Many different methods have been developed for preparation of EVs, before characterization. Along with generally accepted methods are some “tricks of the trade” such as the addition of Tween® or BSA; however, some of those additions are problematic, in that they create significant background particles.
The use of Tween® in low concentrations for EV sample preparation has been recommended by several vendors. The creation of background particles may come as a surprise to some researchers, where filtration before addition to a sample may not entirely solve the issue for a couple of reasons. First, many syringe filters shed particles of their own and require conditioning before filtration of any diluent; therefore, one must be careful not to compound the problem when taking this step. Second, as Tween® is essentially detergent, it is likely that the interaction of Tween® with the protein in EV samples will generate additional, measurable particles after a filtration step. We present here some simple tests to illustrate the problem.
Figure 1 shows Nanoparticle Tracking Analysis measurement of just PBS, a null set. Only three particles were tracked when using a typical SOP for EVs, so this PBS is clean. Figures 2, 3 and 4 show the effect of adding Tween® to PBS, even though the additive is only present in low amounts (0.1% and 0.3% concentrations). Notably, our ZetaView® system is too sensitive at a concentration of 0.5% Tween®, which creates so many surfactant nanoparticles that NTA analysis isn’t feasible.
Along with generally accepted methods are some “tricks of the trade” such as the addition of Tween® or BSA; however, some of those additions are problematic.
Platinum Presenter Talk at ISEV 2022 in Lyon Dr. Clemens Helmbrecht NTA is a multi-parameter technology Nanoparticle Tracking Analysis (NTA) is well known for measuring
From the same sample you get the parameters: number concentration, size, electrophoresis surface charge, sub-populations and fluorescence phenotyping in little time.
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