Freeform extrusion fabrication of titanium fiber reinforced 13-93 bioactive glass scaffolds

Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bone is limited due to their poor mechanical properties in comparison to human bone. This work investigates the freeform extrusion fabrication of bioactive silicate 13-93 glass scaffolds reinforced with titanium (Ti) fibers. A composite paste prepared with 13-93 glass and Ti fibers (~16 µm in diameter and lengths varying from ~200 µm to ~2 mm) was extruded through a nozzle to fabricate scaffolds (0-90° filament orientation pattern) on a heated plate. The sintered scaffolds measured pore sizes ranging from 400 to 800 µm and a porosity of ~50%. Scaffolds with 0.4 vol% Ti fibers measured fracture toughness of ~0.8 MPa m1/2 and a flexural strength of ~15 MPa. 13-93 glass scaffolds without Ti fibers had a toughness of ~0.5 MPa m1/2 and a strength of ~10 MPa. The addition of Ti 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.