“…Our team has pioneered the SIMS approach whereby a surface is stochastically bombarded with a suite of individual nanoprojectiles (e.g., ∼ 1 keV/atom Au 400 4+ ) in the event-by-event bombardment detection mode. − A bombardment event generates a crater of ∼10 nm in diameter within an organic layer on the surface; ionized ejecta from each bombardment event are detected, and mass spectra from millions of such events are compiled. This approach has been used by us previously to examine the heterogeneity of biointerfaces, , thin films, , nanoparticles, − and integrated circuits. We have recently demonstrated the feasibility of NP-SIMS for EV analysis using antibodies (Abs)-labeled with halide MS tags and targeting abundant and ubiquitous surface markers, CD63 and CD81 …”