title: Study of the mechanical stability and bioactivity of Bioglass(®) based glass-ceramic scaffolds produced via powder metallurgy-inspired technology.
abstract: Large bone defects are challenging to heal, and often require an osteoconductive and stable support to help the repair of damaged tissue. Bioglass-based scaffolds are particularly promising for this purpose due to their ability to stimulate bone regeneration. However, processing technologies adopted so far do not allow for the synthesis of scaffolds with suitable mechanical properties. Also, conventional sintering processes result in glass de-vitrification, which generates concerns about bioactivity. In this work, we studied the bioactivity and the mechanical properties of Bioglass(®) based scaffolds, produced via a powder technology inspired process. The scaffolds showed compressive strengths in the range of 5-40 MPa, i.e. in the upper range of values reported so far for these materials, had tunable porosity, in the range between 55 and 77%, and pore sizes that are optimal for bone tissue regeneration (100-500 μm). We immersed the scaffolds in simulated body fluid (SBF) for 28 d and analyzed the evolution of the scaffold mechanical properties and microstructure. Even if, after sintering, partial de-vitrification occurred, immersion in SBF caused ion release and the formation of a Ca-P coating within 2 d, which reached a thickness of 10-15 μm after 28 d. This coating contained both hydroxyapatite and an amorphous background, indicating microstructural amorphization of the base material. Scaffolds retained a good compressive strength and structural integrity also after 28 d of immersion (6 MPa compressive strength). The decrease in mechanical properties was mainly related to the increase in porosity, caused by its dissolution, rather than to the amorphization process and the formation of a Ca-P coating. These results suggest that Bioglass(®) based scaffolds produced via powder metallurgy-inspired technique are excellent candidates for bone regeneration applications.
authors.affiliation: Department of Chemistry, Materials, and Chemical Engineering 'G. Natta'. Politecnico di Milano, Piazza L. Da Vinci 32, 20131 Milano, Italy. Current address: Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
authors.forename: Elena
authors.initials: E
authors.lastname: Boccardi
authors.forename: Virginia
authors.initials: V
authors.lastname: Melli
authors.forename: Gabriele
authors.initials: G
authors.lastname: Catignoli
authors.forename: Lina
authors.initials: L
authors.lastname: Altomare
authors.forename: Maryam Tavafoghi
authors.initials: MT
authors.lastname: Jahromi
authors.forename: Marta
authors.initials: M
authors.lastname: Cerruti
authors.forename: Louis-Philippe
authors.initials: LP
authors.lastname: Lefebvre
authors.forename: Luigi
authors.initials: L
authors.lastname: De Nardo
mesh_terms: D018786:Bone Substitutes / Q000138:chemical synthesis*; D002516:Ceramics / Q000737:chemistry*; D019245:Compressive Strength; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005898:Glass / Q000737:chemistry*; D006244:Hardness; D006361:Heating / Q000379:methods; D008422:Materials Testing; D008669:Metallurgy / Q000379:methods; D011208:Powders; D013314:Stress, Mechanical; D013718:Tensile Strength; D054457:Tissue Scaffolds
chemical_list: D018786:Bone Substitutes; D011208:Powders; C425330:bioactive glass 45S5