3D printed bioactive calcium silicate ceramics as antibacterial scaffolds for hard tissue engineering

Abstract

VAT photopolymerization technology was applied to fabricate three-dimensional (3D) porous β-Ca₂SiO₄ ceramic scaffolds functionalized with graphene oxide (GO) sheets decorated with silver nanoparticles (AgNPs). We achieved this by utilizing commercial resin blends and “customized” resin both loaded with CaCO₃ particles. The dual functionality of the “customized” resin, which serves as both a preceramic polymer and photocurable resin, is exploited. To assess the properties of these ceramics, we carried out an in-depth comparative analysis using a combination of spectroscopic, microscopic and analytical techniques. After annealing at 1200 °C, the as-prepared ceramics achieved a relative density of 65% leading to high compressive strength (≈40 MPa). Importantly, β-Ca₂SiO₄ ceramic scaffolds demonstrated good in vitro bioactivity by promoting hydroxyapatite formation. When subjected to E. coli, scaffolds functionalized with AgNPs/GO showed higher antibacterial activity than their non-functionalized counterparts. Moreover, ceramic scaffolds derived from the “customized” resin exhibited sixfold higher antimicrobial activity than scaffolds made from commercial resin mixtures. To assess biocompatibility, we conducted in vitro studies using mesenchymal stem cells (MSCs) culture. Encouragingly, all bioceramics proved non-cytotoxic and accelerated the proliferative rate of MSCs compared with the control. After 7 days in culture, cells showed a well-spread morphology with no obvious differences, clearly indicating that bioceramic scaffolds actively promote cell adhesion and viability. Overall, due to their interconnected porosity, excellent biomineralization, mechanical, antibacterial and cytocompatibility properties, these 3D-printed scaffolds hold significant promise as candidates for applications in hard tissue engineering.