ExoQuick Q&A

Q. Do EVs secrete nucleocapsids into the bloodstream?
A. Given the currently available literature on the point, we know that while nucleocapsids can be found inside of EVs, they aren’t secreting them.

Q. What’s the size of the vesicles that you can recover with ExoQuick ULTRA?
A. Depending on the prep, between 70-200 nm.

Q. What’s the best way to isolate EVs from culture media?
A. This answer depends on the downstream applications you’re going to use with your exosomes; this will alter your methodology. Importantly, we have a version of ExoQuick ULTRA that’s specifically designed for tissue culture media and fluids that are less abundant, like CSF or urine. This version is called ExoQuick ULTRA TC.

Q. Can ExoQuick be used for functional EV isolation?
A. Yes, definitely. This is the express purpose of ExoQuick ULTRA.

Q. What would be the best system to use when trying to obtain enough small RNAs from EVs for library preps, for NGS?
A. ExoQuick ULTRA would be a very good choice in the sense that you’re getting rid of background proteins, so you have a much cleaner prep while simultaneously increasing yield.

Q. How many milliliters are required for human serum?
A. You can start with 100-250 microliters.

Q. Does ExoQuick have a high throughput format, like a 96-well format for serum?
A. We don't have this yet. We understand that for clinical applications it makes things much easier, but actually, it is even better to tackle many samples with a precipitation-based approach than relying upon ultracentrifugation or other approaches.

Q. What is the range or heterogeneity of EV size in different samples?
A. The range of EV size is quite heterogenic as it includes exosomes and microvesicles that all vary in size from 70-250 nm. There’s no specific cut-off for exosomes or microvesicles with respect to differences in size between the two.

Q. Do you treat the exosome prep with proteases before isolation in order to eliminate contaminating proteins?
A. No. In general, proteases won’t eliminate the contaminating proteins and there’s no good reason to add more proteins to your isolation procedure either.

Q. How would you dissolve an exosome pellet in PBS; as they can be difficult to dissolve?
A. While it may take 1-2 minutes of pipetting, even the hard-to-dissolve pellets will be able to dissolve.

Q. Do you recommend confirming EV markers with TM?
A. For general exosomal or EV markers, western blotting is just fine. In very particular applications, you may want to perform immunogold staining with TM with any specific biomarkers that you have identified.

Q. Are exosomes stable?
A. In terms of stability with respect to pH or proteases, they are very stable.

Q. Can ExoQuick ULTRA be used for the isolation of a specific size of EVs?
A. ExoQuick cannot discriminate between the different types of EVs. It isolates a heterogenic population of EVs.

Q. Where can I get the images found in this ebook?
A. If you want a copy of the images, please send us an email to tech@systembio.com