Normal Human Epidermal Melanocytes (NHEM)

Add to Wishlist

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.

Short protocol:

• Trypsinize the cells as usual
• Centrifuge and resuspend in suitable cold freezing medium at a density of 1-4 x 10⁶ cells/ml
• Cool down the cells slowly to -80°C (approx. -1°C per min). We recommend to use "Mr. Frosty" from Nalge or "CoolCell" from Biocision; which both provide gradual and controlled cooling rates when placed in a -80°C freezer overnight.
• Transfer the vials into liquid nitrogen for long-term storage

• Mesenchymal Stem Cells (C-12974/C-12971/C-12977) need Fibronectin-coating when grown in PromoCell MSC Growth Medium XF (C-28019) and when differentiated in MSC Neurogenic (C-28015); Adipogenic (C-28016); or Osteogenic (C-28013) Differentiation Media.
• Human monocyte-derived macrophages (C-12914/C-12916/C-12915/C-12917) must be seeded into Fibronectin-coated culture vessels in combination with PromoCell's M1- and M2-Generation Media XF (C-28055; C-28056).
• For efficient induction of osteoblast mineralization with PromoCell's Osteoblast Mineralization Medium (C-27020); the TC plates should be pre-coated with collagen type I.

• Liquid phase storage provides a consistent temperature of -196°C; a longer holding time and a greater vial capacity but involves the risk of contamination issues.
• Storage in the gas phase is very safe with respect to contaminations but the holding time of the cells is shorter and the vial capacity is reduced.

We guarantee 15 population doublings for our NHEM. In terms of passages this corresponds to approx. 6-8 subcultivations. 

We can however not guarantee that the activity of all melanocyte genes remains unchanged during this time. Primary cells do gradually change their phenotype in vitro. Therefore, it is recommended to use the cells for the important experiments at low passages.

After isolation and purification of our primary human melanocytes, the cells are checked during quality control whether they show a typical morphology and whether they express the marker Mel-5. Mel-5 is a 75 kDa glycoprotein usually expressed by normal melanocytes. Our Melanocyte Growth Medium (C-24010) has been developed to promote melanocyte growth in vitro. It does not however, completely block the growth of other cells (such as: NHEK or NHDF). 

Therefore, it is important to have a pure melanocyte culture from the very beginning. 

In contrast, the Melanocyte Growth Medium M3 (C-24310) is much more selective and represses the growth of contaminating cells much better.

The majority of our skin tissue donors are caucasians. But occasionally we also get skin biopsies from asian and black donors. 

Please contact our Scientific Support if you need cells from a particular phototype or origin. They will check our inventory and send you a list of available cell lots.

Yes, our NHEM.f will also grow in our optimized Melanocyte Growth Medium M3 (C-24310) and can achieve > 15 population doublings.