Freeze-Dried Chitosan Scaffolds Containing Grape Seed Oil for Wound Healing Applications

Wound healing is the ultimate goal in skin repair and tissue engineering. Skin is highly susceptible to injuries, with a mortality rate in chronic wounds comparable to cancers, thus imposing a high cost ($126.8bi/USA) to health care systems. Chronic wound regeneration stagnates in the inflammatory phase, progressing after its control. Porous biomaterials with a tunable degradation that control bleeding and exudate and maintain a moist environment could improve skin repair. Chitosan is biocompatible, biodegradable, antimicrobial, and hemostatic. Vitis vinifera (grape) seed oil (grape seed oil (GSO)) has a high content of unsaturated fatty acids with antioxidant and anti-inflammatory activity. In this study, 0.3% and 0.6% (v/v) GSO were incorporated into chitosan without cross-linker via freeze-drying process aiming scaffolds with enhanced properties for wound healing applications. The porous scaffolds maintained their shape throughout the 28 days in phosphate buffer solution. The overall physical and chemical characterizations showed that GSO was fully incorporated into the chitosan scaffolds (CSs), even after neutralization in NaOH, demonstrating a durable incorporation. Scanning electron microscopy images revealed superficial and interconnected pores in a stratified structure, possibly favorable to cell proliferation and nutrient transport The addition of 0.6% GSO increased porosity by 17%, without altering freeze-drying parameters, possibly by the coalescence of oil droplets during freezing. Moreover, the scaffolds showed high swelling, up to 800%, indicating the potential for exudate control. Higher GSO concentration leads to lower degradation rates in vitro, which is compatible with the wound closure time in chronic wounds. The biological in vitro results showed the high biocompatibility of GSO and the scaffolds in epithelial Vero cells. Altogether, our results show that incorporating GSO in CS using a freeze-drying process allows scaffolds with modulated morphological and physicochemical features, maintaining the biocompatibility of these natural products, making them a promising biomaterial for wound healing.