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 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 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 ∼25-65 years old.
- The visceral HWP donors are mostly between ∼20-75 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 Technical Customer 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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What is the number of primary cells per vial frozen at PromoCell? How can I calculate the number of viable cells and how should I calculate the optimal plating density?
At PromoCell we guarantee for our primary human cells ≥ 500,000 viable cells after thawing. For this, we dispense > 500,000 cells per cryovial before cryopreservation as there will always be a certain percentage of dead cells after freeze/thaw.
In order to know the number of cells that survived the procedure, we defrost a representative number of vials per lot during QC, determine the cell viability using an electronic counting device and then calculate the number of viable cells that can be recovered after thawing. Both numbers – the calculated number of viable cells and the viability – can be found on the lot-specific Certificate of Analysis (CoA) that can be downloaded from our website.
Example: When the CoA indicates 600,000 viable cells and a viability of 80%, this means that the vial actually contains 750,000 cells (viable + dead), 80% thereof (600,000) were viable after thawing in our QC. We do not indicate the total number of cells per vial but just the number of expected viable cells which can be recovered when the recommended thawing protocol is used. You don’t have to calculate any viabilities by yourself.
When the recommended plating density for your cell type is 5,000 – 10,000 cells/cm², then the 600,000 viable cells can be plated e.g. in a T75 (corresponding to 8,000 cells/cm²) or in a T75 + a T25 (corresponding to 6,000 cells/cm²).Related Links and Documents
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I am having problems isolating RNA from peripheral blood MNC pellets. Is there any reason you can think of why this would be?
Problems in obtaining RNA with good yield and purity from mononuclear cells (hMNCs) are quite common. The reason for this is the large amount of free genomic DNA usually contained in MNC preparations. This DNA originates mostly from granulocytes which underwent lysis during the isolation of the MNC. The granulocytes are gone in the final MNC preparation, but their genomic DNA – released during cellular lysis – is still there "sticking" to the MNCs. Solution: Remove DNA prior to RNA purification by a DNase digestion step. Most commercial systems include the option for such a DNase digest.
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What is the exact localization of PromoCell’s HRCEpC? Are the cells isolated from proximal or distal tubuli?
Our Human Renal Cortical Epithelial Cells (C-12660) are isolated from the cortex of the human kidney. The renal cortex is the outer portion of the kidney. It contains the renal corpuscles, the proximal and distal convoluted tubules, and the cortical collecting ducts.
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How does PromoCell determine the phototype of skin tissue donors?
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.
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When subculturing PromoCell’s proliferating HUVEC (T25 flask; C-12250), which TC flask should I use?
A subconfluent T25-flask typically contains between 0.9 and 1.2 million cells corresponding to 36,000-48,000 cells per cm2. It is recommended to count the existing cell number after trypsinization and to calculate the needed number of new flasks.
Recommended seeding density for HUVEC is 5,000-10,000 cells/cm2. This usually corresponds to a split ratio of 1:4-1:6. 1:6 means that you can increase the culture surface by factor 6 (e.g. from 1x T25 to 6x T25 or 2x T75).Related Links and Documents
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At what passage should I induce the differentiation of the SkMC?
For efficient differentiation of our SkMC into myotubes, we recommend to use cells that have undergone a maximum of 4-5 population doublings, i.e. not more than 1 additional subculturing step after thawing the original vial. For more details about differentiation, please see the instruction manual of our Skeletal Muscle Cell Media.
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Where can I find the composition of the supplements?
The qualitative and quantitative composition of the supplements can be found on our website and in the data sheets of the specialized media. When there is no such information specified, the composition of the supplements is confidential.
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From what part of the lungs does PromoCell isolate the human pulmonary fibroblasts (HPF)?
Our HPF (C-12360) are isolated from peripheral lung tissue.
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What is the difference between juvenile (C-12210) and adult HDMEC (C-12212)? Which ones should I use for my experiments?
Our juvenile HDMEC (C-12210) are isolated from foreskin of young male donors (1-10 years). In contrast, adult HDMEC (C-12212) are derived from different skin localisations like the cheek, temple, or breast. The donors are > 20 years old and are mostly female.
