Amyloid-Inspired Optical Waveguides From Multicomponent Crystalline Microtubes

Crystalline microtubes formed by a spontaneous transition from self-assembled hydrogel fibrils of Fmoc-4-NO2-Phe act as optical waveguides when coassembled with amyloid-binding fluorescent molecules. Specifically, thioflavin-T (ThT), which exhibits amyloid-specific fluorescence, coassembles with Fmoc-4-NO2-Phe and is selectively confined to the interior of the resulting microtubes. These two-component materials exhibit optical waveguide light transmission via internal reflectance in the interior cavity of the tube upon excitation of the ThT fluorophore. In addition, microtube assembly in the presence of both ThT and a fluorescence energy transfer (FRET) partner, propidium iodide (PI), results in three-component crystalline microtubes that propagate incident energy via excitation of ThT and FRET excitation of PI. These optical waveguides are an example of amyloid-inspired, multicomponent materials with the potential for use in light-harvesting and energy-transfer applications.