A One Pot, One Step Method for the Preparation of Clickable Hydrogels by Photoinitiated Polymerization

Current preparation methods for hydrogels based on redox or photopolymerization of water soluble monomers are simple to use, and flexible, but have the drawback of requiring additional modification steps for tuning or introducing properties for specific purposes. We have devised a simple and rapid synthetic strategy to prepare hydrogels possessing reactive sites to incorporate any molecules of interest by Click Chemistry. The strategy is based on the use of propargyl acrylamide (PAm) as comonomer together with acrylamide (AAm) and N,N'-methylene bisacrylamide (BAAm) as crosslinker in photoinitiated polymerization. With the selective reactivity of photochemically generated free radicals towards acrylic function of PAm, hydrogels with clickable acetylene groups can be prepared in one pot, one step manner. Based on the acetylene functionality, any molecule possessing azide groups can be conjugated onto hydrogel by Click Chemistry as demonstrated on the example of fluoroscent azide functional pyrene.