Extracellular vesicles (EVs), including exosomes, are nanoscale membrane particles shed from cells and contain cellular proteins whose makeup could inform cancer diagnosis and treatment. Most analyses have focused on surface proteins while analysis of intravesicular proteins has been more challenging. Researchers from Massachusetts General Hospital report an EV screening assay for both intravesicular and transmembrane proteins using a nanoplasmonic sensor. Termed iNPS (intravesicular nanoplasmonic system), this platform used nanohole-based surface plasmon resonance (SPR) for molecular detection. Specifically, we i) established a unified assay protocol to detect intravesicular as well as transmembrane proteins; and ii) engineered plasmonic substrates to enhance detection sensitivity. The resulting iNPS enabled sensitive (0.5 μL sample per marker) and high-throughput (a 10 × 10 array) detection for EV proteins. When applied to monitor EVs from drug-treated cancer cells, the iNPS assay revealed drug-dependent unique EV protein signatures. The researchers envision that iNPS could be a powerful tool for comprehensive molecular screening of EVs.
Analyses of intravesicular exosomal proteins using a nano-plasmonic system
Park J, Im H, Hong S, Castro CM, Weissleder R, Lee H. (2018) Analyses of Intravesicular Exosomal Proteins Using a Nano-Plasmonic System. ACS Photonics 5(2):487-494. [abstract]