3D printing of tree-like scaffolds for innervated bone regeneration

The diversity of phyllotaxis, such as different blade intervals and divergence angles, is the optimal design for matter exchange and information transfer between plants and external environment, which offers beneficial solutions for designing functional materials. Herein, inspired by the phyllotaxis of plants, a tree-like bioceramic (TLB) scaffold was designed as an integrated three-dimensional platform for multicellular delivery and multiple tissue interactions. The leaf blades of the scaffolds sufficiently supported the adhesion, proliferation, and the osteogenic and neurogenic differentiation of mesenchymal stem cells-Schwann cells coculture system. Interestingly, the gradient surface structure of the leaf blades promoted the proliferation and neurogenic differentiation of the coculture system in a thickness-dependent manner. In addition, the tree-like scaffolds with mesenchymal stem cells-Schwann cells coculture exhibited desirable bone regeneration and remarkable nerve regeneration in vivo. The study provides a promising strategy for preparing biomimetic materials with hierarchical structure and multifunctions for innervated bone tissue engineering. To the best of our knowledge, this is the first report of innervated bone regeneration by using a bioceramic scaffold.