Technical library

Yes. PromoCell Keratinocyte Growth Medium 2 (C-20011) can be used to culture primary mouse keratinocytes, provided that the calcium concentration is adjusted.
 
Calcium requirements

• For primary mouse keratinocytes, the CaCl₂ concentration should be reduced to 0.025-0.05 mM.
• By comparison, the optimal calcium concentration for primary human keratinocytes is 0.06 mM.

Keratinocyte Growth Medium 2 is supplied with CaCl₂ in a separate tube, allowing the calcium concentration to be easily adjusted to meet the requirements of various keratinocyte culture systems. 

In general, PromoCell does not recommend a specific plasticware.
However, for macrophage differentiation, the choice of plasticware can significantly influence experimental outcomes.
 
PromoCell experience
When using PromoCell Dendritic Cell and Macrophage Generation Media, we have observed that the surface properties of the cultureware can strongly affect:

• Detachment efficiency (differences of up to ~20%)
• Differentiation efficiency itself

Recommendation for M1/M2 macrophage differentiation
For M1-/M2-Macrophage Generation Media XF, PromoCell recommends Nunc™ plasticware with a Nunclon™ surface, as this surface provides more consistent results with respect to cell attachment, differentiation performance, and detachment behavior.

PromoCell does not generally recommend a specific manufacturer or brand of tissue culture plastic for the cultivation of its primary human cells.
 
What we know from experience
Our customers have successfully used tissue‑culture flasks and dishes from all major, well‑established cell culture plastic suppliers to grow PromoCell primary cells. We do not have sufficient data to assess whether plasticware from local or lesser‑known suppliers performs equivalently.
 
Our recommendation
If you plan to use tissue culture plastic from a supplier other than the established manufacturers, we recommend:

• Testing the plasticware first, and
• Confirming that it provides comparable cell attachment, growth, and morphology before using it in critical experiments.

Yes. This is completely normal.
PromoCell cell pellets (C‑14***) are supplied in RNAlater^TM, and these samples do not freeze at -20°C. They remain liquid at both 4°C and -20°C.
 
Storage stability of RNAlater^TM samples 

• Room temperature: stable for up to 1 week
• 4°C: stable for up to 1 month
• -20°C: can be stored indefinitely, even though the sample remains liquid

The liquid state at -20°C does not indicate a problem with sample integrity or stability.

Yes. PromoCell Normal Human Cells can be transfected. However, it is important to note that primary and normal human cells are generally much more difficult to transfect than immortalized cell lines. Transfection efficiency can vary widely and depends on multiple factors, including:

• Cell type
• Age/passage number of the culture
• Cell density at the time of transfection
• Transfection method used
• Purity and quality of the nucleic acids
• Composition of the transfection medium
• Overall experimental conditions

For optimal results, transfection parameters usually need to be carefully optimized for each specific cell type and application.

Precoating culture vessels with extracellular matrix (ECM) proteins does not have adverse effects on Human Umbilical Vein Endothelial Cells (HUVEC).
However, ECM coatings such as fibronectin, collagen, or gelatin have been reported to influence cellular gene and protein expression patterns.

Recommendation
To ensure reliable and comparable results, we strongly recommend using the same culture conditions throughout an entire experimental series, including:

• the same ECM coating (e.g. fibronectin, collagen, or gelatin), or
• consistently uncoated culture vessels

Maintaining consistent conditions helps minimize variability and improves the comparability of experimental outcomes.

PromoCell generally cultures human osteoblasts (HOB) on uncoated tissue culture‑treated plastic. However, osteoblasts can also be cultured on extracellular matrix–coated surfaces, such as type I collagen or fibronectin.
 
Important experimental consideration
Please note that the type of extracellular matrix (ECM) coating can influence:

• the expression of certain genes (e.g. integrins), and
• downstream cellular metabolism and function

Because of this, PromoCell recommends:

• Using the same coating matrix consistently across a complete set of experiments
• Avoiding changes in surface coating within a study to ensure comparability and reproducibility

No. PromoCell normal human epidermal keratinocytes (NHEK) do not require feeder cells when cultured in:

• Keratinocyte Growth Medium 2 (C‑20011), or
• Keratinocyte Growth Medium 3 (C‑20021).

Under these conditions, the keratinocytes grow as a monolayer in standard tissue‑culture‑treated flasks or dishes, without the need for any feeder layer.

PromoCell guarantees more than 15 population doublings (PDs) for its HUVECs.
The number of passages that can be performed depends on the split (dilution) ratio used during subculture:

• With a 1:4 split ratio, HUVECs typically achieve ~2 population doublings per passage
• Under these conditions, HUVECs can usually be cultured for at least 6–8 passages

Please note that passage number alone is not a fixed parameter, as it varies with the chosen split ratio and culture conditions. Population doublings are the more accurate measure of cellular age.

Yes. Pre‑coated culture vessels are required when culturing human mesenchymal stem cells (hMSCs) in PromoCell Mesenchymal Stem Cell Growth Medium XF (C‑28019).

Reason
MSC Growth Medium XF is a xeno‑free culture system that contains all necessary growth factors and supplements, but does not include attachment or spreading factors. Therefore, cells require an external coating to ensure proper adhesion.

Recommended coatings
Culture vessels must be pre‑coated according to the manufacturer’s instructions using one of the following options:
- Human fibronectin: 1 µg/cm²
- Human vitronectin: 0.5 µg/cm²
Alternatively, bovine fibronectin may also be used.