Black phosphorus-loaded anisotropic nanofiber sponges for random skin flaps regeneration

Electrospun nanofibers have been showing their estimable values as tissue engineering scaffolds. Notably, the oriented structure and intelligent responsiveness are significant directions to enhance the application value of the nanofibrous scaffolds. Here, we present a novel 3D anisotropic and responsive nanofiber sponge scaffolds (ARNFSs) loaded with black phosphorus (BP) and vascular endothelial growth factors (VEGF) for random skin flaps regeneration. Aligned polycaprolactone (PCL) nanofibrous mat prepared by electrospinning technology acted as host materials of sponge scaffolds, which were foamed by soaking in sodium borohydride (NaBH 4 ) solution and filled with poly(N-isopropylacrylamide) (pNIPAM) hydrogel. The highly oriented 3D nanofiber sponge scaffolds can guide the growth of cells along the fibers. Utilizing the superior photothermal conversion properties of BP and thermal responsive ability of pNIPAM, VEGF could be controllably released with the irradiation of near-infrared (NIR) light, thus promoting the angiogenesis of random skin flaps. Notably, in vivo experiments have further proved that our 3D ARNFSs have remarkable performance in enhancing the survival of random skin flaps, indicating their significant value in clinical tissue regeneration and other correlative biomedical fields.