ExoBrite™ Annexin EV Staining Kits

ExoBrite™ Annexin EV Staining Kits were designed to overcome some of the challenges of EV detection, particularly in flow cytometry. ExoBrite™ Annexin EV Stains bind to molecules in the EV membrane for bright, specific staining, with little to no background.

ExoBrite™ Annexin EV Stains are uniquely formulated conjugates of Annexin V, a 35-36 kDA calcium-dependent phospholipid-binding protein with high affinity for phosphatidyleserine (PS). Annexin V conjugates have been used to detect EVs due to the presence of PS on most EV membranes.

ExoBrite™ Annexin EV Stains were designed to overcome some of the challenges of EV detection, particularly in flow cytometry. For example, lipophilic membrane dyes commonly used to stain EVs can form aggregates of a similar size as exosomes or EVs, thus confounding analysis. Conversely, ExoBrite™ Annexin EV Stains are specially formulated to minimize aggregation in flow cytometry, allowing EVs to be identified with bright staining with minimal background. In addition, ExoBrite™ Annexin EV Stains were designed to offer broad coverage of EVs isolated from different sources. We tested EVs derived from 9 cell lines and ExoBrite™ Annexin EV Stains showed strong staining for all of them.

EVs are often labeled with fluorescent antibodies targeting one or more of the tetraspanin proteins CD9, CD63, and CD81. ExoBrite™ Annexin staining can be combined with antibody staining, for multi-parameter analysis.

Notes:

1. ExoBrite™ Annexin EV Stains have been found to label EVs derived from all cell lines tested (see Validated EV Sources below), but may not stain EVs from every source.
2. In our testing, we have found that ExoBrite™ 490/515 dye may bind to streptavidin coated surfaces or beads if free biotin binding sites are not blocked. We recommend performing a biotin blocking step after binding your biotinylated capture antibody to streptavidin beads or surfaces when using ExoBrite™ 490/515 conjugates. Alternatively, consider using a different ExoBrite™ dye for staining EVs captured on streptavidin beads or surfaces.

ExoBrite™ Annexin EV Staining Kits

Validated EV Sources for ExoBrite™ EV Surface Stains

Biotium also offers other validated ExoBrite™ reagents for flow cytometry, western blotting, or super-resolution imaging.

Learn about Biotium’s new ExoBrite™ True EV Membrane Stains. These genuine lipophilic membrane dyes are designed for superior pan-EV labeling over other membrane dyes including PKH, DiO, DiI, and DiD. Biotium also offers ExoBrite™ CTB EV Stains (cholera toxin B conjugates) and ExoBrite™ WGA EV Stains (wheat germ agglutinin) optimized for bright and sensitive staining of EVs. The ExoBrite™ EV Surface Stain Sampler Kit contains each of Biotium’s ExoBrite™ EV Surface Stains (CTB, WGA, and Annexin V) for assessing which stain offers the best coverage for the EV samples of interest. Biotium also offers ExoBrite™ Antibody Conjugates for optimal detection of CD9, CD63, and CD81 EV markers by flow cytometry and western blotting. For super-resolution imaging by STORM, learn about our ExoBrite™ STORM CTB EV Staining Kits available in four CF® Dyes validated for STORM.

Note: We do not recommend using ExoBrite™ 410/450 Annexin EV Stain or ExoBrite™ 490/515 Annexin EV Stain to stain bead-bound EVs. For bead-bound EVs we recommend using ExoBrite™ 560/585 Annexin EV Stain, ExoBrite™ 650/665 Annexin EV Stain, as well as ExoBrite™ CTB EV Stains.