When would you recommend cassettes or centrifuge?
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When we’re talking about lab research applications this largely comes down to what your sample volume is. The Vivaflow cassettes that operate by tangential flow filtration (TFF) for example provide the optimal recovery and speeds of concentration from the 100mL to 5L range. Less than 100mL and you find centrifugation options generally provide the best recoveries. Cost efficiency applies to this also, as it’s a lower device cost and time cost by using a single Vivaflow 50 cassette for 150ml than 10x Vivaspin Turbo 15 devices for example.
However, there are method-specific attributes that apply for both. For example, TFF devices can perform concentration at a consistent transmembrane pressure (TMP), whereas centrifugal concentrators tend to start with a high TMP then decrease as the process goes on. A changing TMP can have an impact on a particularly sensitive proteins stability and means there are more variable shear forces. However, happily the Sartorius Vivacell 100 that works with a 20-100ml volume range can be pressurized as well as centrifuged. When pressurized a far more consistent TMP is applied and so these are well suited for the concentration of protein complexes due to the low and regulated shear forces. Further to this TFF devices can be used for general clarification of the filtrate techniques.
Centrifugal devices on the other hand often come in a wider range of style and MWCOs, stretching from 2K MWCO with our patented Hydrosart membrane, to our PES 1,000K MWCO and 0.2um membrane types. Further to this, there are a number of centrifugal devices that are designed for specific applications, such as the Vivacon range that are designed for DNA concentrations, the Centrisart range which is optimal for filtrate recovery and Vivaspin Endotest which allows for the complete retention of endotoxins.
Finally, centrifugation is generally considered easier as most have a centrifuges around the lab and most crossflow devices are manufactured for the bioprocessing industry and so require high capex and fiddly mounting systems. Although happily that’s not the case anymore with the plug in and play Vivaflow devices, that just require a peristaltic pump.
In summary, it depends on your sample volume, specific application and protein sensitivity.
This post is sponsored by Sartorius.