Investigation of the usability of quercus robur L. extract loaded gelatin and gelatin nanoparticle based alginate/peg hydrogels in diabetic foot ulcer

In patients with Diabetes Mellitus (DM), elevated blood glucose levels cause damage to the nervous system and impair blood circulation. Consequently, chronic wounds such as diabetic foot ulcers (DFUs) develop. Owing to its active constituents with antioxidant, antifungal, antiviral, and antidiabetic properties, Quercus robur L. is utilized in the treatment of patients with DM. Within the scope of this thesis, three different hydrogels incorporating Quercus robur L. were developed and their potential use as wound dressings for DFUs was investigated. The first hydrogel, serving as the control group, was synthesized in the form of a thin film using alginate/PEG/gelatin. The second hydrogel (JNP) was formulated as a thin film composed of gelatin nanoparticles—obtained via a two-step desolvation method—and alginate/PEG/gelatin nanoparticles. The third hydrogel (LJNP) had the same formulation as JNP but was synthesized in sponge form through lyophilization of the prepared gel. According to TEM and DLS analyses, the average particle size of the gelatin nanoparticles was determined to be approximately 100 nm. The antioxidant activities—including superoxide, hydroxyl, and hydrogen peroxide scavenging activities—as well as the antidiabetic activity of the Quercus robur L. extract and the composite films were investigated. The extract was found to be a potent ROS and α-amylase inhibitor. Cell culture studies demonstrated that the hydrogels had no cytotoxic effects on normal mouse fibroblast L929 cells and that hydrogels containing gelatin nanoparticles exhibited higher wound closure rates. Furthermore, these nanoparticle-loaded hydrogels displayed enhanced antioxidant activity. The antibacterial activity of the composite hydrogels was evaluated against S. aureus and E. coli. While the inhibition rates for the gelatin-containing hydrogel were determined to be 5.01 ± 0.34% and 4.62 ± 0.25% against S. aureus and E. coli respectively, hydrogels containing gelatin nanoparticles exhibited 100% inhibition. The in vitro release of Quercus robur L. from the composite hydrogels was examined in pH 7.4 PBS and pH 5.5 acetate buffer for 120 hours, revealing that the cumulative release percentages were similar among the hydrogels.This study proposes, for the first time, that Quercus robur L. extract-loaded composite hydrogels may serve as promising candidates for smart wound dressings for application in DFUs.