Biomineralized Poly(l-lactic-co-glycolic acid)/Graphene Oxide/Tussah Silk Fibroin Nanofiber Scaffolds with Multiple Orthogonal Layers Enhance Osteoblastic Differentiation of Mesenchymal Stem Cells.

Abstract

Bone scaffolds with interconnected pores, good mechanical properties, excellent biocompatibility, and osteoinductivity are challenging to fabricate. In this study, we fabricated and characterized the morphology, hydrophilicity, protein adsorptivity, mechanical properties, and fibrous structure of nanofiber scaffolds with multiple, orthogonal layers of composite materials based on poly(l-lactic-co-glycolic acid) (PLGA), graphene oxide (GO), tussah silk fibroin (TSF), and hydroxyapatite (HA). The data show that incorporation of 1 wt % GO into PLGA/TSF nanofibers significantly decreased the fiber diameter from 321 to 89 nm. On the other hand, incorporation of 10 wt % TSF accelerated the nucleation and growth of HA on composite PLGA/GO scaffolds exposed to simulated body fluid. Furthermore, the compressive modulus and stress of composite scaffolds with GO were 1.7-fold and 0.6-fold higher than those of similar scaffolds without GO. Interestingly, composite scaffolds with multiple orthogonal layers exhibited higher compressive modulus and stress compared to scaffolds with randomly oriented nanofibers. Biological assays indicated that mineralized scaffolds with multiple orthogonal layers significantly enhanced cell adhesion, proliferation, and differentiation of mesenchymal stem cells into osteoblasts. In summary, the data indicate that these scaffolds have excellent cytocompatibility and osteoinductivity and have potential as versatile substrates for bone tissue engineering.