Use of flavonoid-supported scaffolds for skin tissue injuries

Pressure ulcers are localized wounds that develop in specific pressure areas of the body, and if left untreated, they can progress into deep wounds that extend to the bone. The aim of this thesis is to produce scaffolds that can be potential candidates for the treatment of stage 2 or 3 pressure ulcers, which not only protect the wound area from external factors but also accelerate skin tissue healing. Antibacterial activity was conferred to the produced scaffolds by incorporating silver nanoparticles (AgNPs). To support skin tissue regeneration and alleviate cellular stress, oleuropein, an antioxidant compound abundantly found in olive leaves, was added to the scaffolds. The surface of the oleuropein-incorporated PCL scaffolds was first treated with argon plasma, and then AgNPs were synthesized in situ. Morphological characterizations of the scaffolds were performed using scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), surface analysis, porosity, and contact angle measurements. The antibacterial and antioxidant activities of the produced scaffolds were also evaluated, and their effects on L-929 fibroblast cell viability were examined. The results indicated that no significant differences were observed in the mechanical strength and FTIR analyses between the groups. However, as the amount of oleuropein incorporated into the scaffolds increased (20, 40, and 60 mg were added), the antibacterial activity also increased, which was attributed to the hydrophilic nature of oleuropein. The release profiles of silver ions and oleuropein from the scaffolds were investigated, and it was observed that both silver ions and oleuropein exhibited a rapid release profile within the first 72 hours. Since AgNPs were not covalently bonded to the surface, a rapid release of silver ions occurred when the scaffolds were placed in the release medium. Oleuropein, being a molecule with hydroxyl groups, has an affinity for water and thus dissolves easily in the release medium. The antibacterial properties of the AgNPs were tested, and it was found that the viability of E. coli and S. aureus bacterial strains decreased by 15% and 20%, respectively. The radical scavenging activities of oleuropein-containing scaffolds were also evaluated, with the group containing 60 mg of oleuropein showing a radical scavenging activity of over 90%. The cell viability studies demonstrated that cell adhesion and proliferation occurred on the scaffolds, with the cell viability in the group containing 60 mg of oleuropein reaching up to 120%. The wound healing test (scratch test) was conducted on the samples, and it was observed that the samples containing oleuropein achieved 100% wound closure at the end of 72 hours, compared to the control group, where the wound closure rate was calculated as 65.74% The antibacterial and antioxidant PCL scaffolds, which were intended to be produced at the beginning of the thesis, were successfully fabricated and analyzed. It is suggested that these scaffolds, with further modifications and additives, could be used as alternatives for the treatment of various skin tissue wounds.