All biological samples are complex and the user must optimise the protocols for their own biological particles systems. Some raw samples cannot be directly run on a qEV and analysed with TRPS without further preparation steps, such as two or more stages of centrifugation to prepare the sample (e.g. blood, saliva) or a concentration step (cell culture, urine).
For some biofluids with lower levels of EVs and proteins, the sample can be concentrated before application to qEV columns to enable larger volumes to be processed (not applicable to serum and plasma that have very high levels of protein and cannot be readily concentrated). The exact protocol may require modification depending on the sample, its viscosity and other preparation steps.
Below is an example protocol for preparation of extracellular vesicles from more dilute samples e.g. cell culture samples or urine:
If the TRPS analysis is problematic because of blockages due to large aggregates we recommend post qEV clean up of EV samples with the use of Millipore spin filters (Ultrafree-MC centrifugal filter units 0.22 μm).