Visual Monitoring of Biomolecular Self-Assembly Dynamics and Imaging of Protein Aggregates by Distinct Emission of a Unique Hydrophobic Carbon Dot

Here, we report a novel and unique application of a special hydrophobic carbon dot (HCD) to monitor biomolecular self-assembly, along with the detection of metastable intermediates and self-aggregates. We exploited the restricted rotation of the S–S bond of the HCD synthesized from dithiosalicylic acid and melamine to illuminate different emission behaviors during the self-assembly of amino acids and proteins. The HCD that exhibits blue emission in amino acid droplets or protein aggregates dynamically changes its emission from blue to red over the time course of the amino acid self-assembly process. This unique and distinct change in emission can be visualized by the naked eye under a UV lamp. The ability of HCD to distinguish the biomolecular self-aggregated structures and monitor the self-assembly dynamics can be utilized for the visual detection of uncontrolled aggregation of proteins and peptides related to neurodegenerative diseases like Alzheimer's disease and Parkinson's disease.