Titanium Dioxide Covalently Immobilized Citric Acid (TiO2-CA) Nanohybrid Coating of Neurovascular Flow Diverter to Improve Antithrombogenic and Pro-Endothelialization Properties

Braided neurovascular flow diverters (FDs) have revolutionized the treatment of aneurysms. However, dual antiplatelet therapy is mandatory for patients with FDs, which increases the risk of adverse side effects like bleeding complications. Surface modification would be of critical relevance to improve the biocompatibility and therefore clinical performance of FDs. Herein, a titanium dioxide (TiO2) covalently immobilized citric acid (CA) nanohybrid coating is fabricated on nitinol (NiTi) braided FDs by liquid phase deposition and dip-coating, to inhibit thrombosis and promote re-endothelialization. The CA molecules are covalently bound onto the pre-deposited TiO2 nanoparticulate coating. The coating has a unique homogenously nanostructured morphology as well as super-hydrophilicity. Both in vitro and in vivo results verify that the coated samples inhibit platelets and fibrinogen adhesion, delay coagulation time, and concomitantly promote re-endothelialization. Such appealing properties are ascribed to the nature of CA and TiO2 per se as well as the nanostructured morphology. The present strategy may not only provide a new avenue to surface-modify braided neurovascular FDs but also shed light on advanced nanohybrid materials for biomedical applications among others.