Biomimetically Mineralized Alginate Nanocomposite Fibers for Bone Tissue Engineering: Mechanical Properties and in Vitro Cellular Interactions

We report herein the structural and mechanical properties and in vitro cellular response of hydroxyapatite (HAp)/alginate nanocomposite fibrous scaffolds mimicking the mineralized collagen fibrils of bone tissue. The biomimetically " " nanocomposites, fabricated by electrospinning and in situ synthesis strategy, were compared with pure alginate nanofibers and micrometer-level HAp/alginate composite fibers. The tensile strength and elastic modulus of the nanocomposites increased by 79.3 and 158.4%, respectively, compared to those of alginate. The uniform nucleation and HAp nanocrystal growth on the alginate nanofibers resulted in such enhancement of the mechanical properties via a stress-transfer effect. Rat calvarial osteoblasts were stably attached and stretched more extensively on the nanocomposites' surface than on the pristine alginate. The controlled deposition of the HAp nanophase contributed to a much faster cell proliferation rate on the nanocomposites than on the others. The improved structural stability and osteoblast interactions suggest the fibrous nanocomposite scaffold's potential advantages for bone tissue regeneration.