Spatial and temporal control in multistimuli-responsive structures are key properties to advance and optimize functional soft matter. In an attempt to develop autonomous non-equilibrium states in supramolecular polymers, and hydrogel materials, we have expanded the above concept of ß–sheet self-assembly of alternating hydrophilic and hydrophobic amino acids. An interplay of pH- and oxidation-stimuli, promoted by the production of reactive oxygen species (ROS) thus lead to transient supramolecular polymerisations, with tuneable lifetimes and stabilities (Angew. Chem. 2017). In addition, the monomers can be equipped with thermoresponsive triethylene glycol chains, which in the polymeric state lead to a thermogelation process at a biomedically relevant temperature of 30-35 °C. Since reactive oxygen species play an important role in signal transduction cascades, our materials offer great potential for applications of these dynamic biomaterials in redox microenvironments.
We further aim to study the fundamentals of the supramolecular polymerisation mechanism, the thermodynamics which dictate the size and stability of the colloidally stable polymers, as well as kinetic parameters and non-equilibrium states (Macromolecules 2017). Most recently we were able to extend the design rules from small molecular weight building blocks to macromolecular designs that upon folding produce viromimetic particles, with a densely ordered peptide core, that is surrounded by a shielding and protein repelling core of hydrophilic polymer (Chem. Commun. 2018). A reduction of the pH leads to disassembly, and the pH stability window for the particles follow the same behaviour as protein-based assemblies, like virus particles.