Usnic‐Acid‐Functionalized Silk Fibroin Composite Scaffolds for Cutaneous Wounds Healing

Abstract

Despite the progress in chronic wound treatment, antibacterial cutaneous scaffold with high efficiency in wound healing is still the hot spot in the field. In present study, a functionalized silk fibroin (SF) cutaneous scaffold incorporated with natural medicine usnic acid (UA) is investigated, in which UA is used as an antibacterial and wound‐healing reagent. Via electrospinning, UA–SF mixture is fabricated into UA–SF composite scaffold (USCS), which is composed of uniform nanofibers with average diameters of around 360 ± 10 nm. The interwoven nanofibers form mesh structure providing sufficient moisture permeability for scaffold. With methanol treatment, USCS presents improved mechanical properties and stability to protease XIV. In the presence of USCS, the growth rate of both Gram‐positive and Gram‐negative bacteria, including Staphylococcus aureus, Streptococci pyogenes, Escherichia coli, and Pseudomonas aeruginosa, is significantly inhibited in plate culture and suspension assays. In a cutaneous excisional mouse wound model, USCS presents a significant increase of wound closure rate, compared with pure SF scaffold and commercial dressing, Tegaderm Hydrocolloid 3M. The histological assessments further prove that USCS can enhance re‐epithelialization, vascularization, and collagen deposition in wound site to promote the wound‐healing process, which indicates the potential application of USCS in chronic wound treatment.

Cutaneous Regeneration Mechanism of β-Sheet Silk Fibroin in a Rat Burn Wound Healing Model

“…These two critical steps are essential for skin regeneration. Our results are consistent with those of previous studies that used SF dressing to improve wound healing [ 20 , 50 , 51 ]; however, previous studies did not focus on the influence of β-sheet SF. This study used 75% ethanol treatment to achieve an α-helix to β-sheet SF transition.…”

“…However, it is difficult for amorphous silk fibroin (α-helix or random coil) to form stable scaffolds [ 16 , 17 ]. β-sheet silk fibroin provides good mechanical properties and structure for cell attachment; moreover, it shows a nontoxic influence on fibroblasts and stem cells [ 18 , 19 ], facilitation in collagen deposition during bone regeneration [ 19 ], and promotion for angiogenesis during wound healing [ 20 ]. For building a structurally stable scaffold and a biomaterial for wound dressing, the β-sheet form SF was prioritized [ 21 , 22 ].…”

Enhancing Wound Healing and Bactericidal Efficacy: A Hydrogel Membrane of Bacterial Cellulose and Sanxan Gel for Accelerating the Healing of Infected Wounds

“…This result showed that the inhibitory effect of the composite membrane on E. coli was inferior to S. aureus , which was in line with prior reports. [ 25 ] The prevailing theory suggests that UA exerts its antibacterial effects by influencing pathways associated with redox reactions and nucleic acid repair, leading to alterations in bacterial metabolic pathways. According to reports, E. coli is equipped with diverse nucleic acid repair mechanisms, including base excision repair, photoreactivation, and recombinational repair, to fortify its resilience against adverse environmental conditions and spontaneous errors.…”

Silk Fibroin Combined with Electrospinning as a Promising Strategy for Tissue Regeneration

“…Skin damage can pose serious health risks to the human body, as the skin functions such as insulation, fluid retention, and protection against external threats can be hampered. [ 92 ] Appropriate wound dressings play a vital role in promoting wound healing and skin tissue regeneration. SF nanofibers have good biocompatibility and mechanical properties.…”