Epidermal and fibroblast growth factor incorporated polyvinyl alcohol electrospun nanofibers as burn wound dressing scaffold

Abstract

The primary concern of wound burn is a failure in wound healing and the transition to a chronic wound. Specifically, in full-thickness burn wound, even though skin autograft is the treatment of choice, it has several drawbacks in the donor site, including repeated transplanting; therefore, a robust wound dressing is still needed. Polyvinyl alcohol (PVA) is a synthetic biodegradable polymer which has been widely employed as an artificial substitute for wound dressing. Epidermal growth factor (EGF) and fibroblast growth factor (FGF) are two prominent growth factors (GFs) that mainly assist wound healing. Therefore, in this study, the incorporation of biomolecules, such as GF, into PVA matrix is deemed necessary to enhance the biological properties of the polymer. Thus, PVA-GFs biologically active scaffold for burn tissue is developed and tested on in vitro human dermal fibroblast cells (HDFs) and in vivo burn models. The scaffold design was fabricated as single, mix and multiple layers of PVA loaded with EGF and FGF by electrospinning technique. The chemical composition, morphological, surface roughness, wettability and mechanical properties of the electrospun nanofibers were characterized. The biocompatibility of different nanofiber scaffolds was assessed through in vitro cell culture with HDFs. The cell viability and attachment were analyzed by MTT assay and FESEM. The fabricated GFs incorporated PVA nanofibers were also evaluated through in vivo studies on a burn wound rat model. Sixty-three male Sprague-Dawley rats were divided into seven groups, control, burn, PVA/EGF (single), PVA/FGF (single), PVA/EGF/FGF (mix), and PVA/EGF-FGF (layers) nanofibers groups which all nanofibers set the ratio at PVA:EGF:FGF, 9.5:0.5:0.5 v/v respectively. On days 7, 14, 21, the wound closure was measured, and tissue samples were obtained, then stained with hematoxylin and eosin (H&E) stain to study the process of burn wound healing histologically. The chemical functionalities of both PVA/EGF/FGF and PVA/EGF-FGF nanofiber membranes were mainly attributed to O–H and N–H bonds. In this study, the morphology of the scaffold showed long protrusion and smooth nanofibers without beads and spray with an average range of 198 - 286 nm fiber diameter. Both PVA/EGF/FGF and PVA/EGFFGF nanofibers manifested decrement in fiber diameter, improved wettability and surface roughness. The Young’s modulus of the electrospun PVA nanofibers incorporated GFs were also observed in between 18 and 20 MPa which were in the range of preferable properties of human skin. The in vitro studies showed no cytotoxic effect of all GFs incorporated PVA nanofibers against HDFs cells and showed the highest HDFs viability and adhesion compared to the PVA control sample. Results from the in vivo studies showed that on the 21st post-burn wound day, the closure rate of the PVA/EGF/FGF and PVA/EGF-FGF nanofibers groups were visualized at 88%- 89%, respectively. The neovascular structure, sebaceous gland, and hair follicles were observed in PVA/EGF/FGF and PVA/EGF-FGF nanofibers groups and appeared more healthy skin at day 21. In conclusion, the PVA/EGF/FGF and PVA/EGF-FGF nanofibers display convergently results with superior PVA/EGF/FGF, which could be projected as a suitable biological burn wound dressing scaffold.