A new method for the fabrication of 3D printed ceramic scaffolds based on magnetic mesoporous bioactive glass/Al2O3 nanowires for bone tissue engineering applications

Abstract

Bone tissue engineering requires scaffolds that combine superior bioactivity with adequate mechanical properties. Although magnetic mesoporous bioactive glasses (MMBG) are highly recognized for their excellent biological performance and potential utility in hyperthermia treatment applications, their inherent brittleness restricts their use in non-load-bearing applications. This study investigates the fabrication of Al2O3 nanowire-reinforced MMBG scaffolds using a cost-effective direct ink writing (DIW) technique. A novel sol-gel-derived binder was employed to bond the primary glass particles without requiring high-temperature sintering process. The effects of incorporating different concentrations of Al2O3 nanowires (2.5, 5.0, and 7.5 wt) into the MMBG scaffolds were systematically evaluated to determine the optimal reinforcement level. Furthermore, the printed scaffolds were dip-coated three times with the MMBG sol and subsequently recalcined at 700 degrees C to achieve a uniform structure. The amorphous nature and mesoporous architecture of the MMBG were characterized through X-ray diffraction (XRD) analysis and Brunauer-Emmett-Teller (BET). Additionally, the magnetic properties of the MMBG was examined using vibrating sample magnetometry (VSM). To analyze the surface functional groups and illustrate the interactions among the scaffold components, Fourier-transform infrared spectroscopy (FTIR) was employed. Furthermore, the impact of adding Al2O3 nanowires on the compressive strength of the scaffold was also assessed. The resulting scaffolds exhibited hierarchical porous architecture, maintained mesoporosity and an amorphous structure, significantly improved mechanical properties, while also possessing magnetic properties. Specifically, the addition of 7.5 wt Al2O3 nanowires enhanced compressive strength by approximately 216.6 +/- 12 , while preserving a high porosity (>82 ). The scaffolds exhibited excellent bioactivity, cellular responses, including high cell viability (>85 ) as confirmed by MTT assays, robust cell adhesion and spreading observed via SEM, and elevated alkaline phosphatase (ALP) activity, indicating strong osteogenic differentiation. These cellular outcomes highlight the scaffold's biocompatibility and its capacity to promote bone tissue regeneration.