Nanofibrous textured silk aerogel with 3D channel arrays and adjustable mechanical properties for bone tissue regeneration

Bone tissue engineering scaffolds are an important means of repairing bone defects, but current solutions do not adequately simulate complex extracellular microenvironment fibrous structures and adjustable mechanical properties. We use template-assisted fiber freeze-shaping technology to construct silk fibroin nanofiber aerogels (SNFAs) with nanofibrous textures and adjustable mechanical properties. The parallel arranged channels, the pores, electrospun nanofibers, and silk protein conformation together constitute the hierarchical structure of SNFAs. Especially, the introduced electrospun nanofibers formed a biomimetic nanofibrous texture similar to the extracellular matrix, providing favorable conditions for cell migration and tissue regeneration. In addition, Young's modulus of SNFAs can be adjusted freely between 7 and 88 kPa. The rationally designed 3D architecture makes SNFAs perfectly mimic the fiber structure of the extracellular matrix and can adjust its mechanical properties to match the bone tissue perfectly. Finally, fiber-containing SNFAs observably promoted cell adhesion, proliferation, and differentiation, accelerating the bone repair process. The bone density in the defect area reached 0.53 g/cm3 and the bone volume/total volume (BV/TV) ratio reached 57 % at 12 weeks, respectively. It can be expected that this kind of tissue engineering scaffold with highly simulating extracellular matrix microenvironment and adjustable mechanical properties will possess broad prospects in the field of bone repair.