Autonomous living materials and bone-inspired scaffolds motivated by human osteogenic microenvironment mechanisms

The repair of secondary critical bone defects is an international medical challenge. Bone tissue engineering provides methods and technology for bone repair. The bone regeneration mechanism serves as inspiration for the material and structural design of bone tissue engineering scaffolds. In terms of materials, this review draws inspiration from the biological characteristics of host cells in the osteogenic microenvironment (including osteoblast lineage, vascular cell lineage, inflammatory cells, etc.), reviewing the regulatory mechanisms of bone self-healing and proposing autonomous living materials scaffolds which prepared by in-situ manufacturing. Autonomous living scaffolds regulate cell migration, proliferation and differentiation in real time by releasing living cells steadily for long-term. Regarding structure, we review the functional role of natural bone structures in bone homeostasis, providing insights into the design of bone-inspired scaffolds. Due to the conflict between the mechanical properties and bone regeneration ability, this review proposes assembled scaffolds. They can prolong the half-life of living cells, provide mechanical support and attachment points for new bone growth, and autonomously regulate osteogenic microenvironment. The assembled scaffolds have potential to advance the research progress in bone tissue engineering field and pave the way for novel clinical bone repair treatments.