Activated-ester-type photocleavable crosslinker for preparation of photodegradable hydrogels using a two-component mixing reaction.

Photodegradable hydrogels have emerged as powerful platforms for studying and directing cellular behavior in a spatiotemporally controlled manner. Photodegradable hydrogels have previously been formed by free radical polymerizations, Michael-type addition reactions, and orthogonal click reactions. Here, an ester-activated photocleavable crosslinker is presented for preparing photodegradable hydrogels by means of a one-step mixing reaction between the crosslinker and a biocompatible polymer containing amino moieties (amino-terminated tetra-arm poly(ethylene glycol) or gelatin). It is demonstrated that photodegradable hydrogels micropatterned by photolithography can be used to culture cells with high viability and proliferation rates. The resulting micropatterned cell-laden structures can potentially be used to create 3D biomaterials for various tissue-engineering applications.