3D bioprinting scaffold of gelatine reinforced-zinc nanoparticles synthesized by green synthesis: Comparative evaluation of mechanical and thermal properties

Abstract

The development of sustainable, biocompatible, and mechanically robust biomaterials is essential for nextgeneration biomedical applications. In this study, zinc oxide nanoparticles (ZnONPs) were synthesized using a green, gelatin-mediated approach and incorporated into gelatin-based bioinks to fabricate 3D-bioprinted composite scaffolds. Structural analyses confirmed the successful formation of crystalline ZnONPs and their uniform dispersion within the gelatin matrix. Mechanical testing demonstrated a clear concentration-dependent enhancement, with Young's modulus, tensile strength, and toughness increasing up to 67%, 67%, and 110%, respectively, in Gel-ZnONPs(5) compared to pristine gelatin. Antibacterial assays revealed strong inhibition against S. aureus and Escherichia coli, with zones reaching 23.1 mm and 20.2 mm, approaching the efficacy of Gentamicin. Cytocompatibility remained high across all tested concentrations, with cell viability consistently exceeding 85%, fulfilling ISO 10,993-5 non-cytotoxicity criteria. The 3D bioprinting process yielded structurally stable scaffolds with precise geometry, demonstrating the synergistic advantages of combining green nanoparticle synthesis with additive manufacturing. Overall, the results highlight Gel-ZnONPs composites as promising candidates for tissue engineering, wound management, and antimicrobial biomedical devices, offering a sustainable strategy to enhance functionality, mechanical integrity, and biological performance in biofabricated materials.