Multiresponsive hydrogels and organogels based on photocaged cysteine

Here we present the readily accessible amino acid 4,5-dimethoxy-2-nitrobenzyl- l -cysteine (DNC), as an ultra-low molecular weight gelator (MW = 316 g mol −1 ). Sonication of DNC in water or organic solvents as well as pH adjustment in water trigger gelation. A diverse set of stimuli (UV irradiation, oxidation, heat or pH change) induce a gel-sol transition. Moreover, the photo-triggered gel-sol transition was used to obtain a controlled cysteine release from the hydrogel. Photocaged cysteine is a potent gelator for water as well as organic solvents and UV irradiation of these gels leads to controlled release of cysteine.