2.2 Characterization of SilMA hydrogel
2.2.1 Swelling test
The swelling ratio of SilMA hydrogel is evaluated by a weighing method.[18] Firstly, the prepared hydrogel was weighed and recorded as M0. Then, the hydrogel was soaked in deionized water (dd H2O) for 24 h at 37°C. After swelling equilibrium, the hydrogel was collected from dd H2O and excess fluid on the surface was removed with the filter paper, then the hydrogel was weighed again and recorded as Mt. The swelling ratio was calculated as follows: Swelling ratio (%)=(Mt−M0)/M0×100%. Experiments were done thrice per composition.
2.2.2 Degradability test
The prepared hydrogel was soaked in dd H2O to reach swelling equilibrium as described above, weighed as W0. Then, the hydrogel was soaked in 24-well culture plate containing 1.5 mL type II collagenase (Absin, Shanghai, China) solution with the concentration of 0.5 mg/mL (37°C), and taken out at 2, 4, 6, 8, 10, 12, 18, 24, 36, 48, 60 and 72 h, respectively. At each point of time, the filter paper was used to remove the excess liquid on the surface and the hydrogel was weighed as Wt. The degradation ratio was calculated as follows: Degradation ratio (%)=(W0−Wt)/W0×100%. Remaining mass (%)=Wt/W0×100%. Same as swelling test, experiments were done thrice per composition.