Osteogenic properties of human mesenchymal stem cells cultured on additively manufactured Ti-6Al-4V samples

Abstract

Annually, hundreds of thousands of hip replacements are performed in the United States alone. This number is expected to increase with an increasing number of motor vehicle accidents and an increasingly active aging population. Existing hip implants can fail due to infection, loosening, dislocation, and fracture. Failed implants require revision surgery which can be expensive and painful and lead to reinfection. A promising bone implant material is Ti-6Al-4V, an alloy of titanium. Ti-6Al-4V is bioinert and unlikely to corrode and degrade. It can also form a TiO2 layer in the body that protects it from corrosion and supports the adhesion of bone matrix materials. In addition, it has favourable mechanical properties due to a lower stiffness compared to that of other bone implant materials, yet it retains a high strength that reduces its risk of fracture. Ti-6Al-4V has been shown to form an interlocking bond with bone, a process known as osseointegration. Additively manufactured 3D porous Ti-6Al-4V scaffolds were designed to further improve the mechanical properties and osseointegration of Ti-6Al-4V scaffolds. This project aimed to study the biocompatibility and osteoinductivity of additively manufactured 3D porous Ti-6Al-4V scaffolds. 2D Ti-6Al-4V surfaces and 3D porous Ti-6Al-4V scaffolds were seeded with osteosarcoma cells and mesenchymal stem cells, respectively. Metabolic activity, calcium deposition, alkaline phosphatase activity, cell adhesion, and expression of osteoblast and osteocyte markers were analyzed. It was determined that 3D porous Ti-6Al-4V scaffolds appear to be biocompatible and osteoinductive; however, the scaffolds need to be further modified to improve the osteoblastic differentiation of cells cultured on their surface.