Table 5.

Proline Oligomer (P_n)-Based Oxidation-Responsive Systems

Polymer structure	Formulation	Oxidant	Response to oxidation	Evidence of degradation	Ref.
4% PEG-86% PCL-10% cPCL crosslinked with PEG12-P7-PEG12	Terpolymer scaffolds	1 mM SIN-1, which decomposes into NO and O2− (28 days)	Creation of pores in the polymeric scaffold on oxidative cleavage of proline residues (de-crosslinking)	13.5% greater mass loss than in scaffolds cross-linked with PEG-dihydrazide	(202)
				DSC, ∼5% lower heat capacity for melting point transition attributable to ROS-mediated hydrolysis

cPCL, poly(carboxy-ɛ-caprolactone); DSC, differential scanning calorimetry; percentages indicate molar proportions; PEG, poly(ethylene glycol); PCL, poly(ɛ-caprolactone); SIN-1, morpholinosydnonimine.