Piezoelectrically-enhanced composite membranes mimicking the tendinous electrical microenvironment for advanced tendon repair

Tendon injuries, prevalent in clinical settings, predominantly arise from the disruption of the collagen matrix and are typically accompanied by pronounced inflammatory responses and perturbations in the tendon's intrinsic electrical microenvironment. Despite advancements in bridging tendon injuries, few strategies currently target the restoration of the tendon's native electrical microenvironment to facilitate repair. Herein, we fabricated electrospun fibers composed of polycaprolactone (PCL) loaded with dopamine (PDA) modified piezoelectric tetragonal-SrTiO3 (T-SrTiO3) (T-SrTiO3@PCL) for overcoming this problem. The application of PCL based electrospun fibers favours the bridging of tendon injuries by reconstructing the collagen matrix, while the incorporation of piezoelectric T-SrTiO3 simulates the endogenous electrical microenvironment of tendon tissue, with the PDA enhancing the combination between T-SrTiO3 and PCL and thereby further increase piezoelectricity. The therapeutic potential of T-SrTiO3@PCL fibers in tendon repair was evidenced by their ability to modulate the inflammatory response, reduce angiogenesis, and upregulate tendon-specific gene expression, as demonstrated in both in vivo and in vitro experiments. These findings underscore the multifunctional electrospun fibers as a novel strategy for tendon repair, emphasizing the critical structure-function relationship in tendon tissue and recreating a conducive electrical microenvironment for regeneration.