Well-aligned chitosan-based ultrafine fibers committed teno-lineage differentiation of human induced pluripotent stem cells for Achilles tendon regeneration.

Physical property of substrates such as stiffness and topography have been reported to induce mesenchymal stem cells differentiation into bone, muscle and neuron lineages. Human-induced pluripotent stem cells (hiPSCs) are a highly promising cell source for regenerative medicine. However, physical properties have not yet been reported to successfully induce pluripotent stem cells into specific lineages. This study aimed to develop a robust, stepwise topographic strategy to induce hiPSCs differentiate into teno-lineage. A novel spinning approach termed stable jet electrospinning (SJES), is utilized to fabricate continuous well-aligned ultrafine fibers (891 ± 71 nm), which mimic the native tendon's microstructure and mechanical properties. hiPSCs are first differentiated into MSCs on smooth plastic surface as confirmed by the differentiations into three mesenchymal lineages and expression of characteristic MSC surface markers through an EMT (Epithelial-Mesenchymal Transition) process. Subsequently, the hiPSC derived MSCs are seeded onto well-aligned fibers to differentiate into tenocyte-like cells through activating mechanic-signal pathway. The in situ tendon repair study further confirms that aligned fiber scaffold with hiPSC-MSCs had significant effect on improving the structural and mechanical properties of tendon injury repair. These findings indicate that the stepwise physical substrate change strategy can be adopted to induce hiPSCs differentiation for tendon tissue regeneration.