3D printed HA/GO/sodium alginate composite scaffolds with enhanced mechanical performance and antibacterial activity...

The design of scaffolds for bone repair remains a multidisciplinary challenge, requiring an effective balance between interconnected porosity, mechanical performance, and biological functionality. In this context, the combination of natural polymers with bioactive ceramics has emerged as a promising strategy. In this work, composite scaffolds composed of hydroxyapatite (HA), sodium alginate (Na-alg), and graphene oxide (GO) were fabricated by material extrusion 3D printing. GO was incorporated at a low concentration (0.245 wt%) directly into the HA/Na-alg ink prior to printing. The addition of GO did not significantly affect the rheological behavior of the ink, enabling the fabrication of scaffolds with high fidelity to the designed geometry. Uniaxial compression testing revealed a significant enhancement in mechanical performance, with compressive strength increasing from 1.2 MPa for GO-free scaffolds to 2.3 MPa for GO-containing scaffolds. The scaffolds exhibited strong inhibition of S. aureus growth for both compositions. Cytocompatibility was assessed using alveolar bone-derived mesenchymal stem cells (aBMSCs) treated with scaffold extracts. Cell viability remained above 70% at 1 and 3 days for both HA/Na-alg and HA/GO/Na-alg scaffolds, with a slight reduction observed at day 7 (∼69% and ∼60%, respectively). Fluorescence staining confirmed well-spread cells with normal morphology and increasing density over 48 h, indicating the absence of cytotoxic effects. Overall, HA/GO/Na-alg composite scaffolds can be successfully produced via material extrusion 3D printing, combining enhanced mechanical performance with antibacterial activity and cytocompatibility, supporting their potential application in bone repair.