Multiparametric influences of 3D-printed organo-mineral scaffolds on bone regeneration

Abstract

Abstract Background The development of synthetic bone substitutes that equal or exceed the efficacy of autologous grafts remains challenging due to a wide range of factors, including the nature of the bone defect to treated and its environment and the patient’s medical history. This study investigated the impact of the composition, architecture, and bioactive additives of 3D-printed organo-mineral cements on host tissue remineralization. Methods Printable cement pastes were formulated by combining hyaluronic acid and α-tricalcium phosphate or anhydrous trimagnesium phosphate cement precursors. Cementitious scaffolds were printed with rectilinear, triangular and gyroid patterns. After 7 weeks of implantation with or without bone marrow, multiparametric qualitative and quantitative assessments were performed using µCT, SEM, and histology. Results None of the setup strategies was as efficient as autologous cancellous bone graft to repair calvarial defects. Nonetheless, the presence of the scaffolds improved the skull vault closure (independent of the composition or architecture), particularly when the scaffolds were soaked in total bone marrow before implantation. No significant effect of scaffold macroarchitecture was observed on tissue mineralization. Magnesium phosphate-based scaffolds (MgP) seemed to induce higher bone formation than their calcium-phosphate-based (CaP) counterparts. They also displayed quick biodegradation, and sparse remaining material was found after 7 weeks of implantation (vs minor biodegradation for CaP). Conclusions Although further improvements are required to reach clinical settings, this study demonstrated the potential of organo-mineral cements for bone regeneration and highlighted the peculiar properties of MgP-based cements. Future investigations on organo-mineral-based materials should take into consideration the comparative baseline provided by these multiparametric assessments.