Have a question about one of our products? Check out our technical library for recently asked questions from other scientists around the world.
Technical Library
Recent Entries in Technical Library
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What are the advantages of monocyte enrichment by adherence selection using your Monocyte Attachment Media (C-28051)?
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 occured. 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.
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Is it normal that the cell pellets from PromoCell (C-14**) do not freeze at -20°C?
Samples in RNAlater will NOT freeze at -20°C, they are liquid at 4°C and -20°C. The samples can be stored at 4°C for up to 1 month and are stable at room temperature for up to one week. At -20°C, they can be stored indefinitely.
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What’s the difference between NHEK.f and NHEK.f pooled?
NHEK.f are isolated from tissue samples (foreskin) of single donors, aged between 1-10 years. NHEK.f pooled are prepared from the foreskins of 3 individual donors. The cells of each donor are expanded in separate TC vessels and the cells are pooled after secondary culture, before cryopreservation.
Both NHEK from single donor and NHEK pooled are in P2 after thawing.Related Links and Documents
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Do the PromoCell keratinocytes need feeder cells?
If you are growing our NHEK in PromoCell Keratinocyte Growth Medium 2 (C-20011) or Growth Medium 3 (C-20021), you don’t need any feeder cells. The cells will grow as a monolayer in conventional tissue culture flasks.
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Why does PromoCell only guarantee 15 PDs when with my own self isolated dermal fibroblasts I regularly achieve 30 passages?
The PromoCell quality control procedure includes the cultivation of fibroblasts for 15 population doublings. This is to ensure that the cells can be grown for a minimum of 15 PDs (6-8 passages depending on the split ratio used) but it does not mean that the cells immediately senesce after that point. We don’t determine the maximum number of doublings or passages but most NHDF lots will certainly achieve > 20 passages.
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What is the reason for turbid serum?
Serum turbidity is usually caused by cryoprecipitation of lipid components during freezing and thawing. The more times the serum is subjected to freeze/thaw cycles, the more turbidity is noticed. It can be minimized by freezing the serum in aliquots at -20°C and thawing these aliquots individually at the time of use.
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Can I aliquot the SupplementMix?
Yes, you can aliquot the SupplementMix upon delivery and freeze down 2 or 4 individual aliquots at -20°C. This way, you can prepare smaller volumes (2 x 250 ml or 4 x 125 ml) of complete culture medium and thus extend the time you can use the medium.
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Why does PromoCell use CD146 as a marker for pericytes?
CD146 (MUC18) is a surface marker, expressed on pericytes, MSCs, and endothelial cells from large vessels (but not microvascular endothelial cells). In combination with CD34 (a marker for endothelial and hematopoietic cells), pericytes can be characterized by FACS analysis as CD146+/CD34–. The absence of CD34 expression makes sure that the cells are not of hematopoietic/endothelial origin. Further markers that have been described for pericytes are NG2, CD90, alpha-SMA, and PDGFR-beta.
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Are the HDMEC pre-screened (C-12215) derived from juvenile foreskin or from adult skin?
All HDMEC pre-screened lots that we currently have in stock are isolated from foreskin.
If you need pre-screened HDMEC from adult donors, please contact the PromoCell Technical Customer Support.Related Links and Documents
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Is it possible to perform experimental starvation with PromoCell Normal Human Cells and the PromoCell media?
Yes, but the experimental starvation conditions have to be determined individually for each cell type. Usually, the cells are maintained in basal medium with reduced growth factor concentrations or lower FBS content. The cells need to be in a good condition and the starvation should be kept as short as possible as prolonged serum and/or growth factor deprivation induces apoptosis.
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At what passage are PromoCell Normal Human Cells upon arrival?
The passage number varies depending on the cell type. Please refer to the Manual for your cells under “Specifications”.
You will also find the information in the Certificate of Analysis (CoA).Related Links and Documents
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My Normal Human Cells are growing slowly after subculture. What could be the reason?
Slow growth after subculture can be caused by over-trypsinization or other suboptimal culture conditions. Please see attached trouble shooting guide for possible reasons.
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How should I seed the preadipocytes for optimal differentiation?
Recommended procedure:
– Thaw the vial according to our protocol
– Seed one part of the cells (5,000 cells/cm²) directly into multiwell plates for subsequent differentiation induction; grow in Preadipocyte Growth Medium until they reach 100% confluency, then induce differentiation according to the recommended protocol
– Seed the other part (5,000 cells/cm²) into a TC dish and expand them in Preadipocyte Growth Medium; trypsinize at subconfluence; if necessary divide the cell suspension again into two parts and use one part for differentiation tests (see above), the other part to continue the culture of undifferentiated HWP.
