Unraveling the Design Rules in Ultrashort Amyloid-Based Peptide Assemblies toward Shape-Controlled Synthesis of Gold Nanoparticles

The fundamental understanding of the detailed relationship between molecular structure and material function remains a challenging task, until now. In order to understand the relative contribution of aromatic moieties and hydrophobicity of amino acid chains, we designed a library of ultrashort amyloid-like peptides based on Ar-Phe-X (where “Ar” represents different aromatic moieties and “X” represents amino acids having varied side-chain functionalities). Our research clearly indicated that the alteration in the size and hydrophobicity of the aromatic capping play a crucial role compared to the subtle change in the amino acid sequence of the dipeptide in dictating the final self-assembled structure and properties of these short peptide amphiphiles. Further, we explored our detailed understanding toward the controlled synthesis of bioinspired organic–inorganic hybrids. For the first time, we established the differential role of aliphatic and aromatic hydroxyl moieties toward the in situ shape-controlled synthesis of gold nanoparticles in three-dimensional nanostructures of hydrogels. To the best of our knowledge, it is the first report which demonstrated the formation of rectangular platonic gold nanoparticles using simple dipeptide hydrogels, exhibiting pH-dependent size control. Our study shows promising implications in bottom-up nanofabrication of next-generation nanomaterials with emergent properties