions of parallel ridges with varying distances. The gradient hydrophobic surface is stable in air, phosphate buffer solution (PBS), and flowing PBS. Additionally, the gradient hydrophobic surface on PYC shows spontaneous droplet motion and much lower flow resistance than bare PYC. Compared to bare PYC, the gradient hydrophobic surface on PYC exhibits better blood compatibility and anti-adhesion performance. The results presented in this paper confirm that creating a gradient hydrophobic surface is an effective way of achieving long-lasting anti-thrombosis property.