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.

The coiled coil is a superhelical protein structural motif that consists of two or more α-helical peptides that are wrapped around each other in superhelical fashion. Coiled coils are amongst the most ubiquitous folding motifs found in proteins and have not only been identified in structural proteins but also play an important role in various intracellular regulation processes as well as membrane fusion. The aim of this critical review is to highlight the potential of coiled coil peptide sequences for the development of self-assembled, responsive and/or bioactive materials. After a short historical overview outlining the discovery of this protein folding motif, the article will briefly discuss naturally occurring coiled coils. After that, the basic rules, which have been established to date for the design of coiled coils will be briefly summarized followed by a presentation of several classes of coiled coils, which may represent interesting candidates for the development of novel self-assembled, responsive and/or bioactive materials. This critical review will end with a section that summarizes the different coiled coil based (hybrid) materials that have been reported to date and which hopefully will help to stimulate further work to explore the full potential of this unique class of protein folding motifs for the development of novel self-assembled, responsive and/or bioactive materials (212 references).

The synthesis of multiblock copolymers is often considered to be synthetically challenging and time consuming. In this contribution, the development of a remarkably efficient and versatile procedure to access multiblock copolymers via reversible addition–fragmentation chain transfer (RAFT) polymerization is reported. The robustness and versatility of the RAFT process are demonstrated in this report by preparing multiblock copolymers using uncommon experimental conditions. The synthesis of each block was performed in the presence of air and only required 3 minutes to reach near full monomer conversion. This approach removes the necessity to deoxygenate the solution and allows access to complex copolymer structures in very short time periods. For example, this process allowed the preparation of a heptablock homopolymer with a well-defined architecture in just 21 minutes. We also discuss the limitations inherent to this approach. This strategy is shown to be particularly efficient when blocks with low degrees of polymerization (DP < 20) are targeted. For blocks with higher DPs (DP > 50), the procedure is typically limited to the preparation of di- or triblock copolymers.

Self-assembled nanotubular structures have numerous potential applications but these are limited by a lack of control over size and functionality. Controlling these features at the molecular level may allow realization of the potential of such structures. Here we report a new generation of self-assembled cyclic peptide–polymer nanotubes with dual functionality in the form of either a Janus or mixed polymeric corona. A ‘relay’ synthetic strategy is used to prepare nanotubes with a demixing or mixing polymeric corona. Nanotube structure is assessed in solution using ¹H–¹H nuclear Overhauser effect spectroscopy NMR, and in bulk using differential scanning calorimetry. The Janus nanotubes form artificial pores in model phospholipid bilayers. These molecules provide a viable pathway for the development of intriguing nanotubular structures with dual functionality via a demixing or a mixing polymeric corona and may provide new avenues for the creation of synthetic transmembrane protein channel mimics.