20.500.12556/DKUM-94266 Razvoj protimikrobnih lastnosti bakterijske nanoceluloze z uporabo bio-osnovanih komponent magistrsko delo Development of antimicrobial properties of bacterial nanocellulose using bio-based components Trajnostnost je trenutno eden izmed najpomembnejših konceptov, kamor sodi načelo zaščite pred izčrpavanjem naravnih virov ter koncept zelene kemije. Z željo po implementaciji le-tega se razvijajo nove tehnologije pridobivanja naravnih materialov, uporaba le-teh ter vpeljava ponovne uporabe odpadnih materialov. Bakterijska nanoceluloza (BC) zaradi skladnosti s tem konceptom ter njenih ugodnih lastnostih pridobiva vse več pozornosti za uporabo. Kljub ugodnim lastnostim pa se pojavlja pomanjkljivost na področju uporabe medicinskih aplikacij ter drugih tehnoloških področij, kjer je zahtevano protimikrobno delovanje, ki ga BC sama po sebi ne izkazuje. V raziskovalnem delu smo se tako osredotočili na modifikacijo BC s protimikrobnimi sredstvi. V ta namen smo si izbrali uporabo kvaternega hitozana (HTCC) ter odpad papirne industrije, ki vsebuje lignosulfonat (O-LS), kar je v skladu s konceptom trajnostnosti. Uporabljen HTCC je bil komercialno pridobljen kemijsko očiščen proizvod, medtem ko smo O-LS uporabili v obliki odpada papirne industrije podjetja Mondi, zaradi česar predvidevamo, da so poleg le-tega v sledovih prisotne še druge kemijske spojine. BC membrane, ki smo jih uporabili za modifikacijo so bile komercialno pridobljene, ki smo jih nadalje pripravili v dveh različnih oblikah – kot membrane in kot niti. Modifikacijo smo potrdili s sledečimi metodami: atenuirana popolna refleksija infrardeče spektroskopije s Fourierevo transformacijo (ATR-FTIR), rentgenska praškovna difrakcija (XRD), potenciometrična titracija, goniometrija, optična mikroskopija, vrstična elektronska mikroskopija (SEM), navzemanje vode (WU),  mehanska testiranja, protimikrobna testiranja. S pomočjo poglobljene analize smo potrdili spremembe v lastnostih BC v odvisnosti od strukture (membrana vs. nit) ter protimikrobno delovanje BC membran za S. aureus in S. epidermidis pri BC membrani modificirani z O-LS ter protimikrobno delovanje za S. aureus pri BC membrani modificirani s HTCC. Protimikrobno delovanje pri BC modificirani s HTCC je zagotovila kvaterna dušikova skupina v molekuli HTCC, pri BC modificirani z O-LS pa prisotnost fenolne spojine (prisotnost obeh smo potrdili z ATR-FTIR analizo). Z modifikacijo smo pridobili ultra čist, trajnostni material s protimikrobnim delovanjem, ki ima potencialno uporabno vrednost v medicini, kot tudi na drugih področjih kjer je tovrstna aktivnost zaželena. Sustainability is currently one of the most important concepts, which includes the principle of protection against the depletion of natural resources and the concept of green chemistry. With the desire to implement this, new technologies for obtaining natural materials, their use, and the introduction of recycling waste materials are being developed. Bacterial nanocellulose (BC) is gaining more and more attention due to its compliance with this concept and its favorable properties. However, despite its favorable properties there is a lack in the field of medical applications and other technological areas where antimicrobial activity is required, which BC itself does not have. In this research work, we have therefore focused on the modification of BC with antimicrobial agents. For this purpose, we decided to use quaternary chitosan (HTCC) and lignosulfonate-containing waste from the paper industry (O-LS), which is in line with the concept of sustainability. The HTCC used was a commercially obtained, chemically purified product, while the O-LS used was in the form of a paper industry waste, which is why we assume that other chemical compounds are also present in trace amounts. The BC membranes used for the modification were commercially obtained and were further processed in two different forms - as membranes and as threads. After modification, the following methods were used to verify the changes before and after BC modification: attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray powder diffraction (XRD), potentiometric titration, goniometry, optical microscopy, scanning electron microscopy (SEM), water uptake (WU), mechanical testing, antimicrobial testing. The in-depth analysis allowed us to confirm the changes in BC properties depending on the structure (membrane vs thread) and the antimicrobial activity of the BC membranes against S. aureus and S. epidermidis in the BC membranes modified with O-LS and the antimicrobial activity against S. aureus in the BC membranes modified with HTCC. The antimicrobial activity of HTCC-modified BC was provided by the quaternary ammonium group in the HTCC molecule, and of O-LS-modified BC by the presence of a phenolic compound (the presence of both was confirmed by ATR-FTIR analysis). Through modification, we obtained an ultra-pure, sustainable material with antimicrobial activity, which has potential utility in medicine, as well as in other areas where such activity is desirable. bakterijska nanoceluloza hitozan lignosulfonat protimikrobne lastnosti bacterial nanocellulose chitosan lignosulfonate antimicrobial properties true true false [K. Ravnjak] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-08-11 20:52:49 2025-09-08 12:12:28 2025-11-13 03:16:25 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (XXI, 75 f.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 2028-09-03 [604.4:615.33]:661.728(043.2) 256905219 MAG_Ravnjak_Katja_2025.pdf MAG_Ravnjak_Katja_2025.pdf 1 F36E2EE81B955AA56707A951B3AA576A acdde70e50315ea14221573665fe66bb7f60933f7a687ce67c2b21b5eb839343 863b7d61-8c77-11f0-9059-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=197790 Fakulteta za strojništvo 0 0 0