Investigation of the antibacterial effect, osteogenic activity, and tracing properties of hydroxyapatite co-doped with Tb3+ and Zn2+

Hydroxyapatite (HA) is a biomimetic biomaterial that has been widely used in bone repair for many years. However, the increased risk of infection after surgery and long-time tracing for the material distribution and degradation during bone reconstruction remain challenges in the clinic. Zinc (Zn) is considered as an indispensable microelement for humans and is characterized with antibacterial action and osteogenic activity. Terbium (Tb), a rare-earth element, emits stable fluorescence under ultraviolet light. Here, Tb³⁺/Zn²⁺ co-doped hydroxyapatite (HA:Tb/Zn) was prepared to synchronously realize the antibacterial effect, osteogenic activity, and long-time tracing property. We found that HA:Tb/Zn had a strong antibacterial effect on both Gram-positive and Gram-negative clinical infectious bacteria, as well as improved osteogenic activity. HA:Tb/Zn also displayed stable green fluorescence in vitro and in vivo, which indicated great potential for recognizing the material changes during the bone reconstruction process. The combination of the ternary functions is of great significance to control the overuse of antibiotics and realize long-time tracing, and provide a versatile design on biomaterials in bone repair.