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.