Starch based nanocomposite hydrogels with improved properties

Natural polymers are preferred especially in hydrogel synthesis for use in biomedical applications due to their many features such as biocompatibility, biodegradability and non-toxicity. Within the scope of this thesis, it was decided to prepare novel starch gels in order to expand the application area by utilizing the advantages of starch, which is one of the most used natural polymers in hydrogel synthesis. Considering the known effect of Amylose/Amylopectin ratio on starch gels, Hylon VII starch with high Amylose was used for the studies. However, as in hydrogels prepared with many natural polymers, the biggest disadvantage of hydrogels obtained from starch is its low mechanical strength. Within the scope of the thesis, two methods were used to create a mechanism that provides energy distribution in the network structure at the molecular level in order to improve the mechanical strength of starch hydrogels and thus to increase the viscoelastic distribution. Firstly, 8-armed cubic glycidyl-Polyhedral Oligomeric Silsesquioxane (g-POSS) functionalized with epoxy groups, which is a nanostructure unit, was used for the crosslinking of starch and a unique single network nanocomposite gel was obtained. Secondly, in the presence of a single network, a second network structure was formed with 2 different monomers and the double network method was used. The characterization studies of the obtained nanocomposite starch gels were examined in detail with gel fraction, swelling measurements, contact angle, SEM analysis, rheological analyzes and uniaxial compression tensile measurements. For gels with improved mechanical strength, an in vitro release medium was created to be used in protein release applications at the last stage of the study. In this direction, gels were degraded in the presence of a-amylase, which catalyzes starch, and protein release kinetics were compared by providing the same release environment in the absence of a-amylase. For future studies, gels sensitive to a-amylase enzyme with improved mechanical strength show promise as a potential drug delivery system in protein or drug delivery systems.