– Differentiation capacity may decline after 1-2 passages in vitro, therefore best perform your differentiation tests at early passages. HWP at higher passages can still be used for studies that require undifferentiated HWP (e.g. proliferation assays).Related Links and Documents
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What happens if I grow CD34+ or CD133+ progenitors in Hematopoietic Progenitor Cell Expansion Medium XF (C-28021) without Cytokine Mix E (C-39890)?
The cells will die. Hematopoietic Progenitor Cell Expansion Medium XF always must be supplemented with Cytokine Mix E or an appropriate cocktail of cytokines.
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Why are the cryopreserved macrophages abbreviated as hMDM-GMCSF(-) and hMDM-MCSF(-), respectively? What does the (-) stand for?
- hMDM-GMCSF is the abbreviation for human monocyte-derived macrophages. They are polarized [⇒ differentiated with GM-CSF] but non-activated [⇒ (-)] M1 macrophages.
- hMDM-MCSF is the abbreviation for human monocyte-derived polarized [⇒ differentiated with M-CSF] but non-activated [⇒ (-)] M2 macrophages.
The macrophages can be seeded into all kinds of TC vessels. After plating, they can be maintained as biologically functional adherent cultures for several weeks.Optionally, user-customizable activation of the cells can be performed. For details, please see attached Application Note, page 2, Fig. 3 and page 5, Tab. 1).
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I differentiated M1 macrophages from self-sourced PBMCs following your differentiating protocol. In the final cell culture, I can see small cells attached to the macrophages which are CD3+ (T-cells). What is the reason for the T-cell contamination after the differentiation?
The reason for the higher number of lymphocytes in the macrophage culture is probably due to an insufficient washing step during the purification of the monocyte via adherence. The 3 washing steps in our protocol are essential to receive a monocyte population of over 90%.
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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.
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Is it possible to thaw and re-freeze the Cytokine Mix M1 (C-39894) and M2 (C-39895)?
The Cytokine Mix M1 and M2 should not be subjected to further freeze/thaw cycles.
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Can I cultivate the macrophages in complete medium but w/o cytokines?
Without cytokines, the macrophages will die very quickly. You must supplement the Macrophage Base Medium XF (Bsal Medium + SupplementMix) with the appropriate cytokines or at least with human AB ser
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We use Macrophage Generation Media from PromoCell to get differentiated macrophages from peripheral blood monocytes. The monocytes are isolated by culturing PBMCs in Monocyte Attachment Media (also from PromoCell) for 1.5 h. Would it be ok if the attachment step is done overnight, since we receive the blood later in the day which makes it difficult to process on the same day?
It is not recommended to leave the blood cells in the Monocyte Attachment Medium for longer than 1.5-2 hrs. The medium was developed for (short-term) attachment of the monocytes and does not provide nutrients for a longer time period. Leaving the cells in Monocyte Attachment Medium for a longer time or even overnight will induce apoptosis and lead to the loss of the cells.
If necessary, you can reduce the incubation time to 1 hr. In this case, it is advisable to equilibrate the media in the incubator before so that you can immediately and directly add the appropriate amount of PBMC suspension.Related Links and Documents
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Does PromoCell recommend a particular manufacturer or brand of tissue culture plastic to grow the primary cells or can I use any supplier on the market?
Our customers have successfully used TC flasks and dishes from all the leading cell culture plastic suppliers to grow PromoCell’s primary human cells. We do not have any knowledge whether the dishes from local TC plastic suppliers work in the same way. We recommend to first test whether these brands provide the same good performance as the plastic of the leading manufacturers.
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After differentiation of human MSC into mature adipocytes – what medium do I have to use to culture those cells?
Differentiation of hMSC into mature adipocytes takes approx. 2 weeks. You can keep the adipocytes for up to 3 weeks in the MSC Adipogenic Differentiation Medium. After 3 weeks we recommend to switch to PromoCell’s Adipocyte Nutrition Medium (C-27438).
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What is the composition of Melanocyte Growth Medium M2 SupplementMix (C-39420)?
Supplement Mix for Melanocyte Growth Medium M2 (C-39420) is free of serum and doesn’t contain any PMA. The qualitiative and quantitative composition is proprietary.
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What is the source of PromoCell’s Normal Human Follicle Dermal Papilla Cells? For how long can they be maintained in culture?
