Freeform Extrusion Fabrication of Titanium Fiber Reinforced Bioactive Glass Scaffolds

Abstract

Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bones is limited due to their low fracture toughness and fairly fast degradation response in vivo. In this paper, we describe our investigation of freeform extrusion fabrication of silicate based 13-93 bioactive glass scaffolds reinforced with titanium fibers. A composite paste was prepared with 13-93 bioactive glass filled with titanium fibers (~16 µm in diameter and aspect ratio of ~250) having a volume fraction of 0.4 vol. %. This paste was then extruded to fabricate scaffolds with an extrudate diameter of about ~0.8 mm. The sintered scaffolds, with and without titanium fibers, had measured pore sizes ranging from 400 to 800 µm and a porosity of ~50%. Scaffolds produced with 0.4 vol. % titanium fibers were measured to have a fracture toughness of ~0.8 MPa•m1/2 and a flexural strength of ~15 MPa. Bioactive glass scaffolds without titanium fibers had a toughness of ~ 0.5 MPa•m1/2 and strength of ~10 MPa. The addition of titanium fibers increased the fracture toughness of the scaffolds by ~70% and flexural strength by ~40%. The scaffolds’ biocompatibility and their degradation in mechanical properties, in vitro were assessed by immersing the scaffolds in a simulated body fluid over a period of one to four weeks.