Adult HDMEC are the cells of choice when you need cells from a particular part of the body (other than foreskin), or if it is important for your study to use cells from female and/or adult donors.Related Links and Documents
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Is it necessary to use the PromoCell DetachKit when subculturing PromoCell Normal Human Cells?
We recommend to use the DetachKit when subculturing our Normal Human Cells. It contains a HepesBSS washing buffer, trypsin 0.04% / EDTA 0.03% solution, and TNS, a trypsin inhibitor from soybean.
Please note: Many of our culture media have low serum content or no serum at all. These media are not suitable to inactivate trypsin during subculture.Related Links and Documents
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I cannot find the Certificate of Analysis (CoA) pertaining to my cells. Can you please send me a copy?
The Certificates of Analysis can easily be downloaded from our PromoCell website:
https://www.promocell.com/certificate-of-analysis/
Simply type in the lot number indicated on the cryovial/TC-flask and click the SEARCH button.Related Links and Documents
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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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How does PromoCell recommend subculturing the chondrocytes (e.g. from T25 into T75 flasks, or into petri dishes)? Does PromoCell recommend a specific type or brand?
We recommend a seeding density for chondrocytes between 10,000 and 20,000 cells/cm². This means that a subconfluent T25-flask with approx. 900,000 cells/T25 flask (36,000 cells/cm² ) may be either split into 3 new T25 or seeded in one T75 flask or in one 100 mm petri dish. We do not recommend a specific type or brand for the culture of HCH.
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What culture conditions are required for culturing PromoCell Normal Human Cells in the respective PromoCell media?
PromoCell Normal Human Cells should be cultured in the appropriate medium at 37°C and 5% CO2 in a humidified atmosphere.
Please note: If using cell culture flasks w/o filter cap, unscrew the cap by half a turn to allow sufficient ventilation. -
Can you please provide me a protocol for the expansion of CD34+ Progenitor Cells in PromoCell Expansion Medium XF?
Short protocol:
- Thaw the cells (C-12921) for 2 min in a 37°C waterbath. Dilute in 9 ml of complete HPC Expansion Medium XF (+ Cytokine Mix E) and count the cells
- Spin down for 10 min at 240xg, aspirate the supernatant, resuspend the pellet at 20,000 cells/ml HPC Expansion Medium XF
- Plate in an appropriate suspension culture vessel and incubate the culture for 2-3 days at 37°C and 5% CO₂
- Then double the media volume by adding fresh complete medium, e.g., 4 ml suspension culture + 4 ml fresh medium (= 8 ml)
- Incubate the cells for an additional 10-12 days by performing a partial medium change every 2-3 days
Example partial medium change: For a culture volume of 8 ml, spin down the cells, aspirate and discard 4 ml of the supernatant, resuspend the cells and add 12 ml of fresh complete medium (= 16 ml).
In combination with the Cytokine Mix E, the HPC Expansion Medium XF typically promotes a 300-1,000 fold expansion of the total cell population. After 2 weeks of expansion about 20-30% of the population express CD34+, indicating a 50-200 fold expansion of CD34+ progenitor cells.
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Why does the macrophage differentiation in the PromoCell protocol take 10 days? In the literature or following the feedback from other researchers, it usually only takes 7 days.
M1 / M2 polarization also takes seven days in the PromoCell system but the protocol contains two more days for optional macrophage activation. If you only want non-activated M1 / M2 macrophages, the process is usually completed after 7 days.
Nevertheless, PromoCell does not recommend shortening the 10-day protocol because you actually get a plus in viability and cell yield (due to the re-attachment of floating cells) on day 8-10 due to the media change.Related Links and Documents
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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.
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We use Macrophage Generation Media from Promocell to get differentiated macrophages from fresh PBMC. Would it be okay if the attachment step with the Monocyte Attachment Medium is done overnight instead of 1.5 h?
We strongly advise against overnight incubation.
The Monocyte Attachment Medium does not contain cytokines/survival factors for the monocytes. If the cells remain in the Monocyte Attachment Medium for longer than 2 hours, they will go into apoptosis and die. The lymphocytes will survive longer. Some of them will attach after such a long time and then cannot be washed off.
