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Validated antibody for optimal detection of EV marker CD81 in extracellular vesicle (EV) extracts by fluorescent western blot or chemiluminescence.
ExoBrite™ CD81 Western Antibody is validated by Biotium for optimal detection of extracellular vesicle (EV) marker CD81 in EV extracts by fluorescent western blot. It is available conjugated to ExoBrite™ 680/700 or ExoBrite™ 770/800 near-infrared fluorescent dyes, which offer greater signal-to-noise than visible light fluorescent dyes for western blotting, as well as in an HRP-conjugated format for chemiluminescent detection.
EVs, including exosomes, are lipid-bound vesicles that are released from cells. EVs display specific surface proteins and can carry nucleic acids and other cargo, allowing them to transfer biological information between cells in different parts of the body. Therefore EVs are increasingly studied for their potential use in drug delivery and medical diagnostic applications. The most common proteins used as EV markers are CD9, CD63, and CD81, members of the tetraspanin family. Tetraspanins are plasma membrane proteins with many proposed functions, including activation and sorting of other membrane proteins. They are also thought to play a role in the targeting of proteins to multivesicular bodies (MVBs) and exosomes. These tetraspanins are broadly expressed on many cell types and can therefore be detected on many types of EVs, but their expression levels vary depending on the cell type of origin.
EV antibodies you can trust
Other commercially available antibodies for tetraspanin proteins CD9, CD63, and CD81 are generally not validated for isolated EVs and may require tedious optimization for your EV prep and staining protocol. ExoBrite™ Western Antibody Conjugates were validated to offer bright signal and low background of EV markers in EV extracts. ExoBrite™ Calnexin Western Antibody detects a protein of the endoplasmic reticulum that is not found in EVs. It is offered as a negative control to assess the purity of isolated EV extracts.
If you are using secondary antibodies for western detection, Biotium also offers unconjugated recombinant antibodies against CD9, CD63, and CD81. ExoBrite™ Flow Antibody Conjugates are also available for optimal detection of CD9, CD63, and CD81 EV markers by flow cytometry.
For general EV staining, Biotium offers ExoBrite™ stains conjugated to cholera toxin B (CTB), wheat germ agglutinin (WGA), and Annexin V. These stains are specially formulated for bright and specific detection of isolated EVs by flow cytometry. These ExoBrite™ stains may also be combined with antibody staining, for multi-parameter analysis.
Biotium also provides ExoBrite™ STORM Antibodies against CD9, CD63, and CD81, as well as ExoBrite™ STORM CTB EV Stains that use CF® Dyes engineered specifically for high-performance super-resolution imaging by STORM.
| Antibody | Ex/Em | Conc. | Size | Catalog No. |
|---|---|---|---|---|
| ExoBrite™ 680/700 CD9 Western Antibody | 681/698 nm | 100 ug/mL | 25 tests | P003-680-250 |
| 100 tests | P003-680-1000 | |||
| ExoBrite™ 770/800 CD9 Western Antibody | 770/797 nm | 100 ug/mL | 25 tests | P003-770-250 |
| 100 tests | P003-770-1000 | |||
| ExoBrite™ HRP CD9 Western Antibody | N/A | 100 ug/mL | 50 tests | P003-HRP-500UL |
| ExoBrite™ 680/700 CD63 Western Antibody | 681/698 nm | 100 ug/mL | 25 tests | P004-680-250 |
| 100 tests | P004-680-1000 | |||
| ExoBrite™ 770/800 CD63 Western Antibody | 770/797 nm | 100 ug/mL | 25 tests | P004-770-250 |
| 100 tests | P004-770-1000 | |||
| ExoBrite™ HRP CD63 Western Antibody | N/A | 100 ug/mL | 50 tests | P004-HRP-500UL |
| ExoBrite™ 680/700 CD81 Western Antibody | 681/698 nm | 100 ug/mL | 25 tests | P006-680-250 |
| 100 tests | P006-680-1000 | |||
| ExoBrite™ 770/800 CD81 Western Antibody | 770/797 nm | 100 ug/mL | 25 tests | P006-770-250 |
| 100 tests | P006-770-1000 | |||
| ExoBrite™ HRP CD81 Western Antibody | N/A | 100 ug/mL | 50 tests | P006-HRP-500UL |
| ExoBrite™ 770/800 Calnexin Western Antibody | 770/797 nm | 100 ug/mL | 25 tests | P007-770-250 |
| 100 tests | P007-770-1000 |
While early studies of EVs attempted to use first-generation membrane dyes like DiI or PKH to stain EVs, more recently this class of dyes has been found to be largely unsuitable for EV staining due to their high degree of aggregation. Dye aggregation not only generates nonspecific particles that are indistinguishable from EVs in flow cytometry, but also results in poor EV labeling efficiency. Biotium developed the ExoBrite™ True EV Membrane Stains in response to our customers difficulties with using traditional membrane dyes to stain EVs. See our Literature Digest for more information.
We strongly recommend our ExoBrite™ Flow Antibody Conjugates for staining both purified or bead-bound EVs. The antibodies are validated and optimized to offer bright signal and low background. They are available against human or mouse CD9, CD63, and CD81 tetraspanin proteins.
Yes, EVs can be stained simultaneously with an ExoBrite™ True EV Membrane Stain and a fluorescent antibody.
With purified EVs, we have seen good results when EVs were stained in 500 mL of 1X ExoBrite™ plus 1 ug/mL fluorescent antibody. Please view our Product Information Sheet for detailed protocols.