pH-responsive hydrogels are a type of intelligent material that can respond to solution pH. The unique properties of these hydrogels made them useful in drug delivery, gene delivery, sensors, membrane, and chromatography applications. The aim of this work was to prepare a smart nanocomposite hydrogel based on gelatin, citric acid (as a bio-based cross-linker) and Ag nanoparticles demonstrating pH-dependant properties. Hence, in the present study, nanocomposite hydrogels were successfully prepared via a green solution mixing method using water as solvent, and then their structure was characterized by FTIR spectroscopy. The effect of citric acid concentration (10%, 20% and 30% wt% compared to the polymer matrix), heat treatment of samples and saline concentration as well as pH of solution on the swelling behavior of hydrogels were comprehensively studied. The obtained results showed that all of the samples have a maximum swelling in acidic condition. The developed smart hydrogels in the current study have a high potential for targeted drug delivery applications.
