3D printing of bioactive glass S53P4/sodium alginate sintering-free scaffolds

Abstract

Bioactive glass S53P4 (BG S53P4) has been drawing attention as filling material to promote bone regeneration while also providing the treatment of bone infections. However, there are few reports that have explored this composition as material for scaffold manufacturing to be applied in bone tissue engineering. Scaffolds are known for having an optimal geometry to aid on bone regeneration, increasing the effectiveness of traditional filling materials. Aiming to preserve the glass non-crystalline structure, we report the production of a sintering-free BG S53P4/Na-alg (sodium alginate) scaffold by material extrusion 3D printing. The scaffolds were produced using a high BG S53P4 content (37 vol%) and submersed in calcium chloride to cross-link the sodium alginate as an alternative to the sintering process widely employed in ceramic scaffolds. This work addresses the physical and chemical characterization of the BG S53P4/Na-alg scaffold, as well as its antimicrobial properties against S. aureus, E. coli and C. albicans and the cytocompatibility of MC3T3-E1 cells towards the scaffolds. The BG S53P4/Na-alg ink showed high printability, resulting in scaffolds with a high resemblance to the computational model. The cross-linking process with calcium chloride led to the precipitation of sodium calcium carbonate in the scaffold surface, but the non-crystalline structure of the BG S53P4 was preserved. The scaffolds presented antimicrobial activity against S. aureus, E. coli and C. albicans. Viability of MC3T3-E1 cells grown in the presence of samples extracts increased from 61% after incubation with the 2-days extract to over 100% after incubation with 7 and 14 days extracts. Therefore, the combination of BG S53P4 and sodium alginate showed to be suitable to produce sintering-free scaffolds by material extrusion 3D printing, with promising results to the treatment of bone infections.