Fiziksel Çapraz Bağlı Antimikrobiyal Poli(vinil alkol) Hidrojellerinin Sentezi

Abstract

The main objective of this thesis is to synthesize polysaccharide- enriched PVA-based hydrogels as a suitable and environmentally friendly alternative for biomedical applications in accordance with green chemistry principles, and to investigate the potential and antimicrobial properties of the hydrogel structures as a controlled release system by loading antimicrobial agents into the hydrogel structures. Within the scope of the thesis study, the synthesis of hydrogels was carried out with the freeze-thaw technique, which is a physical cross-linking method, aiming for minimum chemical use for the environment in line with the principles of green chemistry. In the studies, the optimum swelling values and mechanical strengths of the hydrogels were investigated by adding sodium alginate (SA), ksantan Gam (XG), guar gam (GG) polysaccharides to the structure of PVA hydrogels, which are ideal for this technique, and a significant increase was achieved in both mechanical strength and swelling capacity. In addition, it should be noted that these polysaccharides not only improve physical properties but also offer important advantages such as biocompatibility and reliability. SA is a biopolymer used in wound dressings, drug delivery systems and tissue engineering applications, and it is known to be used as a thickener in food products. While XG is preferred as a stabilizer and gel former in biomedical and pharmaceutical fields, it is used in the food sector to provide consistency and structural integrity in gluten-free products. GG, on the other hand, draws attention with its controlled drug release and bio adhesion properties and is frequently used in the food sector. Common features of these polysaccharides include their biocompatibility, their resistant structure to environmental factors and their non-accumulation in the body. Integrating SA, XG and GG polysaccharides into PVA-based hydrogels offers the potential for reliable use in biomedical applications as well as improving the mechanical and swelling performance of the material. The main parameters that determine the swelling behavior and mechanical properties of hydrogels synthesized by physical crosslinking are the molecular weight of PVA, the number of freeze-thaw cycles, and the type and amount of polysaccharides used. By optimizing these parameters, PVA-based hydrogels with ideal properties were obtained. The synthesized hydrogels were characterized by mass swelling tests and mechanical tests, such as tensile testing, to determine the ideal swelling and mechanical strength of the PVA and polysaccharide-containing PVA-based hydrogels. The characterization of the hydrogels was also performed using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). The PVA-based hydrogels synthesized within the scope of this study were designed based on materials that can be used in biomedical applications. The targeted antimicrobial property was obtained by loading oxytetracycline (OTC), a broad-spectrum antibiotic, into the hydrogel matrix. The release kinetics of OTC integrated into the hydrogel structure were examined under different temperature and pH conditions; and the antimicrobial activity was tested on Staphylococcus aureus, a gram-positive bacterium, and Escherichia coli, a gram-negative bacterium. The findings show that PVA-based hydrogels exhibit a controlled release profile and high activity against the tested bacteria. In conclusion, the polysaccharide-enriched, PVA-based hydrogels synthesized within the study offer a reliable and environmentally friendly alternative, especially to wound dressings and controlled drug delivery systems, with their antibacterial properties, biocompatibility, and environmentally friendly production methods.