In vitro proteolytic release of cefazolin via collagenase II degradation of GelMA hydrogels at 28 units/mL under 300 rpm agitation at 37 °C. (A) Hydrogel degradation defined as mass loss normalized to initial mass for 5%, 10%, and 15% GelMA and 3 µg, 15 µg, 30 µg, and 90 µg of Cefazolin in 10% GelMA. (B) Hydrogel degradation in mass loss normalized to initial mass for 5%, 10%, and 15% GelMA and 30 µg of Cefazolin in 5% and 15% GelMA. Data are shown as mean ± standard deviation. The experiment was performed once with n = 4. Cumulative release as the percentage of the respective encapsulation efficiencies from GelMA hydrogels. (C) Cumulative release of Cefazolin 3 µg, 15 µg, 30 µg, and 90 µg from 10% GelMA. (D) Cumulative release of Cefazolin 30 µg from 5%, 10%, and 15% GelMA. (E) Total cefazolin released via enzymatic degradation in µg. Data are shown as mean ± standard deviation. Standard deviations that are not distinguishable are too small thus occluded by the symbols. The experiment was performed once with n = 3.