Aligned electrospun poly(l-lactide) nanofibers facilitate wound healing by inhibiting macrophage M1 polarization via the JAK-STAT and NF-κB pathways

Delayed wound healing remains a challenge, and macrophages play an important role in the inflammatory process of wound healing. Morphological changes in macrophages can affect their phenotype, but little is known about the underlying mechanism. Aligned electrospun nanofibers have natural advantages in modulating cell morphology. Therefore, the current study constructed aligned electrospun nanofibers that could transform macrophages into elongated shapes. Our results demonstrated that aligned nanofibers without exogenous cytokines could downregulate the proinflammatory M1 phenotype and upregulate the prohealing M2 phenotype in an inflammatory environment. Importantly, our study revealed that aligned electrospun nanofibers could inhibit macrophage M1 polarization via the JAK-STAT and NF-κB pathways. Furthermore, the conditioned medium from macrophages cultured on aligned nanofibers could encourage fibroblast migration, proliferation and collagen secretion. In vivo, aligned nanofibers alleviated the inflammatory microenvironment, promoted angiogenesis and accelerated wound healing in mouse skin defects by modulating macrophage phenotypes. Collectively, aligned electrospun nanofibers can influence macrophage polarization via the JAK-STAT and NF-κB pathways and attenuate the local inflammatory response in skin wounds. This study provides a potential strategy to modulate macrophage polarization and promote wound healing by controlling the topology of biomaterials and offers a new perspective for the application of nanotechnology in wound healing. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12951-022-01549-9.