The Intrinsic Fluorescence of Peptide Self‐Assemblies Across pH Levels

Abstract The regulation of solution pH on the structural and optical properties of peptide self‐assemblies remains a critical yet unresolved issue in peptide research. This study investigates the heptapeptide Ac‐IHIHIQI‐NH 2 and its intrinsic fluorescence across a range of pH levels, demonstrating that variations in pH lead to significant changes in the morphology of the self‐assembled structures. While the position of the fluorescence emission remains constant—due to the stability provided by the hydrogen bonding network of the peptide backbone—the intensity of the fluorescence exhibits a direct correlation with the degree of self‐assembly. This finding underscores a dynamic relationship between structural morphology and optical properties. Notably, the ability of the peptide to self‐assemble under diverse pH conditions is a novel observation that contrasts with previously reported literature. By employing a computationally driven approach, complemented by rigorous experimental validation, this work establishes a new paradigm for studying complex interacting systems such as peptide self‐assembly. Our findings enhance the understanding of how environmental factors influence peptide behavior and pave the way for the design of innovative peptide‐based materials with tunable optical characteristics, with potential applications in bioluminescent probes and diagnostic tools for neurodegenerative diseases.