The use of nanostructured riboflavin-induced composite biomaterials in tissue engineering

Wound healing is a complex process, and stimulation of the immune system triggers an inflammatory cascade, delaying wound healing. Therefore, the use of wound dressings with antibacterial properties that support wound healing is crucial for healthy and rapid wound healing. The dressing is expected to be biocompatible, biodegradable, non-toxic, antibacterial, possess a physical and chemical structure that can accelerate wound healing, be cost-effective, and have barrier properties. This will prevent inflammation caused by external factors, support the natural wound healing process, and promote tissue healing. This study investigated the potential use of riboflavin-containing polycaprolactone/collagen membranes as wound dressings. By combining biocompatible natural and synthetic polymers, a material that both mimics extracellular matrix and has high strength can be obtained. In addition to the cell viability-enhancing effect of adding riboflavin to the designed wound dressing, it also interacts with light to exhibit antibacterial effects. The aim of this thesis is to select the most appropriate production method by producing riboflavin-containing polycaprolactone/collagen membranes using two different nanomaterial production methods. In the first proposed production method, the membranes were produced using the drop-dry method, using anodic aluminum oxide membranes with periodically arranged nanopores obtained through two-step anodization as molds. Another proposed production method is electrospinning to obtain nanofiber-structured membranes. Polycaprolactone/collagen and polycaprolactone/collagen/riboflavin materials were obtained using both production methods. The morphological characterization of the produced membranes was performed using atomic force microscopy and scanning electron microscopy, while the chemical composition was characterized using Fourier transform infrared spectroscopy. The in vitro degradation profile of the membranes was then determined. In vitro cytotoxicity and cell proliferation studies were conducted with the L-929 fibroblast cell line, which was selected to investigate the effects of the membranes on cells. The produced materials were found to exhibit over 80% cell viability. However, electrospun PCL/Col/Rb-containing membranes demonstrated increased proliferation and viability. The determination of the antibacterial effect of riboflavin activation with light was also carried out on Staphylococcus aureus and Escherichia coli bacteria, and after white light application of nanopillar PCL/Col membranes containing riboflavin, bacterial viability decreased by 21.95% and 46.96%, respectively, and after white light application of electrospun PCL/Col membranes containing riboflavin, bacterial viability decreased by 20.61% and 47.30%, respectively. The results obtained were applied to rat wound models. The highest healing score was obtained with light-treated nanofiber PCL/Col/Rb materials. By reducing inflammation with light treatment, the highest healing score of 14 was achieved among the experimental groups with the nanofiber PCL/Col/Rb materials, demonstrating a positive effect on healing and the potential for use as a wound dressing in clinical applications.