Multiresponsive hydrogels and organogels based on photocaged cysteine

Rickhoff J, Cornelissen NV, Beuse T, Rentmeister A, Ravoo BJ

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.