Robust Silk Fibroin/Bacterial Cellulose Nanoribbon Composite Scaffolds with Radial Lamellae and Intercalation Structure for Bone Regeneration
One big challenge in bone regeneration is preparation of appropriate bone extracellular matrix that mimicks the robust mechanical properties of lamellar structure of natural bones as well as in vivo micro-environment of bone cells. In this work, silk fibroin (SF)/bacterial cellulose nanoribbon (BCNR) composite scaffolds were prepared using various BCNR contents via multi-staged freeze-drying technique. The scaffolds show radial lamellar pattern and gradient lamellae gap distance, the structure, of which can transfer nutrient solution and metabolic waste through capillary effect, and can guide cells from the outer to the inner area of the scaffolds. The gap distance and thickness of the lamellae increased with increasing BCNRs contents. Parts of BCNRs attached to the surfaces of lamellae while others penetrated into it. The intercalation structure led to eight-folded enhancement in compression modulus and six-folded increase in compression strength. This robust three-dimensional composite scaffolds with improved in vitro bioactivity, bone cell adhesion, and proliferation are highly promising for further applications in bone defect repairs.