Wnt3a loaded deformable hydrogel acts as a 3D culture platform for in situ recruitment of stem cells to efficiently repair bone defects via the asymmetric division

Biomaterial-based tissue engineering has emerged as a hotspot in the field of osteanagenesis. Due to invasive operation in the transplantation process always bring irreparable damage to patients, approaches that enable innate repair mechanisms hold considerable promise for bone repair. To this end, a rational design based on in situ recruitment of stem cells is proposed to circumvent the troublesome problem. In this study, an interpenetration network hydrogel is developed utilizing chitosan (CS), in which the enriched bone marrow mesenchymal stem cells (BMSCs) can undergo a tridimensional and freely proliferation. Moreover, the encapsulation of biological growth factor Wnt3a promotes the differentiation of osteoprogenitor cells with an asymmetric cell divisions (ACD) manner, thereby accelerating bone formation. With this "smart biomaterials", a robust instant stem cell ingrowth within the deformable hydrogel and a high efficiency of bone regeneration on a murine skull are observed, both of which are vital for clinical applications. Such an osteoinductive system represents the advanced design concept to repair bone defects effectively, and offers a promising strategy for the development of future bone tissue engineering.