Synthesis and Physicochemical Characterization of End-Linked Poly(ethylene glycol)- co -peptide Hydrogels Formed by Michael-Type Addition

The synthesis of novel hybrid hydrogels by stepwise copolymerization of multiarm vinyl sulfone-terminated poly(ethylene glycol) macromers and alpha-omega cysteine oligopeptides via Michael-type additions is described. Cross-linking kinetics, studied by in situ rheometry, can be controlled by pH and the presence of charged amino acid residues in close proximity to the Cys, which modulates the pK(a) of the thiol group. These end-linked networks were characterized by their equilibrium swelling in water, by their viscoelastic properties in the swollen state, and by their soluble fraction. It was demonstrated that structure and properties are very sensitive to the preparation state including stoichiometry and…