3D printing of gear-inspired biomaterials: Immunomodulation and bone regeneration

It is of significance to construct the immunomodulatory and osteogenic microenvironment for three di-mension (3D) regeneration of bone tissues. 3D scaffolds, with various chemical composition, macrop-orous structure and surface characteristics offer a beneficial microenvironment for bone tissue regen-eration. However, there is a gap between the well-ordered surface microstructure of bioceramic scaf-folds and immune microenvironment for bone regeneration. In this study, a gear-inspired 3D scaffold with well-ordered surface microstructure was successfully prepared through a modified extrusion-based 3D printing strategy for immunomodulation and bone regeneration. The prepared gear-inspired scaffolds could induce M2 phenotype polarization of macrophages and further promoted osteogenic differentia-tion of bone mesenchymal stem cells in vitro . The subsequent in vivo study demonstrated that the gear-inspired scaffolds were able to attenuate inflammation and further promote new bone formation. The study develops a facile strategy to construct well-ordered surface microstructure which plays a key role in 3D immunomodulatory and osteogenic microenvironment for bone tissue engineering and regenerative medicine.Statement of significance center dot A gear-inspired 3D bioceramic scaffold with highly well-ordered surface microstructure was success-fully fabricated through a modified extrusion-based 3D printing technique.center dot The size and shape of the highly well-ordered microstructure could be readily modulated.center dot Taking advantage of good inducing effect of the well-ordered microstructure, the gear-inspired scaf-fold could be used as a satisfactory biomaterial, which could induce M2 phenotype polarization of macrophages and further promoted osteogenic differentiation of bone mesenchymal stem cells in vitro .center dot The gear-inspired scaffold could construct 3D immunomodulatory microenvironment to significantly attenuate inflammation and further promote new bone formation in vivo.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.