Abstract
Analytical characterization of small biological particles, such as extracellular vesicles (EVs), is complicated by their extreme heterogeneity in size, lipid, membrane protein, and cargo composition. Analysis of individual particles is essential for illuminating particle property distributions that are obscured by ensemble measurements. To enable high-throughput analysis of individual particles, liftoff nanocontact printing (LNCP) is used to define hexagonal antibody and toxin arrays that have a 425 nm dot size, on average, and 700 nm periodicity. The LNCP process is rapid, simple, and does not require access to specialized nanofabrication tools. These densely packed, highly ordered arrays are used to capture liposomes and bacterial outer membrane vesicles on the basis of their surface biomarkers, with a maximum of one particle per array dot, resulting in densely packed arrays of particles. Despite the high particle density, the underlying antibody or toxin array ensured that neighboring individual particles are optically resolvable. Provided target particle biomarkers and suitable capture molecules are identified, this approach can be used to generate high density arrays of a wide variety of small biological particles, including other types of EVs like exosomes.