HFDPC are isolated from the hair papilla of normal human scalp hair follicles. Hair papilla in the adult hair follicle play a crucial role in the dermal-epidermal interactions that control hair production and in hair growth cycle events. The follicle dermal cells are cryopreserved at second passage and can be cultured for at least 10 population doublings when using PromoCell Follicle Dermal Papilla Cell Growth Medium (Cat. C-26501). Typical population doubling times are between 20-36 hrs.
The recommended seeding density after thawing/trypsinization is 5,000-10,000 cells/cm2. Using 1:4 splits, you can perform 4-5 passages with the cells.Related Links and Documents
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Do PromoCell HDMEC exhibit migration and tube formation as a response to angiogenic stimuli?
In principle, all microvascular endothelial cells should be able to migrate, proliferate and form tubes or sprouts in an appropriate assay after angiogenic stimulation. As this is not part of our routine quality control procedure, we cannot tell for sure whether all cell lots will respond to angiogenic stimuli. However PromoCell also supplies HDMEC pre-screened (C-12215) that are especially tested for a positive VEGF response.
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How should I store the PromoCell media and supplements?
Upon arrival, the basal media should be stored between 4°C and 8°C, the supplements at -20°C.
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How does PromoCell characterize their kidney cells (HREpC; HRCEpC) ?
Our kidney cells are characterized by their epithelial cell morphology and by cytokeratin expression using a pan-cytokeratin antibody.
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Which medium do PromoCell recommend to use on HUVEC – Endothelial Cell Growth Medium or Endothelial Cell Growth Medium 2?
The standard medium for isolation and propagation of our HUVEC, HUAEC, HPAEC, and HSaVEC is Endothelial Cell Growth Medium (C-22010). It contains ECGS, an extract from bovine hypothalamus which has mitogenic effects on endothelial cell proliferation. Scientists who prefer a more defined Growth Medium can use Endothelial Cell Growth Medium 2 (C-22011). In this medium, ECGS is replaced by VEGF, IGF, and additional bFGF and EGF to stimulate endothelial cell growth.
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Can I use my own trypsin or other commercially available trypsin solutions for subculturing PromoCell Normal Human Cells?
Most commercially available trypsin solutions have trypsin concentrations of 0.05% or higher which can harm the primary cells. PromoCell recommend using a 0.04% trypsin / 0.03 % EDTA solution for the subculture of Normal Human Cells.
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What plating density should I use for PromoCell Human Adult Stem and/or Blood Cells?
The recommended plating density after thawing/subculture may vary depending on the cell type. It is specified on the Website (tab: additional Information) and in the Product Manual.
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How can I test whether my cells are infected with mycoplasma?
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.
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Can PromoCell supply preadipocytes (subcutaneous, visceral) from donors with obese BMI / non-smokers / non diabetics? Can PromoCell supply preadipocytes from different age groups?
The basic information we receive from the surgeons about the tissue donors usually includes age, gender, and ethnicity.
- For many of our donors of subcutaneous preadipocytes, we also have information on BMI, hair color, skin pigmentation, and, in some cases, smoking habits or known diseases (e.g. Diabetes). Most of our subcutaneous HWP donors are between ∼20-65 years old.
- The visceral HWP donors are mostly between ∼20-85 years old. For many cell lots we know the BMI, in some cases also the hair color, skin pigmentation, smoking habits, and/or known diseases (e.g. Diabetes or COPD).
If you are looking for particular specifications, please contact our Scientific Support, so that we can offer you appropriate HWP lots.
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Which type of endothelial cell is best suited for studying angiogenesis?
The study of angiogenesis has been significantly advanced by the ability to culture endothelial cells in vitro. Initially, large vessel ECs, such as those isolated from the human umbilical vein (HUVEC) were used for these studies but increasingly it has been recognized that microvascular endothelial cells are a more appropriate model since angiogenesis involves microvessels rather than large vessel ECs.
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If I isolate fresh CD14-monocytes for M1/M2 macrophage generation, can I culture them for a period of time before differentiation?
This is not advised. Please seed the freshly isolated CD14-monocytes immediately in the Monocyte Attachment Medium. Adding a culturing step will change the biological characteristics of monocytes very rapidly.
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Can the medium for M2 macrophages be switched into RPMI or RPMI + M-CSF after differentiation?
Unfortunately, we did not test this in our hands, and it must be tested by the customer. In fact, our medium is completely different from RPMI and therefore we cannot predict if this is working. We only know the successful long-term culture from our system with our media.
