Fabrication and characterization of an asymmetric bilayer wound dressing for healing acceleration of full thickness wounds.

Full-thickness wounds have always been one of the serious clinical problems that require a series of highly developed wound dressings to offer structural support, angiogenesis, and tissue regeneration. In the present study, an asymmetric bilayer wound dressing made up of a PVDF microfibrous top layer (TL) and a deferoxamine (Def)-loaded soluplus (Sol)-silk fibroin (SF) nanofibrous bottom layer (BL) was fabricated and characterized. After morphological and physical characterization, it was found that the presence of PVDF microfibrous layer increased tensile strength (from 3.0 ± 0.2 to 6.8 ± 0.5 MPa), elastic modulus (from 35.3 ± 3.0 to 77.9 ± 4.3 MPa), and failure strain (from 52.4 ± 2.9 to 66.8 ± 3.2 %). The swelling capability and biodegradability of the fabricated wound dressing resulted in a sustained release of Def up to approximately 88.1 ± 5.2 % in 168 h. The PVDF/Sol-SF-Def dressing showed high levels of cytocompatibility, and its superior angiogenic potential was confirmed by chicken chorioallantoic membrane assay. Histological examination demonstrated that in vivo full-thickness wounds treated with PVDF/SF-Sol-Def had superior re-epithelialization, increased granulation tissue thickness, enhanced collagen deposition, and increased COL1/COL3 ratio indicative of advanced wound remodeling. Therefore, the bilayer structure with its protective and bioactive properties represents a comprehensive approach toward the treatment of full-thickness wounds.