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F.A.Q. Section
Please click on the links below to view the FAQ answers. We hope this section provides answers to your queries. If you have any additional concerns, please contact us at to receive technical support.

General Questions
Sales Questions
Culture Plate Questions
Technical Questions


General Questions

How is strain applied to the cells?
Strain is applied to cells via vacuum deformation of the silicone elastomer growth substrate in the rubber-bottomed culture plates as depicted in the schematic below (Figure 1). Please also see our applications page about Applying Mechanical Load to Cells in Monolayer Culture and Tech Report 101: Loading Stations™. Quantification of Strain on the Membrane Surface for further information.

Equibiaxial Strain
Figure 1. Equibiaxial strain application to cells plated in a BioFlex® well.

Which plates are used for equibiaxial tension and which plates for uniaxial tension?
BioFlex®, HT BioFlex®, and Circular Foam Tissue Train® plates can be used during application of equibiaxial tension.

Linear and Trapezoidal Tissue Train® plates as well as UniFlex® plates are used during application of uniaxial tension.

Which plates are used for monolayer culture and which plates are used for 3D culture?
BioFlex®, HT BioFlex®, and UniFlex® plates are used to culture cells in monolayer.

Tissue Train® culture plates are used for creating 3D bioartifical cell-seeded constructs.

What are the strain ranges for the various culture plates and Loading Stations™?

Strain Table
Table 1. Strain values that can be achieved in 6-well culture plates strained with the FX-6000™ Tension System.

How can I find out what type of research has been conducted with Flexcell® equipment and my cells or tissue?
Flexcell® has a Publication Database on our publications page that lists the bibliographies for some of the research conducted using our equipment. The list is categorized by type of equipment used and by cell type.

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Sales Questions

Can I test your equipment in my laboratory?
If your lab is located in the USA or Canada, we offer a 6-week complimentary trial period for all equipment.

Can I lease your equipment?
If your lab is located in the USA or Canada, we have 6 and 12-month renewable lease options. Please contact Flexcell®'s Sales Department at for further information.

Does Flexcell® accept orders worldwide?
Flexcell® products are sold worldwide. Flexcell® International serves the USA and Canada. Europe is served by Dunn Labortechnik. Bio Excellence International Tech Co., Ltd. serves China, Hong Kong, and Malaysia. Taiwan's distributor is Nature Opera. South Korea distributor is LeeBaeg Scientific Co.,Ltd . Brazil's distributor is Sellex. Customers from these regions should contact their local distributor for all order inquiries.

What forms of payment can I use to purchase consumables on-line?
Flexcell®'s on-line store only accepts credit card payments. If you wish to use another form of payment, please contact Flexcell® directly.

Does Flexcell® ever offer any sales on equipment and consumables?
Yes! Flexcell® periodically has sales on equipment and consumables. Please contact Flexcell®'s Sales Department at for current promotions or check on our promotions webpage.

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Culture Plate Questions

I purchased some culture plates but I need to contact you for a software patch. Why do I need a software patch?
The plates you received have a different calibration file from previous plates. If your system has not been updated with the new calibration files, they you will need to contact Flexcell® to get the software update for your system. Please be sure to include your unit serial number when contacting Flexcell®.

Can BioFlex® plates be used with electron microscopy?

How do I know which culture plate coating to use with my cells?
Please see Tech Report 106: Matrix Bonded Growth Surfaces. Growing Cells in a More Natural Matrix Environment, which discusses the various matrix coatings available on Flexcell®'s culture plates.

How do I clean the silicone grease from the bottom of the silicon membranes?
The grease can be removed with the following protocol after the cells have been fixed:

  1. Using a dry cotton swab, wipe off as much of the excess lubricant as possible. This may require a couple of swabs. Only a thin film of lubricant should remain on the membrane surface.
  2. Wet the tip of a new cotton swab with a mild cleaning solution such as Formula 409, window cleaner, or hand soap. Rub the wet swab gently over the entire surface of the well. Repeat with a new cotton swab and fresh cleaning solution as necessary to remove all residual lubricant from the membrane surface.
  3. Rinse the cleaned surface with deionized water using a spray, wash, or dispensing bottle.
  4. Blot the surface dry with a Kimwipe or other lint-free wipe.
Also, please see Tech Report 202 for more techniques on viewing cells on Flexcell® culture plates.

