Solvothermally Mediated Self-Assembly of Ultralong Peptide Nanobelts Capable of Optical Waveguiding.

The formation of ultralong peptide crystalline nanobelts using a solvothermal approach from a di-phenylalanine gel within 10 min, where the self-assembly process is accelerated by several orders of magnitude compared with the month-long glutaraldehyde induction method previously reported, has been demonstrated. The solvothermal treatment can facilitate the phase separation of di-phenylalanine gels while speeding up the kinetics of the intramolecular cyclization reaction and concomitant crystallization. Moreover, the modulation effect of formaldehyde as an additive is revealed, and that a small amount of formaldehyde leads to thicker crystalline platelets capable of curved optical waveguiding that can potentially be applied in advanced bio-optical and optoelectronic devices, a rare feat with peptide-based crystals.