Characterisation of Chitosan/PVA/PVP Crossed- linked Nanofibrous Scaffolds for the Potential Application in Dermal Tissue Engineering

Severe burn injuries lead to significant morbidity and mortality as they are traumatic and affect nearly every organ system. Commonly used clinical practices are early burn lesion removal and skin grafting which have improved outcomes for patients with severe burns by lessening mortality rate and length of hospitalisation (Wood 2014). However, the challenges of sourcing donor site tissue especially as in the case of large burn wounds, and poor healing outcomes, for example, scarring, still remain. Tissue engineering combines science and engineering to create functional tissue and organs to maintain, restore or replace diseased parts of the body (Peltola et al. 2008). The applications of tissue engineering are broad; from aiding the growth of new skin, to the delivery of biologically active molecules such as stem cells and growth factors in order to enhance wound healing and regeneration of skin tissue (Kang et al. 2018). The fundamental goal of dermal tissue engineering is to create new fully functional skin including all skin appendages such as blood vessels, nerves, and sweat glands (Wang et al. 2018). This tool not only aids in healing and regeneration but also to reduce scarring and the long-term consequences associated with having scarred tissue (Chua et al. 2016). The electrospinning technology is a popular choice when it comes to producing nanofibers with large surface area to volume ratios and structural architecture similar to the extracellular matrix (ECM) found in skin tissue. Chitosan is the second most abundant natural biomaterial after cellulose (Schiffman and Schauer 2007) and possesses enticing advantages for use in tissue engineering are due to its intrinsic biocompatibility, biodegradability and high-water adsorption capability. Chitosan based composite nanofibers, blended with carrier polymers polyvinyl alcohol (PVA) and polyvinyl pyyrolidone (PVP) were prepared by the electrospinning method. The blend solutions were characterised before electrospinning using rheology. The synthesised three-dimensional electrospun nanofibrous scaffolds (3DENS) were characterised by SEM, FTIR, degradation, and swelling studies. The biological compatibly of the 3DENS were characterised by MTT and live-dead cell assay using cultured human keratinocytes (HaCaT) and normal human dermal fibroblasts (NHDF) cells lines. The dry weight ratio of materials influences the viscosity and spinnability of the material. 3DENS were successfully fabricated using chitosan, PVA and PVP. The 3DENS mechanical and chemical properties were affected by the varying concentrations of materials. Crosslinking the 3DENS using heat increased the water adsorption capability by increasing the number of functional hydrophilic groups in the 3DENS. Crosslinked 3DENS resisted degradation compared to uncrosslinked 3DENS. The addition of chitosan to PVA/PVP increased the rate of degradation for uncrosslinked and crosslinked scaffolds. All the fabricated 3DENS displayed excellent biocompatibility. Uncrosslinked 3DENS showed better NHDF cell viability than crosslinked 3DENS. However, all 3DENS provided a favourable environment for cell viability and growth for HaCaT and NHDF cells