Superior Performance for today’s most challenging stem cell applications – Introducing Gibco™ StemFlex™ Medium

Which Pluripotent Stem Cell Culture Medium is right for you?

This is one of the most challenging questions facing researchers looking to expand their Pluripotent Stem Cell Research and downstream applications. Traditional media formulations for the culture of pluripotent stem cells (PSCs) were originally designed over a decade ago when the most important questions researchers were asking were about how can they reproducibly derive and maintain these cells.

Over the course of the last ten years, the use of PSCs has expanded exponentially to more complex and intricate applications, including single-cell passaging and gene editing. Using the original culture media, researchers have had difficulty keeping up with the technological advances of the field when these media do not support the desired applications.

Until now, there have been many protocol recommendations for traditional PSC media; however, these still leave significant performance gaps in next-generation applications of PSCs such as genome editing. In addition, these various protocol adjustments have created a new problem—inconsistent performance between researchers—making it difficult to reproduce results within and across labs.

Over the past decade, the stem cell research community has been branching out beyond conventional approaches to more innovative technologies and applications, including genome editing and single-cell analysis. While these novel applications enable significant advancements in relevant physiological disease models, they put significant stress on stem cells, often impacting cell survival.

Pluripotent stem cell (PSC) research requires careful attention to culture conditions. Gibco™ media and reagents have been at the forefront of pluripotent stem cell research for years and this year Gibco™  has launched its newest formulation  - Gibco™ StemFlex™ Medium.

Gibco™ StemFlex™ Medium

Gibco™ StemFlex™ Medium supports the robust expansion of feeder-free pluripotent stem cells (PSCs) and is optimized to support novel applications, including single-cell passaging, gene editing, and reprogramming. StemFlex™  Medium’s unique formulation offers the convenience of a flexible feeding schedule (including weekend-free options) and also the ability to choose the matrix and passaging reagent that best suits specific applications. StemFlex™ Medium enables the long term feeder-free culture of PSCs without karyotypic abnormalities and maintains the cells' ability to differentiate into all three germ layers. 

Gibco™ StemFlex™ Medium is uniquely formulated to support cells through these stressful transitions while delivering consistent results and superior performance when compared to  traditional media.


Key Advantages of Gibco™ StemFlex™ Medium

Superior results:

StemFlex™ Medium is formulated to deliver superior outcomes in today’s more-challenging applications that stress PSC cultures, such as reprogramming, single cell passaging, and gene editing. StemFlex™  Medium provides superior cell survival compared to the leading competitor (mTeSR1), allowing for greater success in the most relevant cell types.

StemFlex™  Medium allows for unprecedented 3-way usage flexibility for PSC culture conditions: the ability to select an optimal feeding schedule, including a weekend-free option; a choice of matrices, depending upon the needs of the workflow; and the option to select the passaging reagent for the level of cell dissociation required.

Exceptional value and performance:
StemFlex™   Medium is provided in a convenient two-component kit (450 mL basal medium & 50 mL supplement), and when used with Geltrex™ LDEV-Free, hESC-Qualified, Reduced Growth Factor Basement Membrane Matrix, provides a cost-effective, robust system for superior feeder-free culture of human PSCs. StemFlex™   Medium’s ability to enable weekend-free culture of PSCs provides unmatched value among the robust feeder-fee PSC media on the market.

There are a number of very useful resources available to support researchers in their transition to using Gibco™ StemFlex™ Medium


  • And of course samples! – contact Bio-Sciences today to avail of your  StemFlex™ sample

Transition to using Gibco™ StemFlex™ Medium

As with all transitions to new culture media there are a number of considerations which have to be taken into account, below are a number of key questions that have been posed by researchers

Q. Can the reconstituted StemFlex Medium be frozen for later use in usage-size aliquots?

A. Yes : Following reconstitution, the complete medium can be aliquoted and stored at –5°C to –20°C for up to 6 months. Alternatively, single-use aliquots of the supplement can be made and frozen at –5°C to –20°C. However it is recommend to avoid multiple freeze-thaw cycles.

Q. How does StemFlex Medium compare to mTeSR1 and TeSR™-E8™ media?

A. StemFlex Medium is a more robust medium than TeSR-E8 medium and has fewer components than mTeSR1 medium. Performance of StemFlex Medium was shown to be superior to that of mTeSR1 medium in a number of applications, including single-cell passaging, gene editing, and Reprogramming.

Q. How difficult it is to adapt cells from another PSC medium, like mTeSR1  medium, to StemFlex Medium?

A. Adaptation of cells to StemFlex Medium from another PSC medium is simple and straightforward. For optimal results, we recommend a twopassage adaptation into StemFlex Medium. If cells are cryopreserved in mTeSR1 medium on Matrigel matrix, we recommend thawing cells back into the mTeSR1/Matrigel medium until fully recovered, then follow adaptation of cultures to StemFlex Medium using Versene solution for clump passaging.

Q: If I am not interested in the weekend free feeding schedule, can I still feed my cells daily?

A: Yes  StemFlex Medium will accommodate most feeding schedules, including every day and weekend-free. There is a full list of recommended feeding schedules available on go to

Q. For gene editing and/or flow sorting experiments, can antibiotics be used to prevent contamination?

A. Yes  Antibiotics can be used within the StemFlex system to support gene editing and flow sorting. Gibco™ Antibiotic-Antimycotic (100X) (Cat. No.15240096) is recommended.

Q.  Is StemFlex Medium xeno-free and/or defined?

A. The formulation of StemFlex Medium includes bovine serum albumin (BSA) and thus is not onsidered xeno-free. It is more defined than mTeSR1 medium, as it contains fewer components in the formulation. 

If you have any further questions or i can be of any further help, please do not hesitate to contact me.

Jane Fitzgerald,

Product Specialist

BioSciences Limited

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