FAQ

Q.

Why was L-Glutamine eliminated from many of your formulas?

A.

L-Glutamine is easily hydrolyzed in liquid and by-products of hydrolysis can be toxic to the cell. Additionally, the necessary concentration of L-Glutamine may be compromised after a period of time. Since L-Glutamine is an essential amino acid, it is best for the end-users to supplement media with the recommended concentration of fresh L-Glutamine.

Q.

What effects could freezing and thawing have on my sera?

A.

We generally discourage multiple freezing and thawing of sera. Sera contain proteins, lipids, and other components that may be differentially separated or precipitated out of solution, depending upon the rate of thawing or freezing. This may adversely affect the performance of the sera. The best storage is in a freezer at -20°C or lower.

Q.

How do we prevent mycoplasma contamination in cell culture?

A.

Good aseptic techniques should be used in all laboratory applications. The best method for prevention is to test all materials that come in contact with the cells. This should be done on a regular basis to ensure that mycoplasma is not introduced into the cell culture and to identify any potential sources of contamination.

Q.

When adapting cells from serum-containing to serum-free media, is the direct or sequential adaptation method better?

A.

The sequential adaptation method is recommended. When cells are transferred to serum-free medium from a serum-rich environment, the cells are deprived of components in the serum-rich environment. Sequential adaptation allows the cells to gradually adapt to their new serum-free environment. Below is an example protocol. Cell types vary. Contact us for a tailored solution.

Suggested Sequential Adaptation Protocol:

  1. Start with cultures (suspension or adherent) that are at maximum cell density and high viability (>80%). If cells are attachment-dependent, trypsinization procedures should be used.
  2. Split cells 1:2 using the desired final serum-free medium as the diluent.
  3. Incubate cells until the maximum cell density is achieved.
  4. Split cells again. The ratio may vary depending on whether the cells are growing attached or in suspension culture. For attached cells, try 1:2 or 1:3 split based on confluency. For suspensions, try 1:3 to 1:5 or approximately 3-4x105 cells per mL.
  5. Continue incubation until maximum cell density is achieved.
  6. Monitor the growth and viability of the cells relative to cells cultured in the original or control medium. Cells that have been successfully adapted to serum-free media should have a viability greater than 85%, with a doubling time equivalent to the control medium (serum-containing or other serum-free medium) from which the culture was adapted.
  7. Low viability or poor doubling times indicate that the culture may not yet be adapted. 3 to 5 successive splits using 1:2 to 1:3 may be necessary. It is not uncommon for some cells to continue to require 0.1 to 0.5% serum.
  8. Time for adaptation to serum-free conditions will vary with the growth characteristics of the particular cell type. If at any time during the weaning process the culture viability drops below 80%, or the time to double increases significantly, weaning may have occurred too quickly. The cells may require several passages at the previous dilution before renewal of the sequential weaning process resumes.
Q.

Can you customize my serum-free media?

A.

All the formulas we offer may be tailored to meet our customers' specific requirements. Whether efforts are focused on optimizing yields or improving productivity, we can work with any lab to address specific needs.

Q.

What does Irvine Scientific have to offer in their serum-free, animal-component-free, or chemically-defined lines of media?

A.

Irvine Scientific offers many serum-free media, including products for three (3) main types of cells currently used by Biotech or Pharmaceutical companies: 293 cells, Chinese Hamster Ovary (CHO) cells, and Hybridoma cells. Within each cell line, we offer a variety of media:

HEK 293 cells:  We offer one medium formulated for optimal cell growth and viral production.

CHO cells:  We offer six (6) different formulations with three (3) feed media formulations.   All of these products are animal-component-free and are free of L-glutamine, Hypoxanthine, and Thymidine to allow for use in a variety of applications.

Hybridoma cells: We offer four (4) different formulations.

  • IS GRO™ (Catalog ID: 91105)IS PRO™ (Catalog ID: 91103) is our dual media system which comprised of low protein, serum-free media and optimal for hybridoma growth and production. IS GRO™ has been optimized for maximal hybridoma cell growth and is recommended for use during the growth phase; IS PRO™ has a very low protein concentration for use during the production phase to simplify protein purification.
     
  • HB Basal Liquid (Catalog ID: T000) is a serum-free and chemically defined medium which is designed to support the growth of murine and human hybridomas, myelomas, lymphoblastoid, and endothelial cells, as well as murine T-cell hybrids.
     
  • IS MAB-CD™(Catalog ID: 91104) is a chemically-defined, low protein medium for the growth of hybridoma and myeloma cell lines for recombinant monoclonal antibody production. This chemically-defined medium is regulatory friendly and allows for improved lot-to-lot consistency compared to other formulations that are not chemically defined.
Q.

Why should I use serum-free media?

A.

Serum-free media offer the customer better lot-to-lot consistency, because they contain fewer undefined components than media containing undefined components, such as serum. The end-user also does not need to take time to qualify lots of FBS for activity. Serum-free media are lower in protein content than medium supplemented with serum, which can simplify the purification process and increase the yield of the end-product.

Q.

What are the differences between serum-free, protein-free, and chemically-defined media?

A.

Serum-free media do not contain or require the addition of serum. Animal-component-free media are media in which none of the components are animal-derived. Protein-free media do not contain any proteins. Chemically-defined media contain components which are all known (or defined chemically).

Q.

Why would I heat-inactivate my serum?

A.

Heat inactivation is a process used to inactivate protein complement components that are present in the serum. The proteins from the complement cascade have the potential to impact or interfere with certain cellular processes.

Q.

How do we prevent mycoplasma contamination in cell culture?

A.

Good aseptic techniques should be used in all laboratory applications. The best method for prevention is to test all materials that come in contact with the cells. This should be done on a regular basis to ensure that mycoplasma is not introduced into the cell culture and to identify any potential sources of contamination.

Q.

Should I be concerned with mycoplasma in my cell culture?

A.

Mycoplasma contamination should always be a concern. Mycoplasma contamination can change the morphology of the cells and interfere with bioassays, cell growth, viability, and production.

Q.

What is the timeline on a custom formula?

A.

Customs are usually delivered to the customer between 6 to 8 weeks after we receive the final signed documents with a purchase order.

Q.

What are the minimum requirements for a custom media formula?

A.

We generally require a 100L minimum order to manufacture a custom formula. Our Express Media Service™ can make smaller non-GMP quantities to meet special investigational or development needs for our customers.

Q.

Can you customize my serum-free media?

A.

All the formulas we offer may be tailored to meet our customers' specific requirements. Whether efforts are focused on optimizing yields or improving productivity, we can work with any lab to address specific needs. Visit our Custom Media Services page for more details.