Rapid Clear® Cap

A revolutionary new technology that allows high speed clarification of cellular material


Clarify 3L of Cell Culture In < 30 Minutes

with no centrifugation required

Revolutionary Technology In Downstream Processing

The Thomson Optimum Growth® System of products is expanding into downstream processing with a revolutionary new technology that allows high speed clarification of cellular material. Thomson developed the Rapid Clear® Cap to address the needs of scientists to quickly and efficiently clarify cell culture media directly from the Thomson 5L Optimum Growth® shaker flask without the need for centrifugation.


Features & Benefits

Key Features
  • Depth filtration with a 0.2μm final pore size eliminates multiple filtration steps and in most cases centrifugation

  • Significant time savings versus traditional spin down technique

  • Cell culture clarification of low or high density cultures of CHO stable, CHO transient, HEK293, hybridoma, and other mammalian cell lines

  • Eliminates transfer steps: The Rapid Clear® Cap screws directly onto the Optimum Growth® Flask

  • Secondary cap attaches to a new Optimum Growth® Flask or to a storage container with a Luer lock

Key Benefits
  • Save time, clarify 3L of cell culture in less than 30 minutes - with no centrifugation required!

  • Reduce consumables used by up to 90%

  • Walk away convenience and safety - minimize endotoxin exposure

See Rapid Clear® Cap in Action!

Simply switch out the vented Optimum Growth® Cap for the Rapid Clear®. The only equipment required is a peristaltic pump. In initial testing the units can filter up to 2.5L-3L of high density culture, 6x10^6 -20x10^6 @ >70% viability, in approximately 18 minutes. This technique will transform the time consuming and laborious task of harvesting cells to a rapid walk away procedure.

Win Your Day Back

with Faster Filtration!

Time in Minutes

Clarify your cultures in under 30 minutes


CHO & HEK293 Filtration

Quick cell harvest for mammalian cells

Less Components Needed

= Less Waste

Current Method

  • 4 x filter funnels
  • 6 x containers
10 items
+ centerfugation needed

New Method

  • 1 x Optimum Growth® Flask
  • 1 x Rapid Clear® Cap
Only 2 items needed

A Comparison

Rapid Clear® Cap 3000 to GE® Capsule Filters

HPLC was utilized to quantitate intact protein for each of the purified solutions. The Rapid Clear® System yielded a slightly higher quantity of intact IgG, than the GE capsule columns.


HPLC comparison of the purified IgG. The Rapid Clear® Cap 3000 is the red line and GE the blue line

Both GE and Rapid Clear® clarified IgG were run on an SDS Page gel for comparison: Lanes 1 & 4 are molecular weight standard ladder; Lanes 2&3 are non-reduced; lanes 5&6 are reduced.

  • 1 ug of post proA protein per lane
  • Both Reduced and Non-reduced samples
  • 4-12% Bis Tris Gel from Life Tech
  • Run in MES buffer @ 200 V for 30 minutes
  • Stained with Safe Stain
  • Ladder is Precision Plus from Biorad

A= GE filtered material
B= Rapid Clear®filtered material


Rapid Clear® Cap 3000 Protocol

Reduce Operating Costs by Increasing Efficiency & Minimizing the Number of Consumables Used

When producing biologics, cell yield and viability, and effective clarification are critical. Thomson's patented Optimum Growth® Flask design facilitates good mixing and high gas exchange rates to produce high density yields of viable cells. Thomson has used its expertise in filtration to develop the Rapid Clear® Cap 3000 to speed up the clarification process. This innovation reduces operating costs by increasing efficiency and minimizing the number of consumables used.

Quick & Easy to Use

Using the Rapid Clear® Cap 3000 is quick and easy. Once the mammalian or insect cell culture is ready for clarification, simply remove the vent cap and replace it with the Rapid Clear® Cap 3000. The chart provides the approximate time*** to clarify cell cultures based on cell type, viability and volume to be filtered. The higher the viability the faster the filtration.

  • Grow cells in a 2.8L or 5L Optimum Growth® Flask

  • Transfer the flask to a hood to replace the Vent Cap with the Rapid Clear® Cap

  • Replace the Vent Cap on the receiving 1.6L, 2.8L, or 5L Optimum Growth® Flask with the receiving cap that comes with the Rapid Clear® Cap

  • Remove from hood and place tubing in the pump head, see pump recommendations***

  • Tilt the flask slightly and run the pump at maximum speed until only a few hundred mL remain

  • Add 400mL of PBS to the Optimum Growth® Flask to ensure all the culture has been filtered and transferred to the new flask


Duplicate 3L CHO Stable cell cultures were clarified using the Rapid Clear® 3000. This graph compares the volume clarified over 21 minutes.

Volume & time recommendations by cell type
Cell Line Viability99%-70%69%-50%49%-40%39%-0%
Spin for 7min @ 4000g*
Cell TypeVolume
CHO Stable without Feed3.0182.5182.0203.5****35****
CHO Stable, 1 to 2 Feeds2.0182.0181.535
CHO Stable, 2+ FeedsSpin for 7 min @ 4000g; ≤3L volume ****
HEK293 (FreeStyle™ & Expi293)3.0183.0233.0253.5****35****
CHO Transient3.0182.5181.535

* For low viability cultures, (< 39%), centrifuge for 7 minutes prior to clarifying with the Rapid Clear® Cap.
** This chart was created from results generated in customer labs.
*** All data was generated using a Cole-Parmer pump (pump drive p/n EW-07554-90, pump head p/n EW-77200-62)
**** Cell cultures that received 2+ feeds will require spinning to minimize potential clogging

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Rapid Clear® Part Number

Optimum Growth® Flask Part Numbers