Biomedical, antibacterial, mechanical, and drug-releasing properties of 3D-Printed Al₂O₃-Reinforced akermanite composite scaffolds coated with a simvastatin-loaded carrageenan layer

Akermanite-merwinite ceramic scaffolds, reinforced with up to 5 wt% Al₂O₃ nanoparticles were successfully fabricated using 3D-printing technique. The printed scaffolds were subsequently coated with a simvastatin-loaded carrageenan layer to enable controlled drug release. The pore morphology and percentage were characterized using scanning electron microscope (SEM) and image analyzing technique. The results showed that the incorporation of alumina nanoparticles led to a reduction in pore size (as a result of scaffold shrinkage) from approximately 600 μm-400 μm. Moreover, the addition of alumina significantly enhanced the compressive strength from 3.2 MPa to 6.5 MPa and decreased scaffold brittleness. Bioactivity evaluations in simulated body fluid (SBF) confirmed the formation of hydroxyapatite on all scaffolds after 14 days of immersion. In addition, bio-degradation assessments over a six-week period demonstrated improved structural stability in scaffolds containing Al₂O₃. Furthermore, the MTT assay confirmed increased viability and adhesion of MG63 cells. Antibacterial analyses revealed reduced colonization of Escherichia coli and Staphylococcus aureus in the Al₂O₃-containing scaffolds. Additionally, the carrageenan coating facilitated a sustained and controlled release of simvastatin over time. These findings suggest that the proposed akermanite-merwinite-alumina scaffolds can be a promising candidate for bone tissue engineering applications due to their desirable combination of mechanical strength, bioactivity, biocompatibility and drug delivery capabilities.