Why are the cells not attaching well to the growth surface and are detaching during stretching?
This may be caused by plating too many cells. Plate with a lower cell density. If the cells are not confluent, they will form a matrix with the collagen (or other matrix coating) attaching more securely to the growth surface.

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Technical Questions

How do I connect more than one FlexLink to the same computer?
Please see Tech Report 109: Using Additional FlexLinks® for the schematics on connecting additional FlexLinks®. Please also see the video Connecting Two Tension FlexLinks® to One Computer on our Instructional Video page.

Why am I not getting the programmed % elongation?
If you are using the FX-6000™, FX-5000™, Flex Jr.™, FX-4000™ and FX-3000 Tension System, see response below. If you are using an older model, please contact Flexcell®.

a. Try lowering the frequency of the regimen to allow the FlexLink® enough time, per cycle, to intake and exhaust the correct amount of atmosphere.

b. Check to ensure there is no vacuum leak at the baseplate:
  1. Check that the gaskets are flatly seated in the wells.
  2. Make sure all 4 baseplate wells are being used.
  3. Re-run the regimen while initially applying hand pressure to start the seal between the plates and gaskets.
  4. Place the Plexiglas cover and, if needed, additional weights (up to a total of 10 lbs) on top of the Plexiglas cover.
c. Check the Water Traps, Flex In and Flex Out tubing for any moisture collection. Connect the Drying Filter and run the Drying regimen, if needed.

d. Check to ensure that the vacuum source is producing a constant pressure of -90 to -100 kPa. If using an oil-based pump, check to ensure that the oil is not dirty.

e. Contact Flexcell® if any of the above do not resolve the issue.

Why is the regimen programmed to stretch 0-2%, but the actual output is 5-7%?
Connect the Drying Filter and run the Drying regimen (as described in the manual). If the issue still persists, please contact Flexcell®.

Why is the regimen wave fluttering or not smooth?
a. Check to ensure there is no vacuum leak at the baseplate:
  1. Check that the gaskets are flatly seated in the wells.
  2. Make sure all 4 baseplate wells are being used.
  3. Re-run the regimen while initially applying hand pressure to start the seal between the plates and gaskets.
  4. Place the Plexiglas cover and, if needed, additional weights (up to a total of 10 lbs) on top of the Plexiglas cover.
b. Check to ensure that you have downloaded your regimen to the correct Platform.

c. Check the tubing to ensure there is not a kink.

d. Check the tubing length. The tubing should be cut as short as possible with enough extra length so that the tubing is not strained.

e. Contact Flexcell if any of the above do not resolve the issue.

"An invalid argument was encountered" error is shown when attempting to assign a regimen with the FX-5000™ or Flex Jr.™ Tension System.
This error results from assigning a regimen to a user that does not have a regimen created under his/her name. Either create a regimen for the user or delete the user and re-assign the regimen to a valid user.

I received a 'Cannot Connect to Controller' message when opening the software.
a. Make sure the FlexLink® is powered ON.

b. Make sure the Ethernet cable is connected between the FlexLink® and the computer.

c. The IP address settings might have been changed by your institution upon set up in the laboratory. Please contact Flexcell® if you think this is the case.

I have an FX-4000™ and it is running Windows 95, 98 or ME. Can I purchase a new computer with a more up-to-date Operating System?
Flexcell® can upgrade your current system. Please contact Flexcell® to learn more about our options for upgrading.

Why are the gaskets on the baseplate not sealing?

a. System is not performing to specified parameters; i.e., not reaching maximum %elongation entered in regimen

b. Water trap is filling up with water quickly during use with incubator

Test to determine if this is the problem:

If you are experiencing symptom a, there could also be a leak elsewhere in the system. To narrow its location, run a regimen with the baseplate and take note of the max and min %elongations. Disconnect the quick disconnects from the baseplate and connect them together. Take note again of the max and min %elongations. They should change a little because of the decrease in system volume, but if you were originally having outputs that were significantly different from the inputs, it should go near (maybe somewhat above) your original inputs. The wave will also likely be somewhat choppy because of the low volume. If your outputs were originally only slightly lower or higher than your inputs, the problem is likely not a leak but calibration. Call Flexcell® for calibration instructions. If the output max %elongation increases significantly when the quick disconnects are connected together, the leak is most likely in the baseplate. If not, check the vacuum connections at the back of the controller.

