Osseointegration assessment of extrusion printed Ti6Al4V scaffold towards accelerated skeletal defect healing via tissue in-growth

Abstract

3D printing is an additive manufacturing technique to produce metallic components with controlled pore size, total porosity and pore-connectivity. Selective laser melting (SLM), the most widely used technique to develop such kind of metallic components for bone graft applications, requires a controlled atmosphere for reactive metal powder processing. In this study, a simple extrusion-based 3D printing technique is developed to produce porous Ti6Al4V scaffold under ambient environmental condition to overcome the existing limitation. 3D printed Ti6Al4V scaffold with pore size ~500µm and total porosity ~58% was achieved. The scaffold exhibited ~13% shrinkage after sintering, resulting in strut diameter ~348µm with persistent inter-particle voids. The compressive strength and elastic modulus values are 39.58±4.56MPa and 450±7.21MPa comparable to cancellous bone mechanical properties. In vitro cytocompatibility assessment of scaffold using mesenchymal stem cells revealed extensive cellular coverage on scaffold surface and differentiation towards bone cell lineage. In vivo studies by scaffold implantation in rabbit femur for four weeks and eight weeks exhibited the scaffold's ability to promote osseointegration and tissue integration through bone in-growth evidenced by micro-CT. Therefore, using this simple and cost-effective technique, bone graft substitute scaffolds could be developed as implant for load bearing applications.