Seeing the Unseen: Super-Resolution Microscopy in Protein Aggregation Research.

Super-resolution microscopy surpasses the diffraction limit and enables the visualization of biomolecular structures with unprecedented detail. These techniques have been widely used in many scientific areas, including cell biology, genomics, microbiology, and material science. In the field of protein aggregation, a process intimately linked to numerous neurodegenerative diseases, the high spatial resolution of super-resolution microscopy enables the direct observation of the fine structure of different species, ranging from small oligomers to mature aggregates, providing insights into molecular aggregation mechanisms and the pathology of neurodegenerative diseases, such as Parkinson's, Alzheimer's, and Huntington's disease. In this review, we outline the principles of three major super-resolution microscopy techniques, including stimulated emission depletion (STED), structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM), and compare their respective strengths and limitations in studying protein aggregation. We then highlight the recent applications of these techniques in studying protein aggregation, with a focus on aggregate morphology, dynamic formation processes, and interactions with cellular components.