Surface treatment of 3D printed porous Ti6Al4V implants by ultraviolet photofunctionalization for improved osseointegration

Three-dimensional (3D)-printed porous Ti6Al4V implants play an important role in the reconstruction of bone defects. However, its osseointegration capacity needs to be further improved, and related methods are inadequate, especially lacking customized surface treatment technology. Consequently, we aimed to design an omnidirectional radiator based on ultraviolet (UV) photofunctionalization for the surface treatment of 3D-printed porous Ti6Al4V implants, and studied its osseointegration promotion effects in vitro and in vivo, while elucidating related mechanisms. Following UV treatment, the porous Ti6Al4V scaffolds exhibited significantly improved hydrophilicity, cytocompatibility, and alkaline phosphatase activity, while preserving their original mechanical properties. The increased osteointegration strength was further proven using a rabbit condyle defect model in vivo, in which UV treatment exhibited a high efficiency in the osteointegration enhancement of porous Ti6Al4V scaffolds by increasing bone ingrowth (BI), the bone-implant contact ratio (BICR), and the mineralized/osteoid bone ratio. The advantages of UV treatment for 3D-printed porous Ti6Al4V implants using the omnidirectional radiator in the study were as follows: 1) it can significantly improve the osseointegration capacity of porous titanium implants despite the blocking out of UV rays by the porous structure; 2) it can evenly treat the surface of porous implants while preserving their original topography or other morphological features; and 3) it is an easy-to-operate low-cost process, making it worthy of wide clinical application. [Display omitted] •An omnidirectional radiator based on ultraviolet photofunctionalization was invented..•The omnidirectional radiator can evenly treat the surface of the porous implants..•The present method can enhance osteoinetegration of porous Ti6Al4V implants in a convenient way with a low cost. Significance statement: 3D-printed porous Ti6Al4V implants are increasingly used in clinics, and their osteoinduction needs to be further enhanced. However, osseointegration promotion methods suitable for porous implants are far from adequate. We designed an omnidirectional UV radiator for the treatment of porous implants. We found that it could significantly improve the osseointegration capacity of porous titanium implants while preserving their original topography. Furthermore, it is an easy-to-operate low-cost process.