5. (15pts) You are developing two hydrogel systems for controlled release of a therapeutic growth factor (GF) to aid bone repair. In one system the GF is dispersed throughout a synthetic polymer hydrogel that degrades by hydrolysis. In the second system, the GF is loaded into gelatin microspheres, which are subsequently dispersed throughout the same hydrogel (the GF is only loaded into the microspheres). You measure in vitro release kinetics of the GF in both (1) phosphate buffered saline (PBS and (2) PBS containing collagenase (an enzyme that degrades gelatin). The graphs below illustrate the results of the study. What do the results suggest regarding the GF release mechanism from each system? Hydrogel Samples Hydrogel with Gelatin Microspheres Samples Time Time Enzyme PBS