Synthesis and characterization of enzymatically degradable PEG-based peptide-containing hydrogels.

Biodegradable hydrogels were synthesized by the click reaction of 4-arm azido-terminated PEG differing in molecular weight (2,100 and 8,800) and two alkyne-terminated peptides: [alkyne]-GFLGK-[alkyne] and ([alkyne]-GFLG)(2)K. The physical properties of in situ formed hydrogels were examined. The hydrogels were highly elastic as determined by rheological and microrheological studies. Swelling degree and enzymatic degradation by papain were dependent on the molecular weight of the PEG, but not the peptide. For PEG8800-based hydrogels, time-course analysis of degradation showed that the molecular weight of the soluble fraction quickly reached the PEG precursor value. These findings may guide future design of hydrogels with controllable mechanical properties and enzymatic degradability.