Glutathione-responsive multifunctionalizable hydrogels via amine-epoxy click chemistry

A novel glutathione-responsive hydrogel was synthesized through catalyst-free epoxy-amine 'click' chemistry using PEG-diamine and a redox-responsive diepoxy crosslinker. The chain length of PEG-diamine component was varied to modulate the physical characteristics of thus obtained hydrogels. Hydrogels exhibited degradation upon treatment with glutathione, as evident through visually apparanet gel disolution and rheological measurements. The unreacted epoxy and newly formed hydroxyl groups post-gelation were used as reactive handles to functionalize the hydrogels, as demonstrated through attachment of different fluorescent probes. Finally, it was also established that these hydrogels provide an efficient platform for ligand-directed biomolecular immobilization through anchoring of a fluorescently labelled protein onto the hydrogels.