Electrospun Bilayer Dressings with Spatiotemporal Tobramycin/FGF1 Release Orchestrate Synergistic Infection Control and Regenerative Healing

As temporary skin substitutes, wound dressings should have multiple functions, such as anti-inflammatory, sterilization, and tissue regeneration-promoting effects. In this study, a multilevel construction strategy was used to construct a bilayer tobramycin (TOB)/acid fibroblast growth factor-coloaded composite functional dressing by electrospinning, emulsification cross-linking, and freeze-drying for sustained drug release and wound repair. The dressing simulated the double-layer structure of the skin, with an upper layer composed of a TOB-loaded poly(lactic-co-glycolic acid)/multiwalled carbon nanotube electrospun membrane, which can prevent body fluid loss, resist external bacterial invasion, and act as a protective barrier, and a lower layer composed of an FGF1-loaded calcium alginate microsphere/chitosan composite sponge with hemostatic, moisturizing, cell proliferation- and tissue regeneration-promoting, and wound healing acceleration functions. The morphology, water contact angle, cell proliferation and migration abilities, antibacterial properties, and angiogenic and coagulation effects of the dressing were determined in vitro, and its skin wound repair properties were evaluated in vivo. The upper layer of the dressing was hydrophobic, whereas the lower layer was hydrophilic. Moreover, the dressing significantly promoted L929 cell proliferation and migration; had strong antibacterial effects on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa; and promoted angiogenesis and the healing of full-thickness skin wounds in Sprague-Dawley (SD) rats, along with possessing good hemostatic properties.