Tendon-like Tissue Regeneration Via an Electrospun Nanofiber Scaffold and Cyclic Stretch Stimulation

Abstract Purpose Tendons have limited intrinsic healing because of their low cellularity. We hypothesized that recreating a tendon-like, unidirectionally aligned extracellular matrix and applying exercise-like mechanical cues are essential for physical and cellular compatibility during tendon regeneration. This study aimed to clarify the relationship between tenogenic induction and tissue-structure changes under mechanical stimulation, using a reproducible aligned nanofiber platform. Methods Unidirectionally oriented nanofibers were fabricated by electrospinning directly onto a silicone-rubber substrate suitable for incubator use and subsequent mechanical stimulation. Nanofiber layers were stacked to increase thickness, and fiber morphology was characterized. Scleraxis-programmed tendon progenitors derived from human mesenchymal stem cells were seeded onto the nanofiber layer. Cell proliferation and tendon-related gene expression were evaluated. Results The aligned nanofiber laminate was fabricated efficiently and reproducibly and reached a thickness of approximately 100 micrometers. Because the laminate was several times thicker than adherent, spread cells, the influence of the substrate’s elasticity and hardness was minimized. The nanofibers had diameters of 0.2 to 1 micrometer, which are smaller than cell size and promote compact adhesion sites and alignment along the fiber direction. Cells cultured on the nanofiber layer exhibited enhanced proliferation without a decrease in tendon cell–specific gene expression. Conclusion A thick, aligned electrospun nanofiber laminate on silicone rubber supports scleraxis-programmed tenogenic progenitors and preserves tendon-related gene expression, providing a practical platform to study structure–cell responses and to apply controlled mechanical stimulation in tendon tissue regeneration.