Exosome Quantitation
A Range of Fast and Sensitive Options for Exosome Quantitation:When you need to know the amount of exosomes you’ve isolated, our partner SBI offers a range of options that meet most quantitation needs.
For highly sensitive (<1 ug protein equivalent) and fast quantitation (60 min), SBI offers FLUOROCET (Cat# FCET96A-1-SBI), based on direct measurement of the activity a known exosomal protein, Acetylcholinesterase (AChE).
The kit is also available in a colorimetric version, which is even faster (20 min) with a sensitivity of 50 ug protein equivalent input amount: The EXOCET™ kit (Cat# EXOCET96A-1-SBI).
For sensitive, antibody-based quantitation, SBI´s ExoELISA™ kits (Cat# EXOEL series) enable quantitation of three well-characterized exosome markers–CD9, CD63, or CD81.
FLUOROCET, EXOCET and ExoELISA are all fully compatible with exosomes isolated by SBI’s ExoQuick™ or ExoQuick-TC reagents as well as ultracentrifugation and immunopurification methods.

FLUOROCET - Exosome Quantitation When Samples Are Limiting
• Sensitive: Requires as little as 500 ng of exosomal protein
• Perfect for clinical samples or any situation where samples are limiting
• Fast—complete assay based on AChE activity in exosomes: only sixty minutes
• Versatile—compatible with all major exosome isolation methods (e.g. ExoQuick, ultracentrifugation, ultrafiltration, and immunoffinity capture)
• Quantitative—internal assay standards enable estimation of exosome abundance
Enabling highly sensitive quantitation of exosomes in only 60 min, the FLUOROCET™ kit (Cat# FCET96A-1-SBI) takes SBI´s popular EXOCET assay (see below) and increases the sensitivity over 30-fold (Click on DETAILS in the product table below to see data).
Fully compatible with all of SBI’s ExoQuick™ exosome isolation reagents as well as ultracentrifugation, FLUOROCET is great for quantifying exosomes when samples are limiting. Like EXOCET, FluoroCet measures the activity of acetecylcholinesterase (AChE), a known exosome protein, whilst the more sensitive FLUOROCET assay relies on fluorescence at 495 nm. To enable estimation of exosome abundance in your target sample, each kit includes a standard curve calibrated to known amounts of human exosomes as determined by NanoSight analysis. The FLUOROCET kit contains all of the reagents needed to perform 96 reactions.
EXOCET - Quantitate exosomes in only 20 minutes
• Quantitate exosome particles isolated from your samples
• 20 minutes assay based on AChE activity in exosomes
• Highly sensitive detection
The EXOCET exosome quantitation kit is designed as a direct measurement of Acetyl-CoA Acetylcholinesterase (AChE) activity known to be enriched within exosomes (Savina, 2002 and Gupta, 2007). SBI has also confirmed that AChE is highly enriched in exosomes from serum, stem cell, cancer cell line and MSC exosomes by Mass Spec studies and Western blots. The EXOCET assay is compatible with exosomes from all mammalian species tested (Human, Mouse, Rat) and works with exosomes isolated using ExoQuick, ExoQuick-TC, ultracentrifugation, immunoaffinity purification and chromatography methods. The EXOCET exosome quantitation system is an enzymatic, colormetric assay read at OD405. The assay is rapid, only 20 minutes from start to finish and highly quantitative. A standard curve that has been calibrated to isolated exosomes by NanoSight analysis is included in the kit that enables measuring the number of exosomes in your samples. The EXOCET96A-1-SBI kit contains all of the necessary reagents and an optical 96-well plate to perform 96 reactions.
EXOCET Sample Data
Exosomes were isolated from either human serum (0.5 ml) or from MDA-MB-231 culture media (10 ml) using standard ExoQuick and ExoQuick-TC reagents. The exosome pellets were resuspended and protein concentration measured (about 10^8 exosomes, 2ug/ul). The exosomes were lysed using the EXOCET gentle lysis solution as to preserve the enzymatic activity of the exosomal AChE enzyme. A standard curve was generated using known numbers of exosomes (as measured by NanoSight) and calibrated with a recombinant AChE enzyme standard solution provided in the kit.

References:
Savina A, Vidal M, Colombo MI. The exosome pathway in K562 cells is regulated by Rab11. J Cell Sci. 2002 Jun 15;115(Pt 12):2505-15.
Gupta S, Knowlton AA. HSP60 trafficking in adult cardiac myocytes: role of the exosomal pathway. Am J Physiol Heart Circ Physiol. 2007 Jun;292(6):H3052-6. Epub 2007 Feb 16.
The Exosome ELISA Kits are designed for the fast and specific quantitation of CD9-, CD63- or CD81-positive exosome microvesicles. Exosome standards are included for the generation of calibration curves and are provided in number of exosome particles as determined by NanoSight nanoparticle tracking analysis.
Exosome ELISA Kits are fully compatible with exosomes isolated using ExoQuick or ExoQuick-TC Exosome Precipitation Solution, see link below, as well as ultracentrifugation methods.

