Reactive magnetron co-sputtering of Ti-xCuO coatings: Multifunctional interfaces for blood-contacting devices

Multifunctional interfaces that promote endothelialisation, suppress the viability of smooth muscle cells (SMCs), prevent the adhesion and activation of platelets, while demonstrating antibacterial activity are of great interest for surface engineering of blood-contacting devices. Here, we report for the first time the high-power pulsed magnetron sputtering (HPPMS)/DC magnetron sputtering (DCMS) co-sputtering of Ti-xCuO coatings that demonstrate this required multifunctionality. The Cu contents and surface chemistry of the coatings are optimized, and the critical role of copper release on the viability of endothelial cells (ECs) and SMCs, platelet adhesion, and antibacterial activities is elucidated. Rutile phase is formed for Ti-xCuO coatings with Cu atomic concentrations in the range of 1.9 to 13.7 at.%. Rutile and nanocrystalline/amorphous structures were determined for the coatings with 16.8 at.% Cu, while an amorphous phase was observed for the coating with 33.9 at.% Cu. The Ti-xCuO coatings with higher Cu contents were more susceptible to corrosion, and the release rates of Cu ions increased with increasing the Cu contents, maintaining a stable releasing state for up to 28 days. The Ti-xCuO coatings with optimum microstructure and Cu contents of 3.1 and 4.2 at.% promoted the viability and proliferation of ECs, suppressed the viability of smooth muscle cells, inhibited the platelet adhesion and activation, and showed excellent antibacterial activities. Such multifunctionality was achieved in one-pot through controlled copper ions release in the presence of titanium oxides such as TiO₂ and Ti₂O₃ on the surface. The Ti-xCuO coatings developed through HPPMS/DCMS co-sputtering are attractive for surface modification of blood-contacting materials such as implantable cardiovascular devices.