Developing sequence design rules for peptoids capable of assembly into nano-sandwiches

Peptoids are a peptidomimetic that differ in structure from peptides based on their placement of the side chain on the nitrogen as opposed to the alpha carbon while still retaining all other qualities of a peptide backbone. Peptoids can be used to create gold nanoparticle nanosheets that have potential applications as pollutant sensors. The formation of these nanosheets relies on the specific chemical structures of the peptoid sequence and the gold nanoparticle ligand. Here, the peptoids are functionalized with alternating hydrophobic and hydrophilic side groups, creating amphiphilic molecules that can self-assemble at fluid interfaces from an aqueous solution. Due to the strong interactions between sulfur and gold, the gold nanoparticles can be functionalized with thiol ligands to make hydrophobic nanoparticles, which are dispersible in hydrophobic solvents. To make the gold nanosheets, an oil-water interface is created from gold nanoparticle and peptoid solutions. Upon collapse of the interface, gold nanosheets form where gold particles are sandwiched between layers of peptoid, where the peptoids successfully interact with their aqueous environment and their hydrophobic core due to their amphiphilic properties. The focus of this project is on optimizing the solid phase synthesis of peptoids with different hydrophobic residues to better understand what specific sequence features are required for gold nanosheet formation. However, the standardized methods for peptoid synthesis are quite time consuming. Literature suggests that the use of heat can fraction the time per reaction, and doing so will create more ideal methods in our lab. Additionally, it is expected that the use of heat to increase the rate of the reaction will give the same results as prior. Overall, this work can result in the discovery of a span of peptoid sequences that can be used to form this interesting new class of two-dimensional nanomaterials.