All-natural ceramic composite bone scaffolds of whitlockite/wollastonite fibers: DLP additive manufacturing, microstructure, and performance

In this study, we introduced a novel approach by using natural calcium phosphate-based ceramic whitlockite as the matrix, natural silicon-based ceramic wollastonite fiber as the secondary phase, and desktop-level DLP 3D printing as the fabrication method to develop an all-natural ceramic porous bone scaffold with excellent mechanical, degradable, biomineralization, and cell responses. The results demonstrated that, at a solid loading of 75 wt% and a sintering temperature of 1000 degrees C, the compressive strength of the whitlockite porous scaffold reached 20.0 MPa. With the incorporation of wollastonite fiber, the compressive strength of the composite ceramic scaffold further increased to 31.0 MPa, achieving a top-tier level for desktop-level DLP-printed porous ceramic bone scaffolds. This mechanical enhancement effect was mainly attributed to the grain refinement effect of WF on whitlockite and the fiber reinforcement effect of WF. Additionally, the degradation rate of the composite ceramic scaffold increased with higher WF content, attributed to the rapid degradation rate of WF and the microstructural changes in the whitlockite matrix induced by WF doping. Furthermore, the biomineralization capability and cellular response of the composite ceramic scaffold were enhanced with WF doping, due to the improved degradation ability promoting the release of calcium, phosphate, and silicon ions. This study further validates the applicability of desktop-level DLP for fabricating ceramic bone scaffolds and provides evidence of the potential of all-natural ceramic whitlockite/WF as bone scaffold materials.