How it works
The ExoELISA Kit is designed as a direct Enzyme-Linked ImmunoSorbent Assay. The exosome particles and their proteins are directly immobilized onto the wells of the microtiter plate. After binding, wells are coated with a block agent to prevent non-specific binding of the detection antibody. The detection (primary) antibody is added to the wells for binding to specific antigen (e.g. CD63) protein on the exosomes.
A Horseradish Peroxidase enzyme (HRP) linked secondary antibody (goat anti-rabbit) is used for signal amplification and to increase assay sensitivity. A colorimetric substrate (Extra-sensitive TMB) is used for the assay read-out. The accumulation of the colored product is proportional to the specific antigen present in each well. The results are quantitated by a microtiter plate reader at 450 nm absorbance and calibrated by the exosome standards provided in the kit. The exosome standards are provided in number of exosome particles as determined by NanoSight dynamic light scattering measurements.

Quantitation of serum exosomes using the CD63, CD9 or CD81 ExoELISA Kit.
Exosomes isolated from serum using ExoQuick Exosome Precipitation Solution were analyzed by the respective ExoELISA Kit. The results are quantitated by a microtiter plate reader at 450 nm absorbance and calibrated using the exosome standard provided in the kit.
New:
ExoELISA-ULTRA
Improving on the popular ExoELISA™ kits, the ExoELISA-ULTRA CD63 and CD81 kits (cat# EXEL-ULTRA-CD63-1-SBI & EXEL-ULTRA-CD81-1-SBI ) increase the sensitivity of exosome detection—as low as 1 µg protein equivalent—while shortening the total assay time to only 4 hours. Currently configured for detection of CD63 and CD81, widely recognized and popular exosomal markers, ExoELISA-ULTRA CD63 and CD81 are based on an ultra-sensitive, direct capture, colorimetric ELISA assay that is compatible with nearly all biofluids. The ExoELISA-ULTRA CD63 and CD81 come with an internal standard calibrated to exosomes from a range of biofluids by NanoSight analysis to enable estimation of exosome abundance in your target samples. One ExoELISA-ULTRA CD63/CD81 kit contains all of the necessary reagents (including assay plate) to perform up to 96 reactions.
• Sensitive—detection as low as 1 µg protein equivalent
• Fast—complete in less than 4 hours—no more overnight incubation
• Flexible—compatible with all major exosome isolation methods (e.g. ExoQuick™, ultracentrifugation, ultrafiltration, and immunoffinity capture)
• Quantitative—calibrated internal standards enable estimation of absolute exosome abundance
• Sample-saving—requires significantly less sample than the standard ExoELISA kits, leaving more for other downstream applications

The standard curve for ExoELISA-ULTRA CD63 provides robust linearity down to ~1x10e9 exosomes.

ExoELISA-ULTRA CD81 standard curve shows robust linearity down to ~4 x 10e9 exosomes. OD450nm values of commonly used samples (e.g. human serum, HEK293T, and MCF7 breast cancer exosome lysates – in large colored dots) fall well within the standard curve for the assay.
Related Links
ExoQuick Exosome Isolation Kits
Exosome Antibodies
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Brochure Exosome - Research, Products and Services
Description | Cat# | Size | Price | ||
---|---|---|---|---|---|
FLUOROCET Exosome Quantitation Kit (High Sensitivity Exosome Quantitation by AChE Activity Measurement) | FCET96A-1-SBI | 96 reactions | 705 € | DETAILS | Add to Cart |
EXOCET Exosome Quantitation Kit (Rapid Exosome Quantitation by AChE Activity Measurement) | EXOCET96A-1-SBI | 96 reactions | 517 € | DETAILS | Add to Cart |
EXOCET Standard | EXOCET-SD-1-SBI | 1ml | 256 € | DETAILS | Add to Cart |
ExoELISA-ULTRA Complete Kit (CD63 detection) | EXEL-ULTRA-CD63-1-SBI | 96 reactions | 691 € | DETAILS | Add to Cart |
Exosome ELISA Complete kit (CD63 detection) | EXOEL-CD63A-1-SBI | 96 reactions | 771 € | DETAILS | Add to Cart |
ExoELISA-ULTRA Complete Kit (CD81 detection) | EXEL-ULTRA-CD81-1-SBI | 96 reactions | 691 € | DETAILS | Add to Cart |
Exosome ELISA Complete kit (CD81 detection) | EXOEL-CD81A-1-SBI | 96 reactions | 771 € | DETAILS | Add to Cart |
Exosome ELISA Complete kit (CD9 detection) | EXOEL-CD9A-1-SBI | 96 reactions | 771 € | DETAILS | Add to Cart |
96 Well ExoELISA plate | EXOEL-96P-1-SBI | (12x8 well strips, pack of 10 plates | 231 € | DETAILS | Add to Cart |
Exosome binding buffer for ELISAs | EXOEL-BB-20-SBI | 20 ml | 240 € | DETAILS | Add to Cart |