Digital light processing strength-strong ultra-thin bioceramic scaffolds for challengeable orbital bone regeneration and repair in Situ

Abstract The orbital fracture regeneration and reconstruction is still a catastrophic challenge due to the extremely thin anatomical structure and different defect shapes in various clinical conditions. The conventional biomaterials and preparation technique are often inefficient in satisfying porous scaffold architecture designs with respect to their required structural stability and biological performances. Here we developed the ultrathin scaffolds with high- precision pore structure and appreciable osteogenic activity for orbital bone repair via digital light processing (DLP) stereolithography. The dilute magnesium-substituting wollastonite (CSi-Mg) bioceramic scaffolds of ~1.5 mm in thickness and over 60% in porosity were investigated systematically, and compared with another calcium-magnesium silicate (i.e. akermanite) and the pure wollastonite porous counterparts. The results showed that the flexural strengths (~6−22 MPa) and in vitro biodegradation of such bioceramic scaffolds could be tuned during their chemical composition (i.e. Mg content) design stage, and the CSi-Mg scaffolds were also beneficial for osteogenic cell activity in vitro. In particular, the CSi-Mg scaffolds could readily enhance the new bone ingrowth at 4 weeks of implantation in a critical-sized rabbit orbital bone defect model, and such strength-strong scaffolds exhibited outstanding orbital defect repair efficacy after 12 weeks of implantation, in comparison with the structural instability of other scaffolds. Basically, it is demonstrated that the dilute magnesium doping in wollastonite bioceramic can be favorable for developing the mechanically reliable scaffolds with high porosity and bioactivity but quite thin wall morphology, and meanwhile the DLP-assisted additive manufacturing help us to optimize such porous bioceramic design with respect to their required structural stability for orbital bone reconstruction.