Technical Library

Recent Entries in Technical Library

• For which cytokeratin are the keratinocytes tested?

  PromoCell is using a pan-cytokeratin antibody rather than a specific type of cytokeratin for the quality control of our keratinocytes.

  Related Links and Documents

  • Normal Human Epidermal Keratinocytes
  • Normal Human Epidermal Keratinocytes GM3
• Why is the actual cell count in the vial at PromoCell sometimes significantly higher than the 500,000 cells stated on the website?

  We guarantee > 500,000 viable cells per vial. To do this, we need to freeze more than 500,000 cells, as we do not yet know the viability after thawing at the time of freezing.
  For technical/organizational reasons, the initial cell number may also vary from lot to lot, so 2 lots with the same viability may not necessarily contain the same number of cells.

  Related Links and Documents

  • Human primary cell culture
• Can your Macrophage Detachment Solution also be used for bone marrow-derived macrophages from mice?

  Yes, there is a reference (Campuzano et al.; J Immunol. 2020 Jun 15;204(12):3296) where bone marrow-derived macrophages from mouse were detached using our Macrophage Detachment Solution (40 minutes at 4°C).

   

  Related Links and Documents

  • Macrophage Detachment Solution
  • Campuzano et al.; J Immunol . 2020 Jun 15;204(12):3296
• Are your NHEK from the epidermis of the juvenile foreskin mucosal or cutaneous keratinocytes or a mixed population?

  PromoCell’s Normal Human Epidermal Keratinocytes (NHEK) from juvenile donors are isolated from both the epidermis of the outer and mucosal (i.e. inner) layers of the foreskin. Thus, each vial contains a mixture of mucosal and cutaneous keratinocytes.

   

   

  Related Links and Documents

  • NHEK
  • NHEK in GM3
• Why is PBS added in the last step of the Alizarin Red staining protocol (“Osteogenic differentiation and analysis of MSC”)? Should the PBS be aspirated before analysis?

  The PBS buffering enhances the Alizarin Red staining (precipitation of the dye) and makes it more intense.
  Leave the PBS on the cells after staining/washing and analyze the sample immediately, as the dye may bleed upon prolonged storage without embedding.

   

  Related Links and Documents

  • Application Note: Osteogenic Differentiation and Analysis of MSC
• What are the disadvantages of the prophylactic use of antibiotics in cell culture?

  The use of antibiotics creates a false sense of security and allows users to develop poor aseptic techniques. This leads to low-level contamination with partially resistant bacteria occurring but being overlooked for a time. This then leads to cells with undetected contamination being cultured for extended periods of time, increasing the risk that contamination will spread throughout the laboratory and eventually antibiotic-resistant strains of bacteria may develop.
  Mycoplasma infections can also occur more easily, as they are often introduced along with contaminants such as bacteria and fungi.
  Last but not least, antibiotics are known to have negative effects on the metabolism of eukaryotic cells – more details on this topic can be found in our blog article “Antibiotics in cell culture: friend or enemy”.

  Related Links and Documents

  • Blog article: Antibiotics in Cell Culture: Friend or Enemy?
• I have accidently stored the Cryo-SFM at -20°C. Can the product still be used in this case?

  According to the product manual, Cryo-SFM should be stored at 4-8°C. However, since this solution is used to freeze cells in liquid nitrogen, we assume that storing Cryo-SFM once at -20°C should not have a negative impact on the product quality. After thawing, please store it at 4-8°C as recommended.

  Related Links and Documents

  • Freezing Medium Cryo-SFM
• How can I avoid precipitates when preparing my Mesenchymal Stem Cell Adipogenic Differentiation Medium 2?

  The supplement should be at room temperature when added to the MSC Adipogenic Basal Medium 2. It may also be beneficial to invert the tube a few times to bring precipitates back into solution.

  Please note: It is not recommended to filter the basal medium, supplements, or complete medium, as components that induce or promote differentiation may be removed, resulting in a low differentiation rate when using the medium.

  Related Links and Documents

  • Mesenchymal Stem Cell Adipogenic Differentiation Medium 2
• Are there any differences in the cultivation protocol when cultivating MSCs compared to other cell types?

  Yes, there are a few differences:
  – We recommend replacing the MSC Growth Medium XF (C-28019) 3-4 h after seeding, as opposed to 16-24 hours after seeding for most other cell types/growth media.
  – When MSC Growth Medium XF, MSC Neurogenic Differentiation Medium, MSC Adipogenic Differentiation Medium 2 or MSC Osteogenic Differentiation Medium are used, flasks have to be coated with 10 µg/cm² (human or bovine) fibronectin according to the instruction manual.
  – We strongly recommend using Accutase (C-41310) for cell detachment instead of Trypsin. If Trypsin is used, contact time should not exceed 2 min.

   

  Related Links and Documents

  • Mesenchymal Stem Cell Culture
• After thawing the supplements, I see some precipitation. Is this normal?

  Light flocculation may be seen upon thawing the supplements containing ECGS/heparin or BPE. This does not affect the activity of our media.
  Optionally, the precipitate can be removed by centrifugation under sterile conditions.

  We recommend to thaw the supplements (SupplementMix or SupplementPack) at 15-25°C.