Controlled fiberization of dipeptide in merging phases leads to collagen-level strength and opto/electric mechanofunctionalities.

Artificial synthesis and manipulation of functional amyloid-like fibrils with both positive and negative biological roles in living organisms are still major challenges. As a kind of typical building sequences, diphenylalanine and its derivatives have attracted substantial interests due to their outstanding self-assembly ability and unique combinations of biological, physical, and chemical properties. Herein, inspired by the thermodynamic behavior of cellular fiberization, we describe a novel approach which utilizes a phase merging process in the water/hexafluoroisopropanol binary solutions to initiate and modulate self-assembly of diphenylalanine monomers. This approach leads to the formation of ultralong aligned fiber bundles with an aspect ratio approaching 1000. The elastic modulus is 2-6 GPa as shown by electrically controlled bending and the tensile strength is up to 90 MPa measured by controlled lifting. Light-triggered bending is realized after incorporation with azobenzene molecules and the physiological robustness at different pH, temperature, and humidity is verified. The formation mechanism allows control of incorporative self-assembly of short peptides and paves the way for manipulation of other solution-based self-assembly processes.