Cell culture

If you have any questions regarding our cell culture media and feeds you can find answers to the most common questions here. If you do not find what you are looking for and you need further assistance we are always here to help – just contact us.

Are your media serum- and animal component free?

Yes, all our media are serum free, animal-derived component free, hydrolysate free and chemically defined.

Are your media suitable for R&D or GMP manufacturing?

Our media are approved by ISO 9001 QMS and therefore suitable for R&D and further GMP manufacturing.

What is the shelf life of the media and feeds?

The shelf life of our media and feeds ranges from 12 to 18 months. In general liquid media have a shelf life of 12 months from the date of production, powder media have a shelf life of 18 months from the date of production. The respective shelf life for each medium can be found on the Protocol for use (PFU) of each product or on the product labels. You can find our PFUs here.

Do you provide media for adherent cells?

In general our media are not suitable for adherent cells as our media are chemically defined, free of animal-derived components and were not developed for use with sera. Added surfactants act against attachment of the cells which by using serum in cell culture for adherent cells would weaken the effect of the active ingredients. However, if you are interested in medium for adherent cells please get in touch. For cultivations with micro carriers, our media can be used depending on the specific process (just contact us if you have any specific questions). Nevertheless, we are always open to requests for customized medium solutions!

Do you provide media for insect cell cultures?

We are currently working on media products for insect cultures. Please contact us to get updates on product samples and product release or check our website frequently. Furthermore, we are always available for customized medium solutions.

Do you provide media for stem cells?

No, we do not manufacture stem cell culture media (yet) but we are always open to discuss a potential customized development. Just contact us for more information.

Which filters do you use to sterilize the liquid media?

We are using PES membranes with 0.1 µM; The filter area is: Media ~ 0.1 m²/100 L, Feed ~ 0.2 m²/100 L; cutting stroke: ~ min. 3%

What is your biggest bioreactor volume?

Since we mainly use our bioreactors for research and development purposes, we are working at lab scale (2-10 L).

Which medium is best for CHO K1 cells?

We recommend using our TCX6D or CHOlean for CHO K1 cells.

Which medium is best for CHO DG44 (dihydrofolate reductase (DHFR-)) cells?

We recommend using our TCX6D, CHOlean or TC-42 (w/o GF, w/ IGF, w/ rInsulin), but as each cell line has specific needs in terms of cell culture media it is best to screen 2-3 different media. Therefore, Xell’s TCX10D medium could be evaluated as well. Please consider your selection system and requirements of your cell lines with regard to HT supplements or other relevant components to complement potential deficiencies (e.g. when cultivating DHFR- host cells).

Which medium is best for CHO GS cells?

Our TCX10D was specifically designed to fit the needs of CHO GS cells. You can use it in combination with TCX7D feed supplement (fed-batch processes).

What is the difference between HEK ViP NB and HEK ViP NX?

Both media are optimised for the production of viral vectors (e.g. AAV, Lentivirus) and offer slightly different formulations. HEK ViP NB contains basic nutrients whereas HEK ViP NX features an increased nutrient content to support different cell lines and applications. Both media allow high cell density, high transfection efficiency and competitive titers as well as easy upscaling of your process. Both media (as well as HEK TF ) should be tested to find the optimal solution for your specific process. Please order your free samples for such testing purposes.

Do you also offer feed supplements?

Yes, we offer feed supplements for a variety of cell lines. You can find them here.

For which cell lines can I use Basic Feed and TCX7D?

TCX7D was designed together with TCX10D to fit the needs of CHO GS cells, but can also be applied for other CHO cell lines. Our Basic Feed was designed to fit a wide range of mammalian cell lines, including CHO, HEK, hybridoma cells and more.

Do you have a standard feeding strategy that we could apply in our tests?

In the protocols for use (PFU) for the respective feed you can find a generic feeding strategy to use. This will probably have to be adapted/optimized for the cell line and the process in use, especially after scaling up the process. If available, you can use glucose concentrations in your culture as an initial guideline and add feed volumes to keep glucose in a certain range (e.g. 2-4 or 2-6 g/L). Glucose concentrations of our feed products can be found in the respective PFU documents. In case you need help finding a good feeding strategy, do not hesitate to contact us. Spent media analytics can also help to understand and optimize your process. If you require support for analysis of spent medium samples, please contact our analytics team.

I have rehydrated my Xell powder medium and the colour looks different than described. What shall I do?

If you followed all the steps described in the solubilization protocol, please let the medium sit overnight after filtration. In some media, a reversible iron complex can be formed after the addition of the ESK supplement. Depending on the production process and storage, this will dissolve after 24 hours at the latest (but usually much faster).

