Analyzing the miRNA content of extracellular vesicles by fluorescence nanoparticle tracking

A combination of nanoparticle tracking by light scattering (scNTA) and by fluorescence (fNTA) is used to identify the subpopulation of extracellular vesicles (EVs) tracked by fNTA containing at least a threshold number of target miRNA transcripts, which is expressed as a number fraction of the entire population of EVs tracked by scNTA. Detection of the target EV miRNA in fNTA is based on hybridization to miRNA-specific molecular beacons encapsulated in cationic lipoplex nanoparticles that fuse non-specifically with the negatively charged EVs. A stoichiometric analysis of miR-21 in EVs derived from A549 lung cancer cells is presented to demonstrate the method.92