A photocleavable linker for the chemoselective functionalization of biomaterials

The functionalization of matrices with ‘‘caged’’ functional groups and their subsequent selective uncaging is a promising approach for generating patterns of bioactive molecules to guide cell growth or recreate in vivo microarchitectures. To date, this has been limited to caged carboxylic acids, amines and thiols, functional groups found within biological systems. We present a bifunctional caged carbonyl linker as an alternative approach for the chemoselective functionalization of biomaterials. This linker was readily coupled to collagen, employed as a model biomaterial, and underwent rapid uncaging in aqueous media upon irradiation with ultraviolet light to yield free carbonyl groups. Modified surfaces proved to be non- adhesive to cells until the chemoselective reintroduction of adhesion following incubation of uncaged carbonyls with gelatin hydrazide, with native gelatin failing to elicit a cellular response.