Comparison and optimization of nanoscale extracellular vesicle imaging by scanning electron microscopy for accurate size-based profiling and morphological analysisShow others and affiliations
2021 (English)In: Nanoscale Advances, E-ISSN 2516-0230, Vol. 3, no 11, p. 3053-3063Article in journal (Refereed) Published
Abstract [en]
Nanosized extracellular vesicles (EVs) have been found to play a key role in intercellular communication, offering opportunities for both disease diagnostics and therapeutics. However, lying below the diffraction limit and also being highly heterogeneous in their size, morphology and abundance, these vesicles pose significant challenges for physical characterization. Here, we present a direct visual approach for their accurate morphological and size-based profiling by using scanning electron microscopy (SEM). To achieve that, we methodically examined various process steps and developed a protocol to improve the throughput, conformity and image quality while preserving the shape of EVs. The study was performed with small EVs (sEVs) isolated from a non-small-cell lung cancer (NSCLC) cell line as well as from human serum, and the results were compared with those obtained from nanoparticle tracking analysis (NTA). While the comparison of the sEV size distributions showed good agreement between the two methods for large sEVs (diameter > 70 nm), the microscopy based approach showed a better capacity for analyses of smaller vesicles, with higher sEV counts compared to NTA. In addition, we demonstrated the possibility of identifying non-EV particles based on size and morphological features. The study also showed process steps that can generate artifacts bearing resemblance with sEVs. The results therefore present a simple way to use a widely available microscopy tool for accurate and high throughput physical characterization of EVs.
Place, publisher, year, edition, pages
Royal Society of Chemistry , 2021. Vol. 3, no 11, p. 3053-3063
Keywords [en]
Cell culture, Diagnosis, Diffraction, Image enhancement, Scanning electron microscopy, Diffraction limits, Disease diagnostics, Intercellular communications, Morphological analysis, Morphological features, Nanoparticle tracking analysis, Non small cell lung cancer, Physical characterization, Particle size analysis
National Category
Cell Biology
Identifiers
URN: urn:nbn:se:ri:diva-54518DOI: 10.1039/d0na00948bScopus ID: 2-s2.0-85107416242OAI: oai:DiVA.org:ri-54518DiVA, id: diva2:1570935
Note
Funding details: 52614, 75032; Funding details: 2016-05051; Funding details: Cancerfonden, CAN 2015/401, CAN 2018/597; Funding details: Karolinska Institutet, KI; Funding details: Stockholms Läns Landsting, 20180404; Funding details: Uppsala Universitet; Funding details: Cancerföreningen i Stockholm, 171123, 191293, 201202; Funding text 1: The supporting grants for this study were from the Erling Persson Family Foundation (to AD, JL, RL, KV and KF), Veten-skapsrådet (grant no. 2016-05051), the Stockholm Cancer Society (#171123, ##201202 (RL) and #191293 (KV)), the Swedish Cancer Society (CAN 2015/401 and CAN 2018/597 to RL), the Stockholm County Council (#20180404 to RL) and Karolinska FOUU funding (#75032 and #52614 (RL and KV)).; Funding text 2: We would like to thank Federico Pevere from Uppsala University (UU) for his help in sample sputtering and SEM imaging, and Victoria Sternhagen from UU for her suggestions and help in high resolution SEM imaging, as well as MSc. Vasiliki Arapi, previously at Karolinska Institutet, for her excellent help with western blot analyses.
2021-06-222021-06-222022-02-10Bibliographically approved