Therefore, overnight attachment is absolutely inappropriate. However, if time is short, monocyte attachment can be shortened to 1 hour. To do this, it is best to add Monocyte Attachment Medium to the culture vessels in advance and equilibrate it in the incubator. Remove the vessels from the incubator only briefly to add the appropriate amount of concentrated PBMC suspension. Then, even after 1 hour, most of the monocytes are attached.
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Could you please let me know whether you have used the baculovirus expression system to produce components of your media?
Baculovirus is generally used in conjunction with insect cells (Sf-9, Sf-21) to produce recombinant proteins (cytokines, growth factors).
None of our Specialized Media (Media for Primary Human Cells; Blood and Stem Cell Media, Cancer Cell Media) contain recombinant proteins produced in insect cells. This also applies to our Cryo-SFM Freezing Medium. -
Do I need precoated flasks when growing my MSC in PromoCell Mesenchymal Stem Cell Growth Medium XF (C-28019)?
Our MSC Growth Medium XF (Ready-to-use) provides a xeno-free culture system for human MSCs. It contains all growth factors and supplements except attachment- and spreading factors. Therefore, culture vessels must be precoated with 10 μg/ml human or bovine fibronectin.
Protocol: Fibronectin coating
Dilute the Fibronection Solution to 10 μg/ml final concentration in Dulbecco´s PBS w/o Calcium and Magnesium. Overlay the culture surface of your tissue culture vessel with an amount of the diluted Fibronectin Solution sufficient to effectively coat the complete surface. Be sure that the entire surface is covered. Place flasks on a level surface at RT for 60 min. Aspirate the excess Fibronectin Solution and use immediately or let air-dry the open vessel under a laminar flow bench. Unused vessels may be stored at 4°C for up to 2 weeks.Related Links and Documents
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Is it normal that CD34+ progenitor cells attach to tissue culture plastic after a week-long culture in HPC Expansion Medium XF (C-28021)?
The cells sink down to the bottom of the culture vessel but don’t really attach. They retain a roundish morphology and can be rinsed off with culture medium easily.
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How should I handle PromoCell’s proliferating cells after arrival?
Short description:
Unpack the box and place the T25 flask(s) in the incubator for 3 hrs (closed cap). Then check confluency under the microscope.
When the density is < 70%, aspirate the medium using sterile conditions and add 5-10 ml of the appropriate Growth Medium. The cells should be subcultured according to the subcultivation protocol given in the cells’ Instruction Manual once they have reached > 70 % confluency.Related Links and Documents
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I have a question related to PromoCell’s CD34+ Progenitor Cells (C-12921). Are they suspension cells or do they partially attach?
It actually depends on the culture conditions whether the cells remain in suspension or attach to the surface.
When grown in our serum-free, xeno-free HPC Expansion Medium XF (C-28021), the cells remain in suspension.Related Links and Documents
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Can rat or mouse SkMCs be cultured using the Skeletal Muscle Cell Growth Medium (C-23060)?
Yes, the Skeletal Muscle Cell Growth Medium can also be used for rat, mouse and rabbit SkMC.
We recommend to use the medium right after isolation. Cells that were isolated and cultured in a different medium beforehand may have adapted to the other medium. An abrupt medium change causes stress to the cells resulting in reduced growth rates and lower differentiation capacities.Related Links and Documents
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Where can I find the composition of your basal media?
The formulation of our basal media is proprietary information. If you need to know the concentration of a particular component for your experiments, please contact the PromoCell Technical Customer Service.
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From which organism originate the recombinant cytokines in Cytokine Mix E (C-39890)?
All cytokines in Cytokine Mix E (human TPO, SCF, flt-3 ligand, and IL-3) are produced in E.coli. They are purified by chromatography, are free of endotoxins, and are tested for their biological activity.
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Are the PromoCell chondrocytes from orthopedic joint replacement surgery or other types of surgery?
Our chondrocytes are derived from patients (~55-80 years) who underwent surgery for total endoprothesis of the hip or knee joint. In most cases this is necessary due to arthrosis. If the tissue shows macroscopic lesions, it is not used for cell isolation.
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Will RNAlater solution denature the proteins in the cell pellets?
Yes, RNAlater Solution will denature proteins. Therefore, protein obtained from PromoCell cell pellets will be suitable for applications such as Western blotting or 2D gel electrophoresis, but not for applications that require native protein.
