Effects of zinc silicate additive on the physicochemical properties and cellular behaviors of 3D-printed magnesium phosphate bioceramic scaffolds

Magnesium phosphate (MP) is a promising bone regeneration material, but it lacks the capacity to efficiently stimulate osteogenesis. In this work, zinc silicate (ZS) was used as an additive to modify MP bioceramics, and the MP-ZS composite bioceramic scaffolds with three-dimensional macroporous structure were fabricated by fiber deposition-based 3D printing and subsequent high-temperature sintering. New silicate phase was produced during sintering the MP-ZS bioceramic scaffolds. Incorporation of ZS allowed the MP-ZS scaffolds to have lower porosity and consequently higher compression strength. The MP-ZS scaffolds modified with 5 wt% ZS exhibited the highest compression strength. The MP-ZS scaffolds gradually degraded in the aqueous environment, accompanied by strength loss and pH variation. The MP-ZS scaffolds sustainably released Zn and Si ions, which could enhance cell proliferation and osteogenic differentiation. Overall, the MP-ZS bioceramic composite scaffolds could be considered as a new biomaterial for application in bone regeneration.