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ExoBrite™ CD81 Flow Antibody

Validated antibody for optimal detection of exosome marker CD81 in purified or bead-bound exosomes by flow cytometry.

Product Attributes

Antibody number




Antibody type




Host species



IgG1, kappa

Antibody reactivity (target)



CD81; Target of the antiproliferative antibody 1 (TAPA-1); Tetraspanin-28; Tspan-28

Species reactivity

Baboon, Cynomolgus monkey, Human, Non-human primates

Human gene symbol


Entrez gene ID




Molecular weight

26 kDa

Antibody target cellular localization

Exosomes/EVs, Plasma membrane

Cell/tissue expression

Exosomes, Hepatocytes, Lymphocytes, Monocytes/macrophages

Verified antibody applications

Exosome staining (verified)

Shipping condition

Room temperature

Positive control

MCF-7 cells, MCF-7 derived exosomes

Antibody application notes

Recommended concentration for flow cytometry: 5 uL per 0.1 mL exosomes

Antibody research areas


Antibody/conjugate formulation

PBS, 0.1% BSA, 0.05% azide

Shelf life

Guaranteed for at least 24 months from date of receipt when stored as recommended

Storage Conditions

Store at 2 to 8 °C, Protect fluorescent conjugates from light

Regulatory status

For research use only (RUO)

Catalog #
25 tests
100 tests
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Product Description

ExoBrite™ CD81 Flow Antibody has been validated by Biotium for optimal detection of exosome marker CD81 in purified or bead-bound exosomes by flow cytometry. The antibody conjugates offer exceptional signal-to-noise and include color options for the Pacific Blue™, FITC, and PE channels.

  • Optimal detection of exosome marker CD81 by flow cytometry
  • Validated for purified or bead-bound exosomes
  • Bright signal and low background
  • Available in 3 colors

Extracellular vesicles (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 exosomes are increasingly studied for their potential use in drug delivery and medical diagnostic applications. The most common proteins used as exosome 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 exosomes, but their expression levels vary depending on the cell type of origin.

Exosome antibodies you can trust

Other commercially available antibodies for tetraspanin proteins CD9, CD63, and CD81 are generally not validated for isolated exosomes and may require tedious optimization for your exosome prep and staining protocol. ExoBrite™ Flow Antibody Conjugates were validated to offer bright signal and low background of exosome markers in purified and bead-bound exosomes. ExoBrite™ Isotype Control Flow Antibodies, which have been found to not react with any target in human cells and have the same isotype as the tetraspanin antibodies, are also available as a negative control.

Biotium also offers ExoBrite™ EV Membrane Staining Kits for detection of isolated EVs and exosomes by flow cytometry. ExoBrite™ EV Membrane Staining Kits may also be combined with antibody staining, for multi-parameter analysis.

ExoBrite™ Flow Antibody Conjugates

AntibodyEx/EmDetection ChannelSizeCatalog No.
ExoBrite™ 410/450
CD9 Flow Antibody
416/452 nmPacific Blue ™25 testsP003-410-125
100 testsP003-410-500
ExoBrite™ 490/515
CD9 Flow Antibody
490/516 nmFITC25 testsP003-490-125
100 testsP003-490-500
ExoBrite™ 560/585
CD9 Flow Antibody
562/584 nmPE25 testsP003-560-125
100 testsP003-560-500
ExoBrite™ R-PE
CD9 Flow Antibody
496, 546, 565/578PE25 testsP003-RPE-125
100 testsP003-RPE-500
ExoBrite™ 410/450
CD63 Flow Antibody
416/452 nmPacific Blue ™25 testsP004-410-125
100 testsP004-410-500
ExoBrite™ 490/515
CD63 Flow Antibody
490/516 nmFITC25 testsP004-490-125
100 testsP004-490-500
ExoBrite™ 560/585
CD63 Flow Antibody
562/584 nmPE25 testsP004-560-125
100 testsP004-560-500
ExoBrite™ R-PE
CD63 Flow Antibody
496, 546, 565/578PE25 testsP004-RPE-125
100 testsP004-RPE-500
ExoBrite™ 410/450
CD81 Flow Antibody
416/452 nmPacific Blue ™25 testsP005-410-125
100 testsP005-410-500
ExoBrite™ 490/515
CD81 Flow Antibody
490/516 nmFITC25 testsP005-490-125
100 testsP005-490-500
ExoBrite™ 560/585
CD81 Flow Antibody
562/584 nmPE25 testsP005-560-125
100 testsP005-560-500
ExoBrite™ R-PE
CD81 Flow Antibody
496, 546, 565/578PE25 testsP005-RPE-125
100 testsP005-RPE-500
ExoBrite™ 410/450 IgG1
Isotype Control Flow Antibody
416/452 nmPacific Blue ™25 testsP008-410-125
100 testsP008-410-500
ExoBrite™ 490/515 IgG1
Isotype Control Flow Antibody
490/516 nmFITC25 testsP008-490-125
100 testsP008-490-500
ExoBrite™ 560/585 IgG1
Isotype Control Flow Antibody
562/584 nmPE25 testsP008-560-125
100 testsP008-560-500
ExoBrite™ R-PE IgG1
Isotype Control Flow Antibody
496, 546, 565/578PE25 testsP008-RPE-125
100 testsP008-RPE-500

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