Niobium can improve corrosion resistance and biocompatibility of implants. As early as 1991, some scholars conducted relevant research and analysis on pure titanium implant and pure niobium implant implanted in rabbit bone. The results showed that the opening torque of pure niobium implant was significantly higher than that of pure titanium implant, and it was speculated that the opening torque of pure niobium implant was probably caused by the more irregular surface morphology of pure niobium implant compared with pure titanium implant. However, more studies are inclined to improve the biocompatibility of titanium alloys by introducing niobium to reduce the precipitation of toxic metals (such as nickel and vanadium) ions in titanium alloys, reduce the elastic modulus of titanium alloys and improve the mechanical strength of implants. Sakai et al. examined the effects of 15 common biomaterial elements on the bioactivity of osteoblast-like cells, and showed that vanadium and nickel were much more cytotoxic than niobium in both granular and ionic form. And in 2020, Russia's Tomsk University of Technology developed a titanium niobium alloy with the closest physical properties to bone tissue, helping to create high-quality implants to effectively repair damaged bones. When the researchers found soft niobium titanium alloys with a niobium content ranging from 5 percent to 50 percent, they found that the titanium alloys with a niobium content of 25 percent had the highest cellular activity. As the niobium content increases, the formation of titanium oxide nanotubes accelerates, said center manager Roman Survignev. Nanotubes grown by electrochemical anodizing can be loaded onto the implant surface prior to surgery for local drug delivery, such as antibiotics or growth factors, because of their hollow structure. By changing niobium content and electrochemical anodizing parameters, the geometric parameters, physical and mechanical properties of nanotubes can be controlled to create implants with specific characteristics that maximize the requirements of clinical objectives.
In terms of surgical defect repair, repair materials and support materials need good ductility, specific strength, wear resistance, corrosion resistance and so on. Due to long-term implantation in human body, biological indicators such as biocompatibility and cytotoxicity of metal materials are also widely concerned by researchers. One of the recent efforts of researchers is to reduce the stress shielding effect by reducing the elastic modulus of metal materials as close as possible to bone tissue. According to relevant studies, adding non-toxic metal element niobium to titanium alloy can effectively reduce the elastic modulus of the alloy and improve the corrosion resistance.