Analytical Services

If you have any questions regarding our analytical services, the sample preparation and shipment you can find answers to the most common questions here. If you need further assistance we are always here to help – just contact us.

What is the sample amount needed for your analytical services?

Usually a sample amount of 1 mg (if purity is > 80%) or 1 ml is needed for each analytical service. If you are limited in your sample amount please contact us. We are open to discuss smaller volumes. If you send frozen samples for more than one analysis, it would be desirable to ship them in aliquots, to prevent repeated freezing and thawing.

What matrices do you analyse?

All of our analyses can be applied to spent culture media. The majority of our analyses can be also applied to food samples, animal feed samples and other feasible matrices, just contact us to find out more or discuss your specific matrix!

How do I have to ship my samples?

Please prepare your samples as stated on our Sample Preparation Protocol or discussed with us (for other than spent media samples). Please ship them together with our Sample Declaration Sheet. You can find the Sample Preparation Protocol and Sample Declaration Sheet here.

How do I have to prepare my samples?

Please prepare your samples according to our Sample Preparation Protocol or as discussed with us. Find the Sample Preparation Protocol here.

How will I receive my results of the analysis?

We will provide you with a short written report and, on request, as well with a table of results.

What is the method and LOQ for amino acid analysis?

For the amino acid analysis samples are analysed via UHPLC-DAD. The average LOQ is <0.03 mM, dependent on the amino acid and the sample matrix.

What is the method and LOQ for ion analysis?

For the ion analysis the samples are analysed via ICP-MS. The average LOQs can be found below. Please note that the LOQs can be matrix dependent.

Ion LOQ [mmol/L]
Sodium <50
Potassium <1
Phosphate 0.11
Calcium 0.01
Manganese 0.01

 

What is the method and LOQ for water-soluble vitamin analysis?

For the analysis of water-soluble vitamins the samples are analysed via UHPLC-MS/MS. The average LOQs can be found in the table below. Please note that the LOQs are strongly matrix dependent.

Vitamin LOQ [mg/L]
Thiamine (Vitamin B1) <0.007
Riboflavin (Vitamin B2) <0.0009
Nicotinamide (Vitamin B3) <0.029
(Calcium) Pantothenate (Vitamin B5) <0.003
Pyridoxal and Pyridoxine (Vitamin B6) <0.008
Biotin (Vitamin B7) <0.0015
Folic acid and aminobenzoic acid (Vitamin B9) <0.0065 resp. 0.0045
Cyanocobalamin (Vitamin B12) <0.003
Choline chloride (Vitaminoids) <0.068

 

What is the method and LOQ for trace element analysis?

For the trace element analysis the samples are analysed via ICP-MS. The average LOQs can be found in the table below. Please note that the LOQs can be matrix dependent. Further elements can be analysed on request!

Element LOQ [µg/L]
Chromium (Cr) 0.1
Manganese (Mn) 0.5
Iron (Fe) 1.0
Cobalt (Co) 0.2
Nickel (Ni) 0.5
Copper (Cu) 0.5
Zinc (Zn) 5.0
Selenium (Se) 1.0
Molybdenum (Mo) 0.2
Cadmium (Cd) 0.1

 

What is the method and LOQ for polyamine analysis?

For the polyamine analysis the samples are analysed via UHPLC-MS/MS. The average LOQs can be found below. Please note that the LOQs can be matrix dependent.

Polyamine LOQ [mg/L]
Putrescine <0.033
Spermine <0.1
Spermidine <0.033

 

Shipment and Storage

Here you find the most common questions regarding the shipment and storage of our cell culture media and feeds. If you do not find what you are looking for justcontact us for more information.

The media have been transported without cooling; can I still use them?

As long as shipping takes only a few days, the media can be sent by express without cooling. They normally arrive at their destination within approx. 48 h. Storage should then be realised at temperatures between 2°C and 8°C at a dark and dry place. For our stability studies we exposed the media to high temperatures (short term and long term) and they showed that a short time span in which the media are not cooled is not critical.

How are the media/feeds transported?

As long as shipping takes only a few days, the media can be sent by express without cooling so they normally arrive at their destination within 24 h – 48 h. Storage should then be realised at temperatures between 2°C and 8°C at a dark and dry place. For longer distances we either use styrofoam boxes and ice packs or for larger amounts of medium we ship pallets using a cooled transport.

Do the media/feeds have to be frozen?

No, the media/feeds should never be frozen! If the medium/feed was frozen we recommend to discard them.

How should I store the media/feeds?

All our media and feeds should be stored refrigerated, in a temperature range from +2° to +8° in a dark (!) and dry place. In our experience, frequently performed pre-heating of medium, e.g. before passaging is not necessary for most cells and processes and should be avoided if possible.