Open AccessSize and concentration analyses of extracellular vesicles by nanoparticle tracking analysis: a variation study
Author(s) -
Vestad Beate,
Llorente Alicia,
Neurauter Axl,
Phuyal Santosh,
Kierulf Bente,
Kierulf Peter,
Skotland Tore,
Sandvig Kirsten,
Haug Kari Bente F.,
Øvstebø Reidun
Publication year - 2017
Publication title -
journal of extracellular vesicles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.94
H-Index - 68
ISSN - 2001-3078
DOI - 10.1080/20013078.2017.1344087
Subject(s) - extracellular vesicles , nanoparticle tracking analysis , coefficient of variation , comparability , software , tracking (education) , microvesicles , computer science , biological system , biomedical engineering , chemistry , chromatography , mathematics , biology , medicine , biochemistry , psychology , microrna , pedagogy , combinatorics , gene , programming language , microbiology and biotechnology
Current methods for characterisation of extracellular vesicles (EVs) need further standardisation in order to obtain an acceptable level of data comparability. Size and concentration of EVs can be determined by nanoparticle tracking analysis (NTA). However, both the heterogeneity of EVs and the choice of instrument settings may cause an appreciable analytical variation. Intra‐assay (within‐day, n = 6) and inter‐assay (day‐to‐day, n = 6) variations (coefficient of variation, % CV) of different preparations of EVs and artificial vesicles or beads were determined using two NanoSight NS500 instruments, located at different laboratories. All analyses were performed by the same operator. The effect of applying identical software settings or instrument‐optimised settings for each sample type and instrument was also evaluated. Finally, the impact of different operators and the use of two different software versions were investigated. The intra‐assay CVs were 1–12% for both EVs and artificial samples, measured on the same instrument. The overall day‐to‐day variation was similar for both instruments, ranging from 2% to 25%. However, significantly different results were observed between the two instruments using identical software settings. The effect of applying instrument‐optimised settings reduced the mismatch between the instruments, resulting in little to no significant divergences. The impact of using different operators and software versions when analysing silica microspheres and microvesicles from monocytes using instrument‐optimised settings on the same instrument did not contribute to significant variation compared to the overall day‐to‐day variation of one operator. Performance differences between two similar NTA instruments may display significant divergences in size and concentration measurements when analysing EVs, depending on applied instrument settings and technical conditions. The importance of developing a streamlined and standardised execution of analysis, as well as monitoring longitudinal variation parameters on both biological and synthetic samples, should be highlighted.