Spatially resolved coding of λ-orthogonal hydrogels by laser lithography

A λ-orthogonal reaction system is introduced, where visible light induced radical thiol–ene and UV light induced NITEC (Nitrile-Imine mediated Tetrazole–Ene Conjugation) ligations are consecutively employed to fabricate and functionalize PEG-based hydrogels. The fluorescent pyrazoline cycloadducts from the NITEC reaction are exploited to visualize the written structures within the hydrogels as well as to attach RGD containing functional groups to promote spatially resolved cell attachment on the hydrogel surface.