Dealloyed nano-porous Ti[sbnd]Cu coatings with controlled copper release for cardiovascular devices

Abstract

TiCu coatings with controlled copper release and nano-porous structures were fabricated as biocompatible, blood-contacting interfaces through a two-step process. Initially, coatings with 58 % Cu were created using HiPIMS/DC magnetron co-sputtering, followed by immersion in a dilute HF solution for varying durations to achieve dealloying. The presence of Ti elements in the as-deposited TiCu coatings facilitated their dissolution upon exposure to the dilute HF solution, resulting in the formation of nanopores and increased nano-roughness. Dealloying treatment time correlated with higher Cu/(Ti + Cu) values, nanopore size, and nano-roughness in the dealloyed samples. The dealloyed TiCu coatings with 87 % Cu exhibited a controlled release of copper ions and displayed nanopores (approximately 80 nm in length and 31.0 nm in width) and nano-roughness (Ra roughness: 82 nm). These coatings demonstrated inhibited platelet adhesion and suppressed smooth muscle cell behavior, while supporting favorable endothelial cell viability and proliferation, attributed to the controlled release of copper ions and the extent of nanostructures. In contrast, the as-deposited TiCu coatings with 85 % Cu showed high copper ion release, leading to decreased viability and proliferation of endothelial cells and smooth muscle cells, as well as suppressed platelet adhesion. The TiCu coatings met medical safety standards, exhibiting hemolysis rates of <5 %. The technology presented here paves the way for the simple, controllable, and cost-effective fabrication of TiCu coatings, opening new possibilities for surface modification of cardiovascular devices such as vascular stents and inferior vena cava filters.