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Should I store the cryopreserved cells in the liquid phase or gas phase of liquid nitrogen?
In principle, both types of liquid nitrogen storage are acceptable, each having its advantages and disadvantages.
- 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.
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What is the approximate cell density of HFDPC (C-12071) at subconfluence?
Typical cell densities are between 32,000 – 40,000 cells/cm² (approx. 800,000 – 1 million cells per T25-flask).
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Are the HPAEC harvested directly from the pulmonary artery or are these microvascular endothelial cells?
Our HPAEC (C-12241) are harvested directly from the pulmonary artery. For their isolation, the vessel is explanted right after the position where the artery leaves the heart, including the bifurcation. HPAEC represent the innermost cell layer (i.e. the endothelial cells) of the pulmonary artery.
We also supply pulmonary microvascular endothelial cells (HPMEC; C-12281) isolated from the capillaries of peripheral lung tissue.Related Links and Documents
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How can I prevent fibroblast contamination in epithelial cell preparations?
Fibroblast contamination cannot be completely avoided in primary cell cultures. As epithelial cells attach more firmly than fibroblasts, it is possible to perform partial trypsinization to remove the fibroblasts. This is done by adding trypsin/EDTA to the TC dish for 2-4 min. When the fibroblasts detach, the enzyme is inactivated and the suspension with the fibroblasts aspirated. The remaining epithelial cells are washed twice with buffer and their culture is continued in the respective Growth Medium.
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Is it possible to refreeze the hCD34 progenitor cells after having amplifed them in PromoCell Hemaotopoietic Progenitor Cell Expansion Medium XF?
Yes, it is possible to refreeze them.
Related Links and Documents
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Is it possible to differentiate M1 macrophages from PBMC in 96-well plates?
At PromoCell, we have not tested macrophage differentiation from PBMC in 96-well plates, but we know from users that it is possible.
According to a customer the mononuclear cells differentiate very well in the 96-well format. A plating density of 1 million PBMCs (without prior determination of monocyte content) per well has been shown to be optimal. The working volume in a 96-well plate is usually 100 µl.
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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.
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Can PromoCell M1 macrophages be cultured after thawing in MEM alpha containing 10% FBS and GM-CSF?
We have never tested the cultivation of our assay-ready macrophages in MEM alpha + FBS. We cannot predict whether it will work and therefore strongly recommend the use of our M1 Macrophage Generation Medium XF and fibronectin-coated vessels.
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For how long can the monocyte-derived DCs be maintained in culture after the differentiation is completed (day 7/8 of the protocol)?
According to our experience, they can be maintained for 3 to a maximum of 7 days. However, the morphology will change and they will look more and more "degenerate".
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How big is the portion of MSC that can be differentiated into neuronal lineages?
Usually 90-100% of the hMSC show a neuronal morphology after differentiation with our Mesenchymal Stem Cell Neurogenic Differentiation Medium (C-28015). 60-80% of them are positive for nissl bodies after a nissl stain. However, the differentiation capacity depends on the origin of the cells and the number of population doublings they have undergone.
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What is the difference between PromoCell’s HREpC and HRCEpC?
Our HREpC (C-12665) comprise a heterogenous mixture of renal epithelial cells isolated from cortex and medulla. The HRCEpC (C-12660) are derived from renal cortex only.
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What are the different types of multiwell plates that can be used in fluorescence, luminescence and colorimetric detection? Which type should I use for which application?
1) For fluorescence detection (fluorometer): Black plates with clear bottoms; often clear plates will suffice 2) For luminescence detection (luminometer): White/opaque plates 3) For colorimetric detection (photometer): Clear plates
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Which of the PromoCell DetachKits, C-41200 or C-41202 should I use to trypsinize the HNEpC?
You can use our standard DetachKit (C-41200) to subculture the human nasal epithelial cells. Some customers still prefer to use our DetachKit-2 (C-41202) as it has a lower trypsin/EDTA concentration but tests in our cell culture lab haven’t revealed any adverse effects when using C-41200.
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From what muscles does PromoCell isolate the SkMC?
Our skeletal muscle cells are mainly isolated from M. pectoralis, sometimes also from M. gastrocnemius, M. intercostales or M. gluteus maximus.
The exact localization is specified in the Certificate of Analysis.Related Links and Documents
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