Design and properties of functional nanotubes from the self-assembly of cyclic peptide templates

β-Sheet forming self assembling cyclic peptides offer a versatile scaffold for the construction and control of hydrogen-bonded nanotube assemblies. These structures have major advantages over other nanoscale tubular structures, including sub-nanometer control over the internal diameter, and the ability to control internal and external chemical functionality. This Tutorial Review presents an overview of nanotubes derived from this class of cyclic peptides. The design rationale for functional nanotubes based on cyclic peptide ring size and chemical functionality is discussed. Additionally, we highlight the recent expansion of the nanotube toolbox through conjugation of (macro)molecules to the cyclic peptides. These provide additional functionality and control nanotube dimensions that could potentially prove beneficial in future applications.