Niobium in porous implants

Porous medical metal implant materials have important and special uses such as treating bone tissue trauma and femoral tissue necrosis. As a porous implant material used for the treatment of bone tissue trauma and femoral tissue necrosis, its porosity should reach 30 to 80%, and it is best for all pores to be connected and evenly distributed, or as needed, the pores are partially connected and evenly distributed, so that it can be connected with The growth of human bone tissue is consistent, and the weight of the material itself is reduced, making it suitable for human body implantation. At present, most of these materials use stainless steel, titanium alloy, tantalum and other metals. As for the refractory metal niobium, due to its excellent biocompatibility and mechanical properties, its porous material is expected to replace the aforementioned traditional medical metal biomaterials and become a biomaterial mainly used for the treatment of bone tissue necrosis. Since metal niobium is harmless, non-toxic and has no side effects to the human body, if it can evenly distribute connected pores and have physical and mechanical properties that are compatible with the human body, it is an important connecting material to ensure the normal growth of new bone tissue. At present, there are few studies on the use of pure niobium as porous implants, while there have been many studies on composite porous implants made by combining niobium and titanium. Xu Jian et al. used powder metallurgy to prepare Ti-25Nb alloys with different porosity. The alloys are then evaluated based on several properties, such as mechanical properties, purity, pore size and porosity. To assess biocompatibility, specimens were subjected to methylthiazoletetrazolium (MTT) colorimetric assay, cell adhesion and proliferation assay using acridine staining, scanning electron microscopy and detection of the inflammatory factor interleukin-6 (IL-6). detection. Experimental results show that the porous Ti-25Nb alloy with connected pores has a pore diameter of 200 to 500 μm, which is conducive to bone ingrowth. The compressive strength of this alloy is similar to cortical bone, while the elastic modulus is closer to cancellous bone. MTT assay showed that the alloy had no adverse reactions to rabbit bone marrow mesenchymal stem cells, and the toxicity was level 0 to 1. Cell adhesion and proliferation experiments showed good cell growth on the alloy surface and in the pores. The alloy did not cause any significant inflammatory response, based on IL-6 levels. It meets the basic requirements for clinical orthopedic implants, giving the alloy good biomedical application prospects. An alloy with 70% porosity has the best mechanical properties, as well as the right pore size and porosity to allow more bone ingrowth.