Bioactive and Antimicrobial Patterned Nanofibers Scaffold for Skin Regeneration and Wound Healing

Chronic wounds have created a global burden on the patient and health care systems as<br/>severe non-healed wound complications may lead to limb amputation and quality of life. Current<br/>research on Wound care and skin regeneration has been focused on developing practical<br/>therapeutic approaches for chronic wound management. Specifically, there is a need to create a<br/>wound dressing material that can promote cells growth, migration, and distribution across the<br/>wound area and provide protection. Moreover, they should be able to deliver drugs and bioactive<br/>molecules, which promote wound healing and tissue regeneration. Electrospun nanofibers (NFs)<br/>have shown great potential as functional wound dressing material. Aligned, crossed, and fine<br/>diameter fibers are advantageous for wound healing. In this regard, the present study used<br/>poly(glycerol-sebacate) (PGS) and polycaprolactone (PCL) mixture with benign solvents to form<br/>PGS/PCL electrospun nanofibers (NFs) on ground collector and mesh-like collector. This process<br/>produced randomly aligned PGS/PCL NFs and organized crossed PGS/PCL NFS, which resemble<br/>the basket-mesh pattern of collagen fibrils in the skin tissue. Under the scanning electron<br/>microscope, the fibers collected on the mesh collector showed organized crossed fibers with<br/>smaller diameter distribution than the randomly aligned fibers collected on the ground collector.<br/>Uniaxial mechanical testing indicated that the patterned fibers have significantly improved<br/>mechanical properties. Further elements were added to the structure to promote wound healing<br/>through Hyaluronic acid (HA) coating. To provide antimicrobial property, zinc oxide (ZnO)<br/>nanopowders have been added to the polymers mixture. HA coating was realized through scaffold<br/>surface activation by sodium hydroxide (NaOH) to improve the surface polarity and allow<br/>hydrogen bonding with HA. The ZnO nanopowder was fabricated via the microwave-assisted<br/><br/>5<br/><br/>method. Fourier-transform infrared spectroscopy (FTIR) and Energy-dispersive X-ray<br/>spectroscopy (EDX) have been used to confirm the successful addition of HA and ZnO to the<br/>structure. Water contact angle showed that HA-coating had improved the hydrophilic property of<br/>the scaffold as well as water-up take capacity. In vitro biocompatibility test using fibroblast cell<br/>line L929 indicated that 2% (w/w) ZnO has no cytotoxicity on the cells, and HA-coating promotes<br/>cells viability. In-vitro wound healing assay showed that the scaffold could improve cells<br/>migration to the scratch area, and HA-coating made it more significant. Colony-forming unit assay<br/>(CFU) showed a significate antimicrobial activity of the nanofibers loaded with ZnO after 12 hours<br/>against gram-negative E. coli. Synergistically, the crossed scaffold loaded with ZnO and coated<br/>with HA was proven to have an antimicrobial property and improves cells viability and migration,<br/>which are required for wound healing and skin regeneration.