Seamlessly Integrated Janus-like Artificial Periosteum with Customized Partitioning Structures and Functions for Neurovascularized Osteogenesis.

Natural periosteum features a Janus-like structure with an outer fibrous layer rich in neurovascular networks and an inner osteogenic layer. However, existing artificial periosteum often overlooks the significant differences in structure, mechanical properties, and functions between the two layers, as well as the pivotal role of periosteal neurogenesis in regulating bone formation. Here, we develop a Janus-like periosteum with customized characteristics and biological functions that are similar to those of the two layers of natural periosteum. Highly anisotropic elastic wood chelates Mg2+ via a polydopamine layer, which serves as the outer fibrous layer to trigger neurovascular regeneration. Meanwhile, a ternary liquid crystal (LC) hydrogel with bone extracellular matrix-like characteristics is designed by encapsulating self-assembled chitin whiskers within a tunable PEGDA/PVA semi-interpenetrating network, serving as the inner osteogenic layer. It exhibits good tissue adhesion and osteogenic differentiation capacity. Moreover, a low-viscosity LC hydrogel is infiltrated into the outer layer to form a mortise-and-tenon structure, integrating the two layers into a single unit. This Janus-like artificial periosteum exhibits capabilities in neurogenesis, angiogenesis, and osteogenic differentiation in vitro, as well as promoting neurovascularized bone formation in vivo. This work proposes a study strategy for the biomimetic design of artificial periosteum, providing insights to guide bone regeneration.