Gelatin Nanofibers Loaded with Zinc-Doped Hydroxyapatite for Osteogenic Differentiation of Mesenchymal Stem Cells

Tissue engineering of bones often necessitates the addition of exogenous growth factors and supplements to accelerate the differentiation of mesenchymal stem cells to osteogenic lineage, thereby increasing its cost. On the postulation that a scaffold that mimics the micro-/nano-bone architecture per se can provide the essential cues to favor osteogenesis, we developed gelatin nanofibers and loaded them with zinc-doped nano-hydroxyapatite (ZnHp). To further improve its osteogenic potential, the above nano-composite was additionally decorated with rGO platelets (ZnHp@rGO) and incorporated in gelatin nanofibers. On in vitro evaluation, the respective gelatin nanofibers appeared to aid the accelerated differentiation of mesenchymal stem cells toward the osteogenic lineage without the need for any exogenous osteogenic supplement in the milieu. The biomimetic cues provided by ZnHp and ZnHp@rGO also favored angiogenesis, with enhanced CD-31 and iNOS expression. The ability of these nanofibers to induce vascularization was confirmed using an in ovo and in vivo rat model. Apart from its osteoinductive and angiogenic properties, the nanofibers exhibited favorable anti-biofilm activity by preventing the growth of Staphylococcus aureus. Although these results suggest the potential of the scaffold for inducing bone repair in vivo, it also confirms that bones can be engineered at a relatively low cost by designing scaffolds having topographical and biochemical cues that mimic the bone microarchitecture.