Summary

Multidomain peptide materials combine the structural precision of natural oligopeptide sequences with the scalability of synthetic polymers. They serve as modular building blocks for supramolecular polymerization in water, in order to prepare synthetic mimics of extracellular matrices, cytoskeletal mimics or silk-like biomaterials. Here, our aim is to develop segmented oligopeptide motifs that allow control over the ratio of intra- to inter-particle folding and therefore the branching (the defect) in 1D supramolecular polymers. These act as cross-linking sites for 1D assemblies and induce the formation of viscoelastic hydrogels (Fig. 1). This strategy provides control over multiple length and timescales. Using charged β-sheet peptide domains, which are connected via flexible and disordered hydrophilic polymer segments, ABA’-type peptide-polymer-peptide conjugates (PPCs) are synthesized. These building blocks assemble into defect free supramolecular polymers (Fig. 1, left). Introduction of charge complementary peptide-conjugates, which do not self-fold but instead selectively co-assemble with the host supramolecular co-polymer, act as defects und branching units (Fig. 1, right). In consequence, the rational design of the peptide subunits, hydrophilic polymer length allows to modulate the kinetics of supramolecular polymerization, uptake of the defect sites and ultimately tune the assembly protocol for the multicomponent hierarchal structures. Compared to covalent hydrogels, dynamic supramolecular networks remain poorly understood. The application of multicomponent supramolecular polymers enables the design of molecular defects and investigate their role in network formation. The impact on the rheological properties will be evaluated to target tunable mechanical properties. Using a defect engineering methodology, we aim to further develop mechanochromic hydrogels using inter-strand folding defects which are extended with mechanosensitive organic moieties. These will allow for visualization of complex cell-matrix interactions or mechanical damage in composite hydrogel materials.