Conjugation of methacrylamide groups to a model protein via a reducible linker for immobilization and subsequent triggered release from hydrogels.

An efficient strategy is reported to introduce methacrylamide groups on the lysine residues of a model protein (lysozyme) for immobilization and triggered release from a hydrogel network. A novel spacer unit was designed, containing a disulfide bond, such that the release of the protein can be triggered by reduction. The modified proteins were characterized by MALDI-TOF MS, titration of free NH(2) residues and spectral analysis. The modification reaction is well controlled, and the number of introduced functions can be tailored by changing the reaction conditions. Gel electrophoresis experiments showed that the methacrylamide modified protein can be immobilized in a polyacrylamide hydrogel and subsequently released by reduction of the spacer by which the protein was grafted to the polymeric network.