Novel antimicrobial phosphate-free glass–ceramic scaffolds for bone tissue regeneration

In this study a phosphate-free glass–ceramic porous scaffold was synthesized by a three-step methodology involving slurry preparation, induction of porosity by surfactant-assisted foaming following by freeze-drying and sintering. This inorganic scaffold was characterized by X-ray diffraction, scanning electron microscope (SEM), degradation and bioactivity. Thermal treatment at 750 °C showed two new crystalline phases, combeite and nepheline, into the glassy matrix responsible for its properties. The cell response of the scaffold was also evaluated for using as a bone graft substitute. A commercial Biphasic Calcium Phosphate, BCP, scaffold was assessed in parallel as reference material. Microstructures obtained by SEM showed the presence of macro, meso and microporosity. The glass–ceramic scaffold possesses an interconnected porosity around 31% with a crack-pore system that promote the protein adsorption and cell attachment. Glass–ceramic scaffold with high concentration of calcium ions shows an antimicrobial behavior against Escherichia coli after 24 h of contact. Nepheline phase present in the glass–ceramic structure is responsible for its high mechanical properties being around 87 MPa. Glass–ceramic scaffold promotes greater protein adsorption and therefore the attachment, spreading and osteodifferentiation of Adipose Derived Stem Cells than BCP scaffold. A higher calcification was induced by glass–ceramic scaffold compared to reference BCP material.