Reactive hydrogels grafted on gold surfaces

Three different strategies for the fixation of stable hydrogel coatings on gold surfaces, by the grafting-to and grafting-from techniques, are described. Monomeric or polymeric disulfide initiators are employed to start the photopolymerization of N-[tris(hydroxy-methyl)methyl]acrylamide (1) under bar via decomposition of azo compounds or via a photoredox system. Different approaches, based on the post functionalization of the poly((1) under bar) films or on copolymerization of reactive monomers with (1) under bar, are employed to bind potential receptor molecules bearing amino or thiol groups as anchor to the hydrogel. Thus, the functionalized coatings should allow the selective binding of particular analyzates. The overall goal is focused on hydrogel films for the preparation of biochips used in analytical devices such as Surface Plasmon Resonance (SPR), though our approach seems to be generally useful for related purposes.