(a) Assay schematics to maximize magnetic nanoparticle (NMP) binding onto EVs. A two-step bio-orthogonal click chemistry was used to label EVs with MNPs. (b) The microfluidic system for on-chip detection of circulating EVs is designed to detect MNP-targeted vesicles, concentrate MNP-tagged vesicles (while removing unbound MNPs) and provide in-line NMR detection. (c) GBM markers (EGFR, EGFRvIII, PDGFR, PDPN, EphA2 and IDH1 R132H), a positive EV control marker (HSP90), as well as host cell markers (CD41, MHCII) were profiled in both parental cells (left) and their corresponding EVs (right). Using a four-GBM marker combination (EGFR, EGFRvIII, PDPN and IDH1 R132H), GBM derived EVs could be distinguished from host cell–derived EVs. MFI, mean fluorescence intensity; HBMVEC, human brain microvascular endothelial cell; NHA, normal human astrocyte; buffy coat and plasma were isolated from whole blood donated by healthy volunteers. Reprinted with permission from Ref 20. Copyright 2012 Nature Publishing Group.