Research progress on Ti-Cu alloys regulating macrophage polarization

As a new type of antibacterial material, copper-containing titanium alloys have good biological and mechanical properties and are expected to be widely used in clinical orthopedics and dental implants. Macrophages are the main cells that mediate the immune response after the alloy is implanted into the human body, and they directly affect the stability of the alloy in long-term service. Due to the addition of copper, the copper-containing titanium alloy gives the alloy antibacterial properties. On the one hand, this promotes the phagocytosis of macrophages and kills bacteria. On the other hand, copper promotes the polarization activation of macrophages, which then express a variety of cytokines and trigger inflammation in the body. However, at present, there is no definitive conclusion about the type of copper-containing titanium alloys that regulate the polarization of macrophages, and the mechanism of copper ions regulating the polarization of macrophages is still not fully clear. This article summarizes the published studies on the regulation of macrophage polarization by copper-containing titanium alloys and reviews the relevant literature in terms of material types, surface treatments, processing methods, cell culture methods, and culture density. The application of medical copper-containing titanium alloys has prospects. It is hoped that by changing the properties of copper-containing titanium alloys, such as the processing methods or surface treatments, the polarization direction of macrophages can be adjusted, with a view to the design and clinical application of medical copper-containing titanium alloys.