Rosemary Ethanolic Extract-Loaded Electrospun Nanofibers as a Bioactive Dressing for Diabetic Wound Healing

Diabetic wounds are characterized by dysregulated reactive oxygen species (ROS), bacterial colonization, and excessive wound exudate. Current chronic wound management follows the TIME framework, in which infection-inflammation control and moisture balance can be addressed through wound dressings. Electrospun nanofibers incorporating plant-derived bioactives, such as rosemary ethanolic extract, offer antioxidant, antibacterial, and pro-healing properties relevant to diabetic wound therapy. In this study, rosemary ethanolic extract-loaded nanofibers were fabricated via electrospinning at 14 kV and 75% relative humidity, with a spinneret-collector distance of 13 cm, a flow rate of 1 mL/h, and a spinneret diameter of 0.83 mm. The pre-electrospinning formulation of nanofibers was evaluated for antibacterial activity by agar diffusion, also nanofiber evaluated for antioxidant activity using the DPPH radical scavenging assay and microbial penetration using Staphylococcus aureus and Staphylococcus epidermidis, and wound closure in streptozotocin-induced mice. The resulting nanofibers exhibited smooth morphology, a green appearance, and an average diameter of 237.51 ± 39.37 nm. Although the nanofibers exhibited an initial hydrophobic surface, they exhibited a high swelling capacity (481.09 ± 4.69%) indicating that water was gradually absorbed into the porous matrix and enabling substantial exudate absorption. Encapsulation efficiency was 86.17 ± 3.02%, and release kinetics followed the Korsmeyer-Peppas model. The rosemary extract-loaded formulation contained 2.067 ± 0.004 mg ascorbic acid equivalent per gram and produced inhibition zones of 20.60 ± 1.65 mm against S. aureus and 19.37 ± 0.64 mm against S. epidermidis. The electrospun nanofibers effectively prevented microbial penetration at 32°C and 37°C. In vivo, the wound-closure area under the curve (AUC) was significantly greater than that of the 0.9% sodium chloride control. Both unloaded cellulose acetate nanofibers and rosemary ethanolic extract-loaded cellulose acetate nanofibers promoted diabetic wound healing compared with the sodium chloride control. Although the rosemary extract-loaded nanofiber showed favorable wound healing outcomes, the present in vivo study did not clearly demonstrate an additional therapeutic benefit of rosemary ethanolic extract over the unloaded nanofiber.