Hello Adi Lahiani

You need to use the final extracted exosomes after ultracentrifugation. You can resuspend the exosome pellet obtained after ultracentrifugation in minimum quantity of PBS.

For BCA you will require 100ul of extracted exosomes if you are using the test tube method. If you are using the normal standard protocol you will require 50ul of extracted exosomes. For microplate method, 25ul of extracted exosomes is more than sufficient.

Just a suggestion.

Exosomes are membrane-bound extracellular vesicles. Quantifying exosomes using BCA is incorrect. If you want to quantify exosomes you need to use Electron microscopy, which will allow you to determine particle size and therefore distinguish between exosomes and other vesicles or

Nano sight, which is a special optical microscopy adapted to quantify small particles like exosomes.

But if you want to quantify exosomal proteins then you will have to lyse the exosomes with an appropriate lysis buffer at 4 degree C and quantify the protein content using BCA.

Best.

Hi Adi Lahiani !

In our laboratory we perform the BCA assay on the extract obtained after isolation (in our case we use SEC isolation). We take 20 ul of the isolated sample in duplicate (40 ul in total).

I hope you find it helpful

Regards :)

For quantifying Exosome, NTA is perfect choice, while if you want to determine the protein contents of the exosome then BCA should be done. For BCA we use 10ul exosome sample, adding 200ul BSA solution and to obtain accurate result we sample Exo 3*10ul for 96well plate, read it through microplate reader, and compare the result with the standard. So you will need 30ul of exosome's final extract for BCA.

Good luck.