Swelling rate.
Hydrogel swelling rate characterizes its capacity to absorb aqueous fluids in an in vivo environment, which may be directly associated to the exchange of waste and nutrients. (Peng, 2019). Hydrogel samples were immersed in water and weighed to obtain the four SR curves (Figure 5 ). As a result, each hydrogel swelled a high volume of water during the first hour, independently of the polymeric composition. Then, water absorption slowed down reaching an equilibrium after 4 hours.
Starch-PVA hydrogel, consistent with its rigid appearance and smaller channel diameters, showed lower SR values. On the contrary, starch and starch-CS hydrogels presented similar properties, increasing its weight approximately five times. In the case of starch hydrogel, a tendency to lost water in time was observed; this could be related to a loss of structural integrity (Biduski, 2018). A higher swelling rate, which doubles the values of the other hydrogels, was observed for starch-CS-GA. This property is highly convenient for the absorption of water-dispersed drugs and particles; and also an appropriate feature for exudate incorporation in tissue engineering applications.