Figure 1.

Enzymatic degradation measured using bulk rheology. The degradation reaction is initiated by immersion of a gel in 1 mg mL⁻¹ collagenase solution. Bulk rheology measures the elastic moduli, G′, as a function of time of (a) radical-initiated photopolymerized PEG–norbornene (PEG–N) hydrogels and (b) base-initiated polymerized PEG–maleimide (PEG–M) hydrogels.