Titanium dioxide nanotubes promote M2 polarization by inhibiting macrophage glycolysis and ultimately accelerate endothelialization.

Titanium has been widely used in prosthetic valves, but they are associated with serious defects in titanium-based prosthetic valves, such as thrombosis, calcification, and decay. Therefore, it is very important to biofunctionalize titanium-based valves to reduce inflammation and accelerate endothelialization of stents and antithrombosis. The titanium dioxide nanotubes were prepared from pure titanium (Ti) by anodic oxidation method in this study. The effects of titanium dioxide nanotubes on the metabolism of macrophages and the inflammatory reaction as implants were studied in vitro. The polarization state of macrophages and the ability to accelerate endothelialization were analyzed. The results demonstrated that titanium nanotubes promote M2 polarization of macrophages by inhibiting glycolysis and activating the Adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. In general, biofunctionalization titanium with nanotube could inhibit macrophage glycolysis, reduce inflammatory factor release and promote M2 polarization by activating the AMPK signaling pathway. And endothelialization was accelerated in vitro. Our result demonstrated that titanium nanotube could act as a potential approach to biofunctionlize titanium-based prosthetic valves for endothelialization.