What pump is recommended?
We have found many pumps* in good working order will work well. The pump should be rated to be able to maintain 500rpm and accept Silicone Tubing, 3/16″ ID x 3/8″ OD x 4′.
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*Cole Parmer pump, pump drive (p/n EW-07554-90), and pump head (p/n EW-77200-62). Watson Marlow pump, (p/n 520U).
Does the filtration process require a set pump pressure?
Unlike other systems the Rapid Clear® System does not it require a manifold and constant vigilance over pressure readings. It is safe to set up, and walk away.
What size and length tubing comes with the Rapid Clear® Cap?
Silicone Tubing, 3/16″ ID x 3/8″ OD x 4′.
What viability is best for harvesting for homogeneity of proteins?
Optimal cell culture harvest conditions are approximately 70-90%. Cell Cultures under 70% viability contain proteases which chew up extra cellular proteins (component of interest), have high amounts of dead cell debris & heterogeneity in protein quality. Less than 70% viability requires additional purification steps which leads to more loss. Additional lose in purification is seen when stretching the day to get an extra 10% titer.
What size Optimum Growth™ Flask can I use for the receiving vessel?
The Rapid Clear® Cap comes with an attached secondary flask cap that will fit the following Optimum Growth™ Flasks: 1.6L, 2.8L or 5L.
What if I want to store the filtered culture?
The sterile Optimum Growth™ Solid Cap, (p/n 899600-B), will fit the following Optimum Growth™ Flasks: 1.6L, 2.8L & 5L.
We see a lot of foaming will this affect the protein?
The Rapid Clear® Cap will have foam, but after checking 1000 caps, we have not seen a degradation with foam, it is one of the “urban legends”.
Will this work with any flask?
The Rapid Clear® Cap will only work with the Optimum Growth™ Flasks.
Will this work with the 125mL, 250mL or 500mL Optimum Growth™ Flasks?
At this time, The Rapid Clear® Cap will only work the 1.6L, 2.8L, & 5L Optimum Growth™ Flasks. Rapid Clear® Caps for the 125mL, 250mL or 500mL Optimum Growth™ Flasks will be coming soon.
Is the Rapid Clear® Cap endotoxin free?
Yes, the Rapid Clear® Cap is endotoxin free. The Rapid Clear® Cap will not remove endotoxin’s that might be in the culture.
Does the Rapid Clear® filter need to be flushed prior to use?
The Rapid Clear® filter does not need to be flushed prior to use. It comes out of the bag ready to go.
Can I reverse the pump flow?
The Rapid Clear® filter is not designed for reverse flow. Do not run the pump in reverse.
What do I do when the Rapid Clear® filter appears to be clogged?
Once the maximum cell capacity of the Rapid Clear filter has been reached it will need to be replaced with a new Rapid Clear filter. After replacing the filter ensure the flask contents have not settled prior to restarting the pump. Please note we recommend stopping the unit at 35mL/minute.

Best Practices

Cells went down last night, can the culture be refrigerated at 4°C to keep high viability and Rapid Clear® in the Morning?
Do not allow the culture to sit on the bench for a long time prior to using the Rapid Clear® Cap. If needed, store culture in a refrigerator prior to use.
Cells went down last night can we refrigerate at 4°C high viability for Rapid Clear in the Morning?
We have many customers who instead of letting cells go to low viability, put the flasks into the refrigerator at 70%+ viability, and then harvest in the morning.
For best filtration, minimize air bubbles.
It is best to keep air bubbles to a minimum during the filtration process. Air bubbles can be avoided by ensuring the dip tube end is submersed in the cell culture prior to starting the pump. Ratchet the clamp prior to starting and stopping the pump.
Ensure all the culture is filtered and to alleviate potential clogs.
When the last few hundred milliliters remain in the Optimum Growth™ Flask, placing a wedge under one side of the Optimum Growth™ Flask to allow the dip tube to be immersed in the culture until it is empty; ratchet the clamp, stop the pump and add 400-500mL of PBS. This will ensure all the culture is filtered.

Thomson is not affiliated with Cole Parmer, Watson Marlow or their products.