Supramolecular Polymers in Water

Aqueous self-assembly of molecular building blocks into ordered architectures, polymers and materials opens exciting avenues for fundamental developments in nanoscience and applications in biomedical technologies, optoelectronics and catalysis (Chem. Rev. 2016). Taking inspiration from protein functionality in their biological setting, the Besenius lab has produced electrostatic- and redox-regulated supramolecular polymerisations in water (Angew. Chem. 2013, Chem. Eur. J. 2015). The supramolecular monomer designs we have developed are based on β-sheet encoded anionic and cationic peptides that form anisotropic supramolecular copolymers with a nanorod-like morphology. By doing so the materials becomes stimuli-responsive and polymerizations can be turned on and off in response to pH- and redox-triggers. We have shown that the pH-triggered monomer-polymer transition is simply tuned via thermodynamically controlled comonomer affinities (Polym. Chem. 2015), whereas kinetically controlled assemblies are achieved by coupling multiple equilibria through enzyme catalysed processes (Angew. Chem. 2017), or by confining the self-assembly process onto metallic surfaces (Angew. Chem. 2016, Faraday Discuss. 2017).

In order to establish a set of semi-empirical rules for the design of supramolecular nanomaterials we often use the concept of frustrated self-assembly, which describes the balance of positive non-covalent interactions with repulsive forces. Here, we either use electrostatic interactions to tune the repulsive contribution in the frustrated self-assembly (J. Mater. Chem. B 2013Org. Biomol. Chem. 2015), or we rely on steric constraints in order to induce frustration and restrict the one-dimensional self-assembly into well-defined nanorods in water (Chem. Eur. J. 2015). In view of recent reports that anisotropic shapes in the design of biomedical carrier materials outperform conventional isotropic structures, we are particularly interested in the development of supramolecular multifunctional materials and their biomedical applications. For example, we aim to explore applications in immunotherapy (ChemBioChem 2018, 912 & 1142), where we attach a variety of glycopeptide epitopes onto the self-assembling constructs that can activate the immune system for a selective response towards molecular defined specific antigens. Multipotent fully synthetic vaccines, can thus be developed conveniently using a supramolecular engineering approach that rely on the simple mixing of multifunctional monomeric building blocks.

Members involved: Christian Berač, Tim KonradChristian Merfels, Marius ThomasMoritz Urschbach.