Technical library - RESOURCES

This method produces large numbers of adherent monocytes in only 1.5 h. If the washing steps are properly performed, 80-90% purity can be expected. The attached cells are “untouched”, since no binding of magnetic microbeads has occurred. This also excludes phagocytosis of the microbeads by the monocytes, an event which is unfavorable with regard to cellular health. In addition, the adherence method is time-saving and cost-effective.

Several different methods for the detection of mycoplasmas have been described, like e.g., cultures on agar, in liquid or semi-solid media, staining with DAPI, mycoplasma-specific antibodies, biochemical methods, and PCR-based assays. PCR-based detection is very sensitive, detects all mycoplasma species that occur in cell cultures and is completed within 3-5 hours.

No, mycoplasma can only be observed through electron microscopy. For highly sensitive detection of mycoplasma contamination, we recommend the use of PCR-based mycoplasma tests.

We use a classification system similar but not identical to the Fitzpatrick Skin Classification. The Fitzpatrick classification has six different categories (phototypes I-VI) which correlate with the level of skin pigmentation (melanin) and sunburn following sun exposure. Fitzpatrick I corresponds with the lightest of skin complexions, while Fitzpatrick VI corresponds with the darkest skin.

I: Pale white skin, blue/hazel eyes, blond/red hair, always burns, does not tan
II: Fair skin, blue eyes, burns easily, tans poorly
III: Darker white skin, tans after initial burn
IV: Light brown skin, burns minimally, tans easily
V: Brown skin, rarely burns, tans darkly easily
VI: Dark brown or black skin, never burns, always tans darkly

At PromoCell, we have knowledge of the patients’ skin color (white, brown or black skin), color of eyes and hair, but we don't have any details about the burning/tanning abilities. We therefore classify our tissue donors as follows:

Light (comprising phototypes I and II)
Moderate (comprising phototypes III and IV)
Dark (comprising phototypes V and VI)

Information on the phototype is available for most cell lots isolated from juvenile or adult skin.

a) We usually perform macrophage differentiation in T75 flasks and 6-well plates. We haven't tested differentiation in smaller formats. But we assume it will be problematic to thoroughly wash the surface of the wells to remove non-adherent cells after the attachment phase. b) Detachment of the mature macrophages is possible but re-attachment can lead to significant cell loss (30-50%). Please also keep in mind that working in 96/384 well-format has some inherent drawbacks (e.g., evaporation of media, dry wells, etc.).

You should use complete DC Generation Medium/DC Generation Medium XF (with all the cytokines). As cells are metabolically active, media should be changed every 3 days. We have observed that the dendritic cell phenotype remains stable for up to 7 days.

The Macrophage Detachment Solution (C-41330) directly affects the cell membrane. HSA in the Wash Buffer supports regeneration of the cell membrane and protects the cells during the critical phase directly after detachment from detrimental effects.

Our HDMEC pre-screened cells are isolated from juvenile foreskin.

Our human pulmonary microvascular endothelial cells (C-12281) are sourced from the lung parenchyma with all large vessels being removed beforehand. Therefore, most of the HPMEC originate from capillaries.

There are two options for isolating RNA from cells stored in RNAlater Solution: 1) The solution is removed from the cells prior to extraction by centrifugation at 5,000 x g for 10 minutes at 4°C. Note: Because of the density of RNAlater® solution, greater centrifugal forces are required to spin down the cells. 2) If no pellet is visible after centrifugation, RNA can also be purified directly from the RNAlater® solution. This can be done by adding 2 ml of 10x lysis buffer, and proceeding normally.

For chrondrogenic differentiation it is important that the cells do not adhere to the wells. During differentiation, the cells form spheroids which float in the medium. Therefore, there are no special requirements for the wells as long as they are U bottom shaped and suitable for suspension culture.

We have tested the differentiation capacity of our hMSC into adipocytes, chondrocytes and osteoblasts over time and still see good differentiation rates after 10 population doublings, i.e., at passage 5. However, the differentiation potential declines with ongoing population doublings. To obtain optimal differentiation rates, experiments should be performed as early in culture as possible.