Cellular microvesicles and nanovesicles (exosomes) are involved in many disease processes and have major potential as biomarkers. Ho
wever, developments in this area are constrained by limitations in the technolo
gy available for their measurement. Here
we report on the use of fluorescence nanoparticle trackin
g analysis (NTA) to rapidly size and phenotype cellular vesicles. In this system vesicles are visualized by li
ght scatterin
g usin
g a li
ght microscope. A video is taken, and the NTA soft
ware tracks the bro
wnian motion of individual vesicles and calculates their size and total concentration. Usin
g human placental vesicles and plasma,
we have demonstrated that NTA can measure cellular vesicles as small as ?0 nm and is far more sensitive than conventional flo
w cytometry (lo
wer limit ?00 nm). By combinin
g NTA
with fluorescence measurement
we have demonstrated that vesicles can be labeled
with specific antibody-conju
gated quantum dots, allo
win
g their phenotype to be determined.
From the Clinical Editor
The authors of this study utilized fluorescence nanoparticle tracking analysis (NTA) to rapidly size and phenotype cellular vesicles, demonstrating that NTA is far more sensitive than conventional flow cytometry.