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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, including MSC Growth Medium 2.
– 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
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Can I use a serum-free medium as negative control in the chondrogenic MSC differentiation? I would like to replace the recommended DMEM+10% FCS.
You could probably use our MSC Chondrogenic Differentiation Medium without inducers (C-28014). It is also serum-free and the same as C-28012, just without chondrogenic inducers.
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If I isolate tumor cells from my PDX animal model using your PCCS, will the animal cells survive?
In our Primary Cancer Culture System (PCCS, C-28081), only the malignant tumor cells can survive. Therefore, benign animal cells (e.g., fibroblasts) will be depleted and the malignant human tumor cells will survive.
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Is there is a difference in the percentage of differentiated DCs depending on whether we start with cryopreserved or fresh isolated monocytes?
There is no significant difference in the percentage of cells that will differentiate into Dendritic Cells. But when using cryopreserved cells, the initial cell loss will be higher compared to when fresh cells are used. i.e. the final number of differentiated cells that can be expected will be higher with fresh cells as a starting material due to lower cell death rate.
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Can PromoCell release the species the following cytokines were produced in: basic Fibroblast Growth Factor and Epidermial Growth Factor included in the Endothelial Cell Growth Media supplements?
Both cytokines are produced in E.coli.
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What is the differentiation ratio that can be achieved with PromoCell’s subcutaneous HWP?
Most of our subcutaneous preadipocyte lots achieve > 80-90% differentiation when differentiation is induced at P2 (directly after thawing).
We generally recommend using cells for differentiation tests that haven’t undergone more than 4-5 doublings (a maximum of 1 passage after thawing), as the differentiation ratio will decline with the age of the cells.Related Links and Documents
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The HDMEC I purchased from PromoCell seem to contain 2 different cell morphologies. How is this possible? What’s the purity of HDMEC cultures guaranteed by PromoCell?
Our HDMEC are isolated from the dermis of juvenile foreskin or adult skin. The purity is > 95%.
Since the dermis contains blood and lymphatic capillaries, HDMEC cultures comprise blood and lymphatic microvascular endothelial cells that have differing morphologies. Both cell types have a common origin and can be identified by several markers. The ratio of lymphatic and blood derived endothelial cells can vary from lot to lot and is not determined at PromoCell.Related Links and Documents
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What is the basis formula for PromoCell’s Osteoblast Basal Medium (C-27010)?
PromoCell’s Osteoblast Basal Medium is an optimized media formulation developed for human osteoblast culture. The exact composition is proprietary.
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Can I expand the human Mesenchymal Stem Cells prior to differentiating them?
These cells are frozen at the end of 2nd culture. Thawing and seeding results in passage 2 (3rd culture). We recommend that they be used for differentiation experiments not later than passage 5.
The differentiation potential of hMSC in vitro is reduced with ongoing population doublings, meaning the earlier differentiation is induced, the higher the differentiation rates.Related Links and Documents
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What is the lead time when ordering customized media from PromoCell?
The lead time is usually 4-8 weeks.
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Where in the lung are the HPMEC harvested from? Are the cells from arterioles or capillaries?
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.
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Do the PromoCell HCMEC represent the endocardial cells, i.e. those lining the ventricles? If so, why are they referred to as microvascular endothelial cells?
Our HCMEC (Human Cardiac Microvascular Endothelial Cells) are not endocardial cells. They are isolated from the capillaries in the heart muscle. Therefore, they are in fact microvascular.
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Can I use PBS instead of HepesBSS to wash the cells before trypsinization?
The PromoCell trypsin 0.04% / EDTA 0.03% solution and the PromoCell TNS solution are both based on HepesBSS. Therefore, it is best to also use HepesBSS to wash the cells prior to trypsinization.
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What plating density should I use for PromoCell Normal Human Cells?
The recommended plating density after thawing/subculture may vary depending on the cell type. Please refer to the data sheet for your cells under “Specifications”.
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How can I successfully isolate HUVEC from umbilical cords without using antibiotics?
At PromoCell, we get the umbilical cords from our tissue suppliers with no addition of buffers or media. This method prevents the microorganisms from being washed into the blood vessels. Before we start the cell preparation, the umbilical cord is also cut on both ends with a sterile scalpel to provide sterile intersections in addition to the sterile lumen.
This method allows us to isolate sterile endothelial cells from umbilical vein and to plate them in antibiotics-free culture media.Related Links and Documents
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