In recent years, the porous metal
tantalum, as an ideal orthopedic implant material, has become a rising star in the research of scaffold materials. Compared with other scaffolds, porous tantalum scaffolds are more conducive to the local stability of bone defects and surrounding tissues after implantation due to their close elastic modulus, high porosity, large friction coefficient and good biocompatibility with human cancellous bone. At the same time, porous tantalum has a very similar three-dimensional spatial network structure with human cancellous bone. After osteoblasts, chondrocytes or mesenchymal stem cells are cultured in line with them, the cells can adhere to and proliferate on the surface of the material or in the pores, and have the characteristics of endogenous growth to accelerate bone regeneration. When porous tantalum is combined with corresponding cells, a certain amount of growth factor is added to implant into the bone injury or defect site, which accelerates the repair of bone defect and greatly shortens the wound healing time.
Porous tantalum grafts produce glass carbon skeleton by the polarization of polyurethane foam body and are then processed in multiple stages by tantalum metal chemical deposition. This process produces a tantalum coating consisting of 99% tantalum by weight and 1% glass carbon, with thickness between 40 and 50 m, average pore size between 500 and 600 m, and porosity between 75 and 80%.The porosity and pore size of porous tantalum are better than other traditional porous coatings (30% ~ 40%).
The three-dimensional structure of porous tantalum has internal connectivity with the pores. The elastic modulus (3GPa) of porous tantalum is superior to that of subchondral bone (2GPa) or cancinous bone (1.2GPa), whereas its fracture strength and ultimate strength are higher than that of cortical bone and other bone graft alternatives. Animal experiments show that porous tantalum has high toughness, ductility and corrosion resistance. At the same time, tantalum material has high friction coefficient, which will make it have better mechanical stability. Porous tantalum grafts have excellent biocompatibility in animals without peripheral inflammation.
