3D nanocomposite scaffolds have attracted significant attention in bone tissue engineering applications. In the current study, we fabricated a 3D nanocomposite scaffold based on a bacterial polyglucuronic acid (PGU) and sodium alginate (Alg) composite with carbon nanofibers (CNFs) as the bone tissue engineering scaffold. The CNFs were obtained from electrospun polyacrylonitrile nanofibers through heat treatment. The fabricated CNFs were incorporated into a PGU/Alg polymeric solution, which was physically cross-linked using CaCl2 solution. The fabricated nanocomposites were characterized to evaluate the internal structure, porosity, swelling kinetics, hemocompatibility, and cytocompatibility. The characterizations indicated that the nanocomposites have a porous structure with interconnected pores architecture, proper water absorption, and retention characteristics. The in vitro studies revealed that the nanocomposites were hemocompatible with negligible hemolysis induction. The cell viability assessment showed that the nanocomposites were biocompatible and supported bone cell growth. These results indicated that the fabricated bacterial PGU/Alg/CNFs hydrogel nanocomposite exhibited appropriate properties and can be considered a new biomaterial for bone tissue engineering scaffolds.

Bone tissue engineering integrates biomaterials, cells, and bioactive agents to propose sophisticated treatment options over conventional choices. Scaffolds have central roles in this scenario, and precisely designed and fabricated structures with the highest similarity to bone tissue have shown promising outcomes. On the other hand, using nanotechnology and nanomaterials as the enabling options confers fascinating properties to the scaffolds, such as precisely tailoring the physicochemical features and better interactions with cells and surrounding tissues. Among different nanomaterials, polymeric nanofibers and carbon nanofibers have attracted significant attention due to their similarity to bone extracellular matrix (ECM) and high surface-to-volume ratio. Moreover, bone ECM is a biocomposite of collagen fibers and hydroxyapatite crystals; accordingly, researchers have tried to mimic this biocomposite using the mineralization of various polymeric and carbon nanofibers and have shown that the mineralized nanofibers are promising structures to augment the bone healing process in the tissue engineering scenario. In this paper, we reviewed the bone structure, bone defects/fracture healing process, and various structures/cells/growth factors applicable to bone tissue engineering applications. Then, we highlighted the mineralized polymeric and carbon nanofibers and their fabrication methods.