Electrospun scaffold with bioactive polyurethane shell infused with propolis and starch-hyaluronic acid core: An advanced therapeutic platform for skin tissue engineering

Biological macromolecules such as polysaccharides and proteins, due to their excellent biocompatibility and biodegradability, are ideal for promoting Skin Tissue Engineering (STE) both in vitro and in vivo. In this study, a core-shell electrospun scaffold was fabricated using the coaxial electrospinning method, with Polyurethane (PU) forming the shell and a mixture of Starch (ST), Propolis Extract (PE), and Hyaluronic Acid (HA) forming the core. The scaffold's morphology was characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), confirming the successful formation of a well-defined core-shell structure. The scaffold exhibited a contact angle of 56.7°, reflecting its favorable hydrophilic properties for cellular attachment. Mechanical testing revealed Young's modulus of 8.12 MPa and a strain at break of 46 %, indicating an optimal balance of mechanical strength and elasticity for STE. Antibacterial tests demonstrated that the core-shell structure exhibited strong antimicrobial activity against Staphylococcus aureus and Escherichia coli, making them a potential candidate. Cytotoxicity assessments showed no toxicity, with L929 fibroblast cells demonstrating enhanced adhesion and proliferation on the core-shell structure compared to control samples. These findings suggest that the PU-shell and ST/PE/HA-core electrospun scaffold represents a promising multifunctional platform for advanced STE and regenerative medicine applications.