Selective Coassembly of Aromatic Amino Acids to Fabricate Hydrogels with Light Irradiation-Induced Emission for Fluorescent Imprint

Abstract

Controlling the structural parameters in coassembly is crucial for the fabrication of multicomponent functional materials. Here a proof-of-concept study is presented to reveal the α-substituent effect of aromatic amino acids on their selective coassembly with bipyridine binders. With the assistance of X-ray scattering technique, it is found that individual packing in the solid state as well as bulky effect brought by α-substitution determines the occurrence of coassembly. A well-performed hydrogels based on the complexation between certain aromatic amino acids and bipyridine units are successfully constructed, providing unprecedented smart materials with light irradiation-triggered luminescence. Such hydrogels without the phase separation and photobleaching during light irradiation are able to behave fluorescent imprint materials. This study provides a suitable protocol in rationally designing amino acid residues of short peptides for fabricating self-assembled multicomponent materials. In addition, this protocol is useful in screening potential functional materials on account of diverse self-assembly behavior.

Hydrogen-bonded coassembly of aromatic amino acids with bipyridines is influenced significantly by α-substituted functional groups, exhibiting specific selectivity. Utilizing this protocol, high-quality hydrogels are obtained to show unprecedented light irradiation-induced luminescence. Strong emission from nonemissive hydrogels triggered by light enables the fabrication of fluorescent patterning.

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