Chiral supramolecular hydrogel with controllable phase transition behavior for stereospecific molecular recognition

Abstract Chirality is a basic characteristic in living systems, and therefore stereospecific molecular recognition remains a great challenge. Herein, we report on the enantioselective recognition of tryptophan (Trp) isomers with a chiral supramolecular hydrogel (CSH). The CSH can undergo reversible gel-sol transition at varying temperatures and pH values, resulting in significant changes in its morphologies and discernible differences in UV spectra and electrochemical properties. Next, the CSH gel (CSH–G) and the CSH sol (CSH–S) are used for the stereospecific molecular recognition of Trp isomers, and the CSH–G exhibits higher recognition capability due to its unique three-dimensional (3D) network framework. In addition, the CSH based enantioselective recognition is both temperature- and pH-sensitive, which could be ascribed to the gel-sol transition behavior of the CSH at varying temperatures and pH values. Finally, the exact quantitative analysis of the Trp isomers in non-racemic solutions with the developed CSH-G is demonstrated.