Exotest / Exofacs

Exotest / Exofacs

What are other methods of exosome quantification?

Other than ExoTEST and Exo-FACS kits, once can use Electron Microscopy (based on particle size and hence distinguishes between exosomes and other vesicles), Nano Tracking Analysis (optical microscopy based approach to quantify small particles like exosomes) and qPCR analysis for snRNA U6, snoRNA U38B, and snoRNA U43 (quantification based on RNA).

Quantification of exosomes using standard FACS instruments is not possible due to the small size of exosomes: How does your Exo-FACS quantification system works?

After Exosome isolation, the purified exosomes are bound to the 4 µm aldehyde sulfate latex beads (FACS-Beads) followed by the exosome marker characterization via FACS analysis using exosomes specific antibodies.

Exosome characterization using ELISA can be targeted on external protein epitopes on the vesicle. What is the sensitivity of your ELISA assays and how do you recognize the internal proteins?

ExoTESTTM ELISA kits are double sandwich ELISA kits that consists of ELISA plates pre-coated with proprietary exosome.

Quantification of exosomes using standard FACS instruments is not possible due to the small size of exosomes: How does your Exo-FACS quantification system works?

After Exosome isolation, the purified exosomes are bound to the 4 µm aldehyde sulfate latex beads (FACS-Beads) followed by the exosome marker characterization via FACS analysis using exosomes specific antibodies.

Exosome characterization using ELISA can be targeted on external protein epitopes on the vesicle. What is the sensitivity of your ELISA assays and how do you recognize the internal proteins?

ExoTESTTM ELISA kits are double sandwich ELISA kits that consists of ELISA plates pre-coated with proprietary exosome antibodies thereby enabling specific capture of the external epitopes using different biological samples. The detection limit of an ELISA assay is lower than 0.35 µg of overall exosome which is an equivalent of less than 50 pg of targeted exosomes protein. Additionally, detection of external epitopes can be also done by FACS analysis. For internal proteins, we recommend western blot analysis. You can also detect internal proteins via FACS analysis after exosome permeabilization.

For the HansaBioMed FACS kits, CD9 or CD63 antibody is used. Are these FITC conjugated or what is the dye the antibodies are conjugated with?

In Exo-FACS assay kits, antibodies are not conjugated. We provide a secondary antibody Alexa 488.

Can I use heparin or EDTA tube to collect blood sample if I need to isolate exosome from plasma?

No. Heparin will significantly impair the downstream RNA assays, and also the quantification using ExoTEST.