A multifunctional electrospun nanofiber/hydrogel-based pro-healing bilayer dressing as a next generation biomaterial...

Infectious wounds present a significant challenge in healthcare due to the delay in wound healing and associated processes. Improper use of antibiotics makes this situation even worse due to antibiotic resistance. To meet the critical requirements of healing infectious wounds, we report a bilayer dressing (BL) that combines a hydrogel-based layer and an electrospun nanofiber-based layer together to mimic the dermal and epidermal architecture of normal skin. The bilayer dressing is fabricated by combining a chitosan/gelatin nanofiber-based layer (NF) with an ursodeoxycholic acid drug (UDC) and carbon dot (CD) loaded hydrogel (UDC/CDs/H-Gel). The hydrogel is fabricated by Schiff base-based crosslinking of quaternized chitosan (QCS) and oxidized alginate (OA). The integration of NF with UDC/CDs/H-Gel leads to ∼45% increment in tensile strength and ∼48% increment in elongation at break. The BL exhibits a swelling of ∼400% in 36 h, a porosity of ∼75%, and an antioxidant activity of ∼93%. Moreover, as compared to individual NF and hydrogel layers, the BL shows good reactive oxygen species (ROS) scavenging behavior, good hemocompatibility (∼4.5% hemolysis), good hemostatic potential, enhanced cell proliferation ability (130% cell viability of L929 cells), and excellent antibacterial activity with 92% and 88% bactericidal efficacy against E. coli and S. aureus, respectively. The wound healing ability of the BL is further evaluated via scratch assay demonstrating ∼97% wound closure. Overall, the BL possesses multifunctionality and presents itself as a potential candidate for accelerated wound healing.