More and more attention has been paid to investigate the roles of exosomes in therapeutic and diagnostic applications. Exosome labeling is a novel strategy for monitoring exosomes trafficking in vivo, which contributes to optimizing exosome-based diagnosis and treatment. With years of experiences in exosome labeling, Creative Biolabs has developed advanced biotin labeling platform to detect the distribution and movement of the specific exosomes.

Biotin Labeling

Biotin is a small molecule that can covalently attach to a protein, nucleic acid or other molecule. This process is called biotinylation which is a rapied, specific and is unlikely to disrupts the natural function of proteins and other target molecules. Biotin non-covalently binds to streptavidin and avidin with an extremely high affinity, fast on-rate, and high specificity. And the non-covalent interactions is very strong, even more than the affinity between antibody and antigens and is resistant to extremes of heat, pH and proteolysis. Thus biotin binding to streptavidin (SAV) and avidin is exploited to detect and/or purify proteins. Multiple biotin molecules can be conjugated to a protein of interest, which allows binding of multiple streptavidin, avidin or neutravidin protein molecules and increases the sensitivity of detection of the protein of interest. There is a large number of biotinylation reagents available that exploit the wide range of possible labelling methods.

Application of Biotin Labeling for Exosome

Exosomes are a kind of extracellular vesicles with 30-150 nm diameter and cargo many components of origin cells such as proteins and nucleic acids. Biotin labeling may provide a powerful tool for the investigation of biological features of exosomes. Biotin binding to streptavidin and avidin can label the specific proteins of exosome thereby monitoring the exosome trafficking. A study has quantitatively evaluate the tissue distribution of B16BL6-derived exosomes based on the iodine-125 (¹²⁵I) based on SAV-biotin system. Similarly, antibodies are often conjugated with multiple biotin molecules (3-6 molecules), leading to an amplification step that enhances detection of less abundant antigens. Hence antibody labeled by biotin is also applied for the distribution and visual monitoring of exosomes. While the biotin labeling can improve detection, it can be difficult to use for isolation/purification of proteins or exosomes as the strong interaction between biotin and (strept)avidin can be difficult to disrupt.

Fig.1 Diagram of exosome-bead capture experiments. (Klinker, 2014)

Advantages of Exosome Biotin Labeling in Creative Biolabs

• The highest sensitivity and specificity
• Low effect on exosome features
• A high range of flexibility in exosome biotin labeling
• All-around technical service

Exosome biotin labeling is an effective tool for the investigation of exosomes characteristics and exosomes trafficking for the therapeutic and diagnostic applications. Equipped with state-of-art platforms, scientists in Creative Biolabs are more than happy to help you fully fill the translational properties of exosome. If you are interested in our exosome labeling services, please contact us for more information whenever you feel free.

Reference:

1. Klinker, M. W.; et al. Human B cell-derived lymphoblastoid cell lines constitutively produce fas ligand and secrete MHCII(+)FasL(+) killer exosomes. Front Immunol, 2014, 5:144.

• Exosome Fluorescent Labeling