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Updated: Jul 31, 2026
Imaging of Extracellular Vesicles by Atomic Force Microscopy
Published on: September 11, 2019
Sup35NMp morphology evaluation on Au, Si, formvar and mica surfaces using AFM, SEM and TEM
P A Sokolov1, S A Bondarev2, M V Belousov3
1Department of Physics, St. Petersburg State University, Russia.
Abstract:
Prion and some other incurable human neurodegenerative diseases are associated with misfolding of specific proteins, followed by the formation of amyloids. Despite the widespread usage of the transmission electron and of the atomic force microscopy for studing such amyloids, many related methodological issues still have not been studied until now. Here, we consider one of the first amyloids found in Saccharomyces cerevisiae yeast, i.e. Sup35NMp, to study the adsorption of monomeric protein and its fibrils on the surface of mica, silica, gold and on formvar film. Comparison of linear characteristics of these units calculated by processing of images obtained by the atomic force, transmission and scanning electron microscopy was carried out. The minimal number of measurements of fibril diameters to obtain the values in a given confidence interval were determined. We investigated the film formed by monomeric protein on mica surface, which veiled some morphology features of fibrils. Besides, we revealed that parts of the Sup35NMp excluded from the fibril core can form a wide "coat". The length of the protein forming the core of the fibrils was estimated.
Insights
Researchers studied amyloid formation using yeast Sup35NMp protein. They analyzed fibril adsorption on various surfaces and microscopy methods, revealing insights into protein structure and measurement techniques for neurodegenerative disease research.
Area of Science:
- Biochemistry
- Biophysics
- Microscopy
Background:
- Protein misfolding and amyloid formation are hallmarks of incurable neurodegenerative diseases.
- Techniques like electron microscopy are used to study amyloids, but methodological issues persist.
Purpose of the Study:
- To investigate the adsorption of monomeric and fibrillar Sup35NMp protein on different surfaces.
- To compare linear characteristics of amyloid structures using various microscopy techniques.
- To determine optimal measurement parameters for fibril diameter analysis.
Main Methods:
- Atomic Force Microscopy (AFM)
- Transmission Electron Microscopy (TEM)
- Scanning Electron Microscopy (SEM)
- Analysis of Sup35NMp adsorption on mica, silica, gold, and formvar film.
Main Results:
- Established optimal measurement parameters for fibril diameter determination.
- Observed that monomeric protein can form a film obscuring fibril morphology.
- Identified "coats" formed by Sup35NMp parts outside the fibril core and estimated core protein length.
Conclusions:
- Provides a methodological framework for studying amyloid structures using multiple microscopy techniques.
- Offers insights into the structural organization of Sup35NMp fibrils.
- Contributes to understanding amyloid formation relevant to neurodegenerative diseases.