Why is the regimen wave flatlining?
Remove the "sys" vacuum line at the back of the controller and check to be sure that there is vacuum coming through the line. Check the "vent" port at the back of the controller to see if air is moving in or out. If not, it is possible that the valves are locked or stopped up. Try applying positive pressure to the vent port to free the valves. If the "vent" port is breathing and the plates are flexing, the problem is likely with the computer and should be reported to Flexcell®.

You want to program a long regimen (ex: 1 day or more) and the software won't let you.
The software has a limit on the number of cycles that can be entered into any given step (65, 535; see page 12 of the manual). If you program a regimen with a frequency high enough to require more than 65,535 cycles to go for the amount of time that you wish to run it, the software will give you an "invalid entry" error. You will need to make an additional step to run the full regimen. This will not create any breaks in the regimen. Simply divide your total time in half (or as many times as is necessary) and make two steps with the same parameters. See page 12 of the manual for instructions on programming additional steps.

Why are the plate wells drying up during the experiment?
When vacuum is pulled to expand the silicone membranes at the bottom of the BioFlex® wells, the volume of the well increases, pulling air into the well from the atmosphere. When the membranes contract, the air is pushed back out. Because of this cyclic airflow during any experiment, the evaporation rate in the BioFlex® wells will increase. The only solution to this problem is to use more cell medium.

Why is water accumulating quickly in the water trap?
This problem is likely due to a poor gasket seal on the BioFlex® baseplate. See the solution to Problem 1 to correct this. Be sure to empty the water trap frequently if you are having this problem. Water accumulation in the controller can damage the valves. If the baseplate is sealed and the problem still continues, try placing another water trap inline for safety purposes and contact Flexcell®.

Why is water accumulating in the Flex In or Flex Out tubing?
If moisture is seen in the Flex Out or Flex In tubing coming from the baseplate in the incubator, make sure water traps are installed between the baseplate and the FlexLink® controller. Water traps should be installed at a height lower than the FlexLink®. Check water traps periodically for accumulated moisture. Empty the water traps when any water can be seen in the traps.

Moisture condensation in the tubing coming from the baseplate indicates there may be a leak or poor seal on the baseplate. Check to make sure all 4 slots of the baseplate are occupied by a gasket and BioFlex® plate. Check the perimeter of the bottom of the baseplate for any leaks due to baseplate warping. If the baseplate is warped due to prolonged exposure to high temperatures, you may need to replace the baseplate.

Moisture accumulation in the FlexLink®'s Flex In line can be caused by excessive water vapor in the atmosphere of the operating environment. If possible, monitor and reduce the relative humidity of the room where the FlexLink® is located. Relative humidity should be maintained below 40%. If moisture is seen in the Flex In tubing coming from the FlexLink®, run the drying regimen with the drying filter connected to Flex In and Flex Out ports on the back of the FlexLink®.

If moisture still accumulates in the FlexLink® tubing, contact Flexcell® for further technical assistance.

Can I use the PUMP CONTROL feature on the rear of the FX-5000™ Compression FlexLink®?
No, although there is a PUMP CONTROL socket on the rear of the FlexLink®, it is not electrically connected to the system. We do not sell a standalone air compressor but recommend using a compressed air source capable of producing 12 PSI (83 kPa) of pressure at 0.9 cfm (25.5 L/min).

Can I use different screws with the Streamer® other than the ones supplied?
Since the Streamer® is made of stainless steel, using any other screws other than the supplied brass screws will cause the screws and the Streamer to fuse together.

Why is my Streamer® leaking?
Make sure that: -
  1. All 12 o-rings (6 on the top and 6 on the bottom) of the Streamer® are present.
  2. There is Teflon tape on all threaded quick-disconnects.
  3. The top and bottom of the Streamer® are securely closed.
  4. The quick-disconnects are "locked" into place.

Why are the pulse dampeners leaking?
Leaking pulse dampeners are usually caused when the pulse dampeners have been autoclaved. The plastic becomes soft and slightly misshapen, so when the quick-disconnects are re-attached, the fit is not as tight and leakages can happen.

How do I remove the bubbles from the tubing?
  1. Shake or tap the tubing to release the air bubbles.
  2. Turn the pulse dampeners upside down and allow them to fill to full. Then, turn the pulse dampeners the correct way around and allow the medium to flow through the system.