Anisotropic and robust hydrogels combined osteogenic and angiogenic activity as artificial periosteum

Periosteum possesses unique characteristics such as anisotropic structure and superior osteogenic and angiogenic ability, which plays vital roles in the formation, remodeling and fracture repair of bone. However, the development of artificial periosteum with such highly desired characteristics is still a challenge. Here, we exhibit the strong and anisotropic chitin composite hydrogels that are composed of chitin chains and maleation chitin whiskers (mCHWs) via chemical and physical dual cross-linking strategy and the stretching-drying process. Moreover, bioactive deferoxamine (DFO) was chosen to further functionalize this anisotropic composite hydrogel to strengthen its ability of osteogenesis and vascularization. This design endows the as-prepared composite hydrogels with remarkable tensile strength (17.6 +/- 1.4 MPa) and Young's modulus (28.1 +/- 2.2 MPa), which are obviously superior to those of polysaccharide hydrogels according to the most references. More importantly, such composite hydrogels not only can effectively enhance cells adhesion and proliferation, but also have the outstanding capability to facilitate the osteogenesis and angiogenesis of cells. Thus, these anisotropic and robust chitin composite hydrogels show promising application for the artificial periosteum.

Automated summary

Periosteum plays vital roles in bone formation, remodeling, and fracture repair. However, developing artificial periosteum with desired characteristics is challenging. In this study, strong and anisotropic chitin composite hydrogels were developed using a dual cross-linking strategy and the stretching-drying process. These hydrogels showed superior mechanical properties and enhanced cell adhesion, proliferation, osteogenesis, and angiogenesis. The findings suggest promising applications for artificial periosteum.