Characterization of TEMPO modified nanocellulose hydrogels and influence of their structure on the rate of nicotine release in water

Na področju biomedicine so vse bolj zanimivi hidrogeli na osnovi naravnih biopolimerov, med katere spada tudi nanoceluloza. V zadnjih letih se raziskovalci ukvarjajo predvsem z uvajanjem takšnih hidrogelov kot dostavni sistem pri zdravljenju raznih bolezni. Pri magistrskem delu sem se ukvarjala s pripravo hidrogelov iz TEMPO-oksidirane nanoceluloze. Za bolj stabilno strukturo in dodatno zamrežitev gela, so bili ti zamreženi z različnimi koncentracijami kalcijevega klorida. Z izvedbo tokovnih testov so bili pridobljeni tudi podatki o vplivu zamreževanja na viskoznost hidrogela. Pridobljeni rezultati so bili opisani s pomočjo Crossovega modela. Na podlagi reoloških meritev pa je bil z Maxwellovim modelom izračunan strižni modul, preko katerega je bila izračunana še gostota zamreženja in velikost hidrogelne mreže. Prav tako sta bili hidrogelom določeni še gostota in poroznost ter njuna povezanost s koncentracijo dodanega kalcijevega klorida. Dobljeni parametri so podali povezavo med karakterizacijo hidrogelov in sproščanjem učinkovin iz hidrogelnih mrež. Pri svojem delu sem spremljala sproščanje nikotina iz hidrogela v vodni medij. S Fickovim zakonom za enodimenzionalni sistem sem določila difuzijski koeficient.Hydrogels based on natural biopolymers, including nanocellulose are becoming interesting in biomedicine. In recent years, researchers have been mainly concerned with the introduction of such hydrogels as a drug delivery systems in the treatment of various diseases. In my master’s thesis I prepared TEMPO-oxidized nanocellulose hydrogels. Hydrogels were crosslinked using different concentrations of calcium chloride to achive more stable structure and higher crosslinking density. By performing viscosity measurements, the effect of crosslinking on hydrogel viscosity was investigated. The obtained results were described by using the Cross model. Based on rheological measurements, the shear modulus were calculate by Maxwell model, through which the crosslinking density and the mesh size of hydrogels were also calculated. The density and porosity of the hydrogels and their relationship to the concentration of added calcium chloride were also determined. The obtained parameters provided a connection between the characterization of hydrogels and the release of molecules from hydrogel networks. In my work I used Fick’s law for one-dimensional system to determine the diffusion coefficient for the release of nicotine into an aqueous medium