The hydrogel degradation was tested by incubating different hydrogels, each corresponding to a point in time, in 1 mL PBS pH=7.4 (control) and in the presence of a reducing agent (10 mM GSH or 10 mM dithiothreitol, DTT). For each time point, 0.5 mL of the media was withdrawn and lyophilized to calculate the weight loss of the hydrogel upon degradation, and the storage and loss moduli of the hydrogel were measured by applying the time sweep test (Figure ). The hydrogel was completely deformed when incubated in a reducing environment: the values of G´ and G´´decreased tremendously. The degradation in DTT was twice as fast as the degradation in GSH, and the hydrogel was able to conserve its mechanical properties in the control medium (Figure 3B and 3C). The degradation was also proven by measuring the weight loss of the hydrogel over time. When the disulfide bonds were reduced, the hydrogel gradually lost the crosslinked network configuration, which allowed for the degraded segments to become soluble in the reducing media. Once the solution was lyophilized, the weight of those segments was calculated and the degradation profile of the hydrogels versus time was plotted (Figure ). The SEM images of freeze-dried hydrogels (10% and 17.5% concentrations) recorded before and after incubation with 10 mM DTT show a deformation in the hydrogel network where the pore's configuration was disrupted; hence, we were able to visualize the consequential degradation of the hydrogel's network (Figure ). BSA during the mixing of the hydrogel's components, as shown in Figure . As for the release profiles, the hydrogel could successfully release the FITC-BSA in a reductive environment with the presence of either 10 mM GSH or DTT in a controlled fashion. The hydrogel barely leached any FTIC-BSA in PBS (<20%), which indicates that the release was due to degradation of the hydrogel backbone, not physical diffusion (Figure ). In another experiment, the hydrogels were only incubated in PBS solution, and after 3 h, a high concentration of GSH or DTT was added to the media to observe the sudden release of FTIC-BSA from the hydrogels. This proved that the release from the hydrogel can also occur on demand (Figure ). In Figure