Synthesis of One-Dimensional Non-Covalently-Bonded Macromolecules by Self-Assembly of Peptide Bolaamphiphiles

Abstract

In nanotechnology, one-dimensional nanostructures are one of the important targets to construct nanodevices. In nature, functional biological molecules such as peptides, sugars, nucleic acids, and lipids grow up to macromolecular biological structures by non-covalent bonds such as hydrogen bond, hydrophobic interaction, electrostatic interaction, and so on. Peptides can form interesting secondary structures represented by α-helix and β-sheet using amide-amide hydrogen-bond networks. Some peptide lipids were known to form 1-D nanomaterials with solid surface such as nanotubes and nanofibers due to hydrogen-bond networks between the peptides. We provided here the formation of 1-D non-covalently-bonded macromolecules from peptide bolaamphiphiles. Bolaamphiphiles have an advantage of more stable nanostructures formation in comparison with usual amphiphiles. Oligoglycine bolaamphiphiles self-assembled in water to form lipid microtubes or nanotubes via polyglycine II-type 2-D hydrogen-bond networks. In contrast, valylvaline bolaamphiphiles produced nanofibers due to β-sheet-type 1-D hydrogen-bond networks. COOH groups on the surface of the nanofibers can also provide a scaffold for 1-D organization of transition-metal cations. The reduction of these metal cations on the surface of the nanofibers gave 1-D organized copper nanoparticles