Novel porous Ti35Zr28Nb scaffolds fabricated by powder metallurgy with excellent osteointegration ability for bone-tissue engineering applications

Abstract

Titanium (Ti) based porous alloys have been widely used as orthopedic implants. However, the successful applications of these porous Ti alloys need to have the ability to mimic the mechanical properties of natural bone. Novel porous Ti35Zr28Nb scaffolds were fabricated via powder metallurgy (PM), and the fabricated scaffold with 61.1% porosity exhibited favorable mechanical properties with a compression yield strength of 132.5 ± 3.5 MPa and an elastic modulus of 2.9 ± 0.4 GPa, which are desired mechanical properties for bone implant material applications. The extracts of the porous Ti35Zr28Nb scaffolds showed no toxic effect on cell proliferation in vitro and their cytotoxicity grade was at level 0, similar to that of as-cast pure Ti and Ti-6Al-4 V alloy. Additionally, the extracellular alkaline phosphatase (ALP) level of MC3T3-E1 indicated that the bone matrix synthesis on the porous Ti35Zr28Nb scaffolds was slightly higher than that of as-cast Ti-6Al-4 V and pure Ti alloys. After implantation in rat distal femurs for 8 weeks, the porous Ti35Zr28Nb scaffolds were surrounded by new bone tissue, and the numbers of red blood cells, white blood cells, immunocyte cells, and neutrophil cells returned to the normal levels, which indicate that the porous Ti35Zr28Nb scaffolds possess good in vivo osteointegration ability and hemocompatibility. It hence can be concluded that the PM-fabricated Ti35Zr28Nb scaffolds, which have desired mechanical properties and excellent biocompatibility and osteointegration, are a promising candidate alloy for bone-tissue engineering applications in orthopedics.

Keywords: Biocompatibility; Osteointegration; Porous scaffolds; Powder metallurgy; Ti35Zr28Nb alloy.