Multiresponsive hydrogels and organogels based on photocaged cysteine

Abstract

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.