A bilayer skin-mimicking 3D-printed/electrospun wound dressing incorporating deferoxamine and propolis for angiogenesis-associated wound healing: an in vitro, in ovo, and in vivo evaluation.

Abstract

Bilayer wound dressings can integrate an outer protective barrier with a bioactive wound-contact layer, offering functional stratification that more closely reflects selected epidermal and dermal roles than single-layer dressings. In this study, a bilayer wound dressing was fabricated by combining a propolis-coated 3D-printed (3DP) polycaprolactone (PCL) top layer with a deferoxamine-loaded electrospun PCL/polyvinyl alcohol (PVA) base layer (NF.DFO). The ethanolic propolis (Pr) extract used for dip coating was chemically standardized and showed a total phenolic content of 477 ± 2.53 mg GAE/g extract and a total flavonoid content of 134 ± 5.43 mg QE/g extract. The 3DP layer exhibited a strut diameter of 445.33 ± 16.5 µm, a pore size of 737.53 ± 77.05 µm, and a water contact angle of 98.75°, indicating a hydrophobic barrier surface. The bilayer scaffold showed moderate water uptake, reduced water vapor permeability, a tensile strength of 15.69 ± 2.27 MPa, and an interlayer peel strength of 19.4 ± 2.6 mN/mm, supporting its handling stability and interfacial integrity. DFO release reached 84.5% over seven days under in vitro conditions. In vitro, in ovo, and in vivo evaluations showed cytocompatibility, cell adhesion, antibacterial activity associated with propolis, enhanced early angiogenic-marker response, reduced IL-6 and TNF-α immunopositive densities, improved collagen organization, and faster macroscopic wound closure in the BL group compared with the other tested groups. Overall, the BL scaffold represents a promising preclinical 3D-printed/electrospun wound-dressing platform containing 1 wt% DFO for dry to low-to-moderately exuding wounds; however, further studies are required to confirm vascular maturation, cytokine regulation, and clinical relevance.