Remarkable Stability of Glutathione-Based Supramolecular Gel in the Presence of Oxidative Stress from Hydrogen Peroxide.

Low molecular weight 7-methoxy-3-(-nitrophenyl)iminocoumarin () with donor and acceptor groups has been synthesized. The molecule shows typical π-stacking geometry in the crystal structure. In this study, , an achiral small organic molecule, forms a nanostructured supramolecular gel along with a short peptide sequence glutathione (GSH). The self-assembly of the achiral organic coumarin component and chiral biomolecule produces a chiral gel with helical fiber structures. Interestingly, the helicities of chiral gels are controlled by the solvent ratio, where in DMSO and GSH in water has been used. Variation of the solvent ratio from 6:4 to 1:9 for DMSO:HO results in six gels (, , , , and ), where the gel numbers signify the water content ratio. FE-SEM analysis shows gel fibers with right-handed helical structures, which have been further confirmed by circular dichroism (CD) with notable helicity in to . This is the first report of controlled chiral helical nanostructured supramolecular gel formation by a solvent mixture with an organic small molecule and biomolecule. Interestingly, storage modulus (') initially decreases from to and further increases up to . An opposite strain (%) trend was observed among these six gels. These unusual solvent-dependent gel properties have been further applied to monitor the stability of the gels in the presence of hydrogen peroxide (HO), which converts GSH to oxidized glutathione (GSSG) in general. The oxidative stress from HO disrupts to gels, and precipitation occurs. It is noteworthy to mention that GSSG alone cannot form a gel with the molecule and forms a precipitate. Remarkably, on the other hand, to remain as strong gels even after HO treatment. Among all six gels, shows extraordinary stability of gels even after HO treatment.