Characterisation of exosomes derived from human cells by nanoparticle tracking analysis and scanning electron microscopy

► Exosomes from three different cell lines had a diameter of 110 nm. ► Ultracentrifugation does not change size or shape of exosomes. ► Multiple shock-freezing and thawing does not affect the exosomes. ► Storage at 4 °C and 37 °C in dispersion leads to slow degradation of exosomes. ► Nanoparticle tracking analysis is well suited to study exosomes.