Collagenase assay after release studies. After 35 days of incubation at RT, collagenase at a final concentration of 5 U/mL and 5mM CaCl2 was added to the cuvettes with gels. The cuvettes were kept at 25C for the first 4 hours and was then placed at 37C. On day 3, additional collagenase was added to a final concentration of 30 U/mL. The degradation was studied until the hydrogels were completely degraded and photos were taken on day 1, 2, 3 and 6.