Hydrogel swelling: freshly prepared hydrogel samples (200 mg) were freeze-dried and immersed in deionized water (5 mL) at room temperature. At periodic time intervals, the weight of the hydrogels was recorded after removing the surface water. The swelling percentage was calculated as the percentage of weight increase of the swollen state at an interval t (Wt-W0) with respect to the initial weight of the dry hydrogel (W0) (Equation ). Swelling experiments were repeated for three different samples (n=3) and plotted as Mean±SD.