Physical and self–crosslinking mechanism and characterization of chitosan-gelatin-oxidized guar gum hydrogel

The secret of hydrogel formation lies in the intricate chemistry between the constituents and its effective crosslinking. Hydrogels made up of natural polymers have gained immense popularity on account of their biodegradability and biocompatibility. In this work, chitosan–gelatin–oxidized guar gum hydrogel was fabricated with the help of physical and self-crosslinking. Initially, guar gum was exposed to periodate oxidation, and the resultant oxidized guar gum witnessed the transformation of diols into dicarboxylic acids, as validated by Fourier transform infrared spectroscopy. Furthermore, the hydrogel chemistry was decoded to reveal that the carbonyl functional group of oxidized guar gum participated in self-crosslinking associations with gelatin. Moreover, it was found that β-glycerophosphate was responsible for physical crosslinking and sodium bicarbonate decreased the charge density by deprotonation and facilitated hydrogen bonding. Notably, different levels of periodate oxidation were carried out, and the corresponding hydrogels were characterized by several ways to draw a comparative analysis between the level of oxidized guar gum and the essential characteristics of the hydrogels, with a major emphasis on hydrogel chemistry.