Hydroxyapatite/Silk\nFibroin Composite Scaffold with\na Porous Structure and Mechanical Strength Similar to Cancellous Bone\nby Electric Field-Induced Gel Technology

Repair\nand regeneration of bone tissue defects is a multidimensional\nprocess that has been highly challenging to date. The artificial bone\nscaffold materials, which play a core role, still face the conflict\nthat a biofriendly porous structure will reduce the mechanical performance\nand accelerate degradation. Herein, a multistage porous structured\nhydroxyapatite (HA)/silk fibroin (SF) composite scaffold (e-HA/SF)\nwas successfully constructed by cleverly utilizing electric field-induced\ngel technology. The results indicated that the prepared e-HA/SF scaffolds\npossess biomimetic hierarchical porous structures with a suitable\nporosity similar to that of cancellous bone. The HA nanocrystals were\nuniformly encapsulated in the three-dimensional space of the composite\nscaffold, thus endowing the e-HA/SF composite scaffolds with an enhanced\nmechanical performance. Notably, the maximum compression stress and\nYoung’s modulus of e-HA/SF-2 scaffolds can reach 24.66 ±\n0.88 and 28.91 ± 3.19 MPa, respectively, which are equivalent\nto those of cancellous bone. Such mechanical performance enhancement\nwas previously unattainable through conventional freeze-drying strategies.\nMoreover, the introduction of bioactive nano-HA can trigger the optimal\ncell response in both static and dynamic cell culture experiments <i>in vitro</i>. The e-HA/SF composite scaffold developed in this\nstudy can better balance the conflict between the porous structure\nand mechanical and degradation properties of porous scaffolds.