Novel Ti-based alloys prepared with different heat treatment strategies as antibacterial biomedical implants

Implant-associated infections are major causes of implant failure. The development of antibacterial alloys with good biocompatibility and sufficient antibacterial properties are highly demanded. Herein, by employing Cu and Mo, we prepared a new Ti-12Mo-5Cu alloy with different heat treatments to control the size and distribution of Ti2Cu crystals. For the solution-treated sample at 750°C (SA750), Ti2Cu could undergo heterogeneous nucleation, whereas for the solution-treated sample at 900°C (SA900), nanoscale Ti2Cu crystals would be widely distributed throughout the alloy via homogeneous nucleation. Interestingly, SA900 presented better antibacterial effect than SA750, with the antibacterial mechanism proposed to be associated with the size and number of Ti2Cu in the obtained alloy. At evidenced by a rabbit osteomyelitis model, it was found that the new alloy had a better antibacterial effect than that of pure Ti. Compared to SA750, SA900 could further reduce the inflammatory reaction and slow the progression of osteomyelitis around the implant, then kept the cortical bone more intact. This study provides a straightforward strategy to control the precipitation of nanoscale Ti2Cu in Ti-12Mo-5Cu, obtaining a new antibacterial alloy with great biocompatibility, corrosion resistance and the ability to induce osteogenesis differentiation, promising for clinical translation.