On the origin of better hemocompatibility of the BCxNyOz coatings

Abstract

The development of hemocompatible coatings on metallic implants is one of the challenges for blood-contacting implantable devices. In this paper, we investigated the blood-material interaction of BCxNyOz coatings deposited on Ti-6Al-4V substrates, using reactive radiofrequency magnetron sputtering technique with variation in nitrogen (N2) flow rate. A series of experiments, including hemolysis tests, erythrocytes, and platelets adhesion and activation analysis, dynamic blood coagulation, and plasma recalcification time tests, were performed to understand the blood-material interactions, qualitatively and quantitatively. The results revealed that the degree of hemolysis on all the samples was below 2.5%, suggesting their favourable interaction with RBCs. The interactions between erythrocytes and platelets with all the BCxNyOz coatings were reduced significantly compared to Ti-6Al-4V. BCxNyOz coatings could substantially delay the time of blood coagulation to the period of 60 min. The plasma recalcification time of coatings was also increased significantly. An effort has been made to rationalize the difference in hardness or blood compatibility parameters in terms of [N]/[B] or [N]/[C] ratio. The present study conclusively establishes that BCxNyOz coatings can significantly enhance hemocompatibility, thereby opening up a myriad of biomedical applications.