An audible sound approach to peptide systems chemistry

• Applicant: Dr. Charalampos Pappas
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation ; Biomaterials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 495280186

Living systems possess overwhelming molecular complexity that largely results from combinations of just twenty amino acids. Inspired by such dynamics where molecular assemblies perform tasks that exceed the functionality of their basic constituents, systems chemistry focusses on connectedness, interactivity and patterns. Despite progress in the direction of peptide chemical networks, the manifestation and control of dynamics in these systems, by introducing new chemical and physical tools remains a grand challenge. Further, the emission of chemical messengers, or physical counter-stimuli, which in turn can trigger a secondary response, such as assembly, catalysis and movement remains largely answered. The overall aim of this project is to develop peptide self-assembling systems capable of responding to audible sound waves. In order to achieve this ambitious aim, we will first trigger the formation of supramolecular structures and hydrogels of short peptide amphiphiles using audible sound and manual shaking. We will investigate the way in which counter-stimuli, such as temperature, impacts the properties of such systems and offer reversibility in the structures formed. Aromatic peptide amphiphiles capable of assembling into different supramolecular nanostructures will be exposed to various frequencies (100 - 5000 Hz) and we will examine whether low-energy pressure waves can be used to alter their properties. Following this understanding, we will target the formation of hydrogels and coacervates, exhibiting distinct chemical domains. We will utilize the strategy of audible sound-induced dissolution and transportation of atmospheric gases (CO2), and establish the formation of pH-responsive chemical systems, leading to the construction of predictable and reproducible spatiotemporal assemblies, including peptide nanofibers and mixed systems composed of gels and droplet coacervates. The final aim is to investigate possibilities for directing the formation of non-equilibrium assemblies based on single amino acids, while expanding towards more dynamic peptide chemical networks, utilizing simple carbamylation reactions on cysteine residues. In these systems, audible sound will be utilized to produce peptide hydrogels and chemical networks (oligomers based on disulphides) with different chemical domains, featuring regular spatiotemporal patterns resulting from oxygen-rich and oxygen-poor regions. The project will reveal how liquid vibrations and pressure waves affect the formation of peptide-base supramolecular assemblies, and will provide new insights into the fields of peptide systems chemistry, non-equilibrium assemblies and acoustic materials.

• DFG Programme: Research Grants