MECHANICAL BEHAVIOR IN COMPRESSION AND FLEXURE OF BIOACTIVE GLASS (13-93) SCAFFOLDS PREPARED BY ROBOTIC DEPOSITION

摘要

There is a need to develop synthetic scaffolds for repairing large defects in load-bearing bones. Our recent work has shown the ability to create strong porous scaffolds of bioactive glass with a gridlike microstructure by robotic deposition (robocasting) which have compressive strengths comparable to cortical bone. In the present work, the mechanical properties of those 13-93 bioactive glass scaffolds were evaluated in compressive and flexural loading to determine their strength, elastic modulus, and Weibull modulus. The scaffolds had a porosity of ～50%, a glass filament diameter of ～300 μm, and a pore width of ～300 μm in the plane of deposition (xy plane) and -150 μm in z direction. The load in both testing modes was applied in the z direction, and the scaffolds were tested as-fabricated and after immersion in a simulated body fluid (SBF) in vitro. As fabricated, the scaffolds had a strength = 86 ± 9 MPa, elastic modulus = 13 ± 2 GPa, and Weibull modulus - 12 in compression. The strength, elastic modulus, and Weibull modulus in flexure were 11 ± 3 MPa, 13 + 2 GPa, and 6, respectively. The compressive strength and elastic modulus decreased markedly during the first 2 weeks of immersion in SBF, but more slowly thereafter. The consequences of these results for the potential application of this type of bioactive glass scaffold in the regeneration of loaded bone are discussed.