Does ultracentrifugation processing duration correlate with successful isolation of exosomes?
Current literature shows no consensus on the theory that longer centrifugation time helps isolate more exosomes without a decrease in quality.1 Some researchers maintain that, to reduce contamination of the final pellet with excessive protein, centrifugation beyond 4 hours should be avoided.3 Others report success with a density gradient protocol that requires 16+ hours of centrifugation,4 while others assert that certain vesicles must be centrifuged from 62-90 hours to reach equilibrium density.5,6 Optimum centrifugation time may very well depend on the cell line being studied.2 For now, more research on this topic is needed.
 Lobb RJ, Becker M, Wen SW, et al. Optimized exosome isolation protocol for cell culture supernatant and human plasma. J Extracell Vesicles. 4; 27031: (2015). doi: org/10.3402/jev.v4.27031.
 Jeppesen DK, Hvam, M, et al. Comparative analysis of discrete exosome fractions obtained by differential centrifugation. J Extracell Vesicles. 3; 25011: (2014). doi: org/10.3402/jev.v3.25011.
 Cvjetkovic A, Lötvall J, Lässer C. The influence of rotor type and centrifugation time on the yield and purity of extracellular vesicles. J Extracell Vesicles. 3; 23111: (2014). doi: org/10.3402/jev.v3.23111.
 Taylor DD and Shah S. Methods of isolating extracellular vesicles impact down-stream analyses of their cargoes. Methods. 87; 3–10: (2015). doi: org/10.1016/j.ymeth.2015.02.019.
 Palma J, Yaddanapudi SC, Pigati L, et al. MicroRNAs are exported from malignant cells in customized particles. Nucleic Acids Res. 40; 9125–9138: (2012). doi: 10.1093/nar/gks656.
 Aalberts M, van Dissel-Emiliani FM, van Adrichem NP, et al. Identification of Distinct Populations of Prostasomes That Differentially Express Prostate Stem Cell Antigen, Annexin A1, and GLIPR2 in Humans. Biol Reprod. 86; 82: (2012). doi: 10.1095/biolreprod.111.095760.