Isocyanate group containing reactive hydrogels: Facile synthesis and efficient biofunctionalization

Functionalizable hydrogels that are readily accessible and can undergo facile and specific conjugation with various functional molecules are attractive platforms for many biomedical applications. In this study, a series of isocyanate functional group bearing reactive hydrogels were synthesized using photopolymerization of 2-isocyanatoethyl methacrylate (ICEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) in the presence of pentaerythritol tetraacrylate (PETA) crosslinker. Bulk hydrogels were characterized using FTIR, TGA and SEM analyses. Hydrogels were also prepared as flat or micropatterned films covalently bonded onto glass surfaces. The reactive isocyanate groups embedded in the hydrogel undergo facile and efficient functionalization with amine- and thiol-containing molecules. The extent of functionalization of these hydrogels can be adapted by varying the amount of reactive monomer incorporated during the syntheses. Apart from several examples of functionalizations, it is demonstrated that these hydrogels can be easily functionalized with bioactive ligands to enable ligand-directed protein immobilization.