Mechanical, Antibacterial, and Antibiofilm Properties of Iron Carbide-Doped 3D-Printed Bioactive Glass Scaffolds

The management of large-scale bone defects, particularly in oncological contexts, necessitates scaffolds that provide both structural resilience and protection against recalcitrant infections. In this study, we developed multifunctional 3D-printed magnetic bioactive glass (MBG) scaffolds with a composition of 45SiO2-20Na2O-23CaO-6P2O5-2.5B2O3-1ZnO-2MgO-0.5CaF2, reinforced with 0.4% iron carbide (Fe3C) nanoparticles. Utilizing extrusion-based 3D printing, we engineered scaffolds with three distinct architectures: Grid, Gyroid, and Schwarz D. Structural and phase characterization via X-ray diffraction analysis (XRD), Fourier-transmission infrared spectroscopy (FTIR), and field emission scanning electron microscope (FESEM) confirmed the successful integration of the dopant and the fidelity of the printed geometries. Compressive and compressive-shear tests were conducted to evaluate the strength of MBG scaffolds. Flexural strength and fracture toughness were evaluated through three-point bend tests. The Gyroid structure exclusively exhibited comparatively good mechanical properties, potent antibacterial activity against two antibiotic-resistant bacteria (ARBs) of E. coli and Bacillus spp., and antibiofilm activity. This study demonstrates that the customized TPMS architecture offers a promising strategy for developing next-generation bone grafts capable of thriving in complex, infection-prone clinical environments.