Frequently Asked Questions (FAQs)
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We offer high-quality cell lines including human cells, animal cell lines, fluorescence-tagged cell lines, iPSC lines, as well as different human primary cells (human mesenchymal stem cells, fibroblasts, follicular dendritic cells, HUVEC, oral cells).
In addition, you can acquire more than 30 different serum-containing media and 10 serum-free media for the cultivation and maintenance of various cell types.
Our service includes viral testing, mycoplasma detection service, cell line authentication, cell banking and species identification. Moreover, we offer bulk and custom manufacturing.
If available, you will find the references with the respective product.
Multiply the average cell count from each of the hemocytometer's 16 corner squares by 10,000. Final viability counts per milliliter of sample are obtained by multiplying the initial count by 5, to account for the 1:5 dilution caused by the addition of trypan blue. Example:
- (50 + 40 + 45 +52) ÷ 4 = 46.75
- 75 x 10,000 (10^4) = 467,500
- 467,500 x 5 = 2,337,500 live cells/mL in original cell suspension
- Alternatively use an automated cell counting device such as the CellDrop from DeNovix or the NucleoCounter NC-200 from Chemometec.
We strongly recommend to store the cells after receipt on dry ice for a very short time (1 day at the most) at -80°C and start culturing as soon as possible. If immediate culturing is not possible, the cryovial(s) must be stored at temperatures below -150°C. The quality of the permanent cell lines should be controlled within 60 days after receipt. Approach:
- Thaw the cells
- Determine cell viability
- Culture the cells
- Make up your own master stock.
All media available in our shop must be stored at 4 °C in the refrigerator. The supplements available have different storage conditions. Please refer to the information on the data sheets supplied.
- Bring water to a temperature of 37 °C in a beaker.
- Remove a vial of cells from liquid nitrogen storage with care, making sure to shield your hands and eyes.
- Loosen the vial's cap for 10 seconds to allow any liquid nitrogen to escape the threads, and then re-tighten the top.
- To thaw, just submerge the vial's lower half in the 37 °C water for four minutes.
- Wipe the outside of the vial with disinfectant solution and place it in a laminar flow culture hood of Class II, type A, once the contents have thawed until just a little piece of ice remains.
- To disperse the cells, open the vial and pipette the suspension up and down with a 1 mL pipette.
- Take out 20 µl, then add 20 µl of trypan blue solution to the cell suspension (e.g., Cat. No. 15250-061).
- Use a hemocytometer or an automatized cell count system to calculate the number of viable cells per milliter.
- Dilute the vial's contents (1 mL) to the concentration suggested in the product instructions.
- After inoculation, agitate the medium in the flasks to disperse the cells. Numerous cell types adhere rapidly to culture surfaces; If the medium is not evenly distributed immediately after inoculation, the cells may grow in an uneven pattern.
- Maintain the cultures in a cell culture incubator at 37 degrees Celsius with 5% carbon dioxide and 95% air humidity. Ideally, the culture should be left alone for at least 24 hours after it has been started.
The information on the cell culture medium we do recommend for a specific cell line is given on the product page for the cell line as well as in the product information. The most common cell culture media are available as basic as well as ready-to-use (containing e.g., FBS and other supplements) formulations.
Some cell lines such as NFS-60 or TF-1 need special ingredients in their culture medium. Our Conditioned media are a good supply of these factors.
In order to cryopreserve the cells in liquid nitrogen, we recommend to use either CM-1, which contains serum, or the serum free freeze medium CM-ACF.
Our product range also includes living cell cultures. Depending on the cell type, these are adherent or suspended cells.
After thawing and plating cryopreserved cells, the first medium change should be performed after 24 hours or overnight to remove any remaining DMSO and dead cells. The medium should then be replaced every 24-48 hours until the cells are ready to be passed. Protocols for each cell line contain more specific instructions.
Our cryopreserved cell lines or growing cultures may be expanded and cryopreserved again. However, the process of cryopreservation may alter the growth performance of cells.
We do not advise spinning cells out of cryopreservation medium before plating. When centrifugation is performed at too high speeds, it might cause damage to cells. In our cell culture labs, we have found that at low concentrations, DMSO is safe for the cells. We advise diluting the cells in culture medium until the final DMSO content is less than 0.4% (v/v).
For the most of our cells you do not need a special surface matrix for 2D culture. Only our induced pluripotent stem cells (hiPSCs) require a culture surface substrate that maintains pluripotency. Here we recommend to use iMatrix or Matrigel.
For the detachment of most of the cells provided by CLS (except for e.g., for some keratinocyte cells such as HaCaT), we recommend to use Accutase which gently detaches the cells from the bottom of the cell culture flask. Accutase works with most cell lines. In case of the need of alternative detachment solutions, these are indicated in the specific product information of the cell line.
When cells are separated from a tissue to generate a primary culture, a confluent monolayer or dense cell suspension is formed due to the cells' ability to proliferate in vitro.
In accordance with the traditional concept, a cell line is created after the initial collection and subculturing of this population (Freshney, R.I. (1987). Methods used to grow new tissues from animal cells. (New York: Alan R. Liss, Inc.) A primer on the fundamentals. Over the course of a cell line's existence, those cells with the greatest growth potential will prevail, leading to some genetic and behavioral homogeneity.
With this terminology, a population of cells that has undergone a genetic alteration that allows for infinite growth is called a continuous cell line. Constant cell lines are usually aneuploid. Even while it is possible to culture continuous cell lines through a large number of subcultures, there is a risk that additional genotypic and, by extension, phenotypic changes will occur at these very high passage numbers. One can achieve immortality in a variety of ways, including naturally or with the help of viruses or chemicals. Understand that different research teams may use slightly different operational definitions of these concepts. Many researchers avoid calling a population a "cell line" until they can prove that it has undergone some sort of genetic mutation.
Positively selected from a culture, either by cloning or some other means, a small subset of cells is called a cell strain. Since its original parent lineage was established, most cell strains have experienced significant genetic modifications. Some subsets of cells may have become more tumorigenic than the original line, or the transfection process may have resulted in the creation of a new strain.
Cell types, which include keratinocytes and melanocytes, are collections of cells that have a common phenotype. That's why it's safe to say that every donor's keratinocytes are the same cell type.
Stem cells aid in the production of new cells in healthy tissues and may aid in the repair of injured or damaged tissues. They serve as the foundation for the distinct cell types that comprise each organ in the body. Stem cells are distinguished from other cells by their ability to self-renew, proliferate for an extended period of time, and, under specific conditions, differentiate into specialized cells with distinct functions (phenotypes), including but not limited to cardiac cells, liver cells, fat cells, bone cells, cartilage cells, nerve cells, and connective tissue cells. Multipotency is the capacity of cells to differentiate into a variety of other cell types. What scientists discover regarding the regulation of stem cell differentiation can serve as the foundation for the development of novel treatments for a variety of life-threatening diseases and injuries.
Somatic (adult, non-germline) cells that have been reverted to an embryonic stem cell-like state give rise to induced pluripotent cells. As with embryonic stem cells, iPS cells are pluripotent because they can differentiate into any cell in the body. The process of creating these cells, commonly referred to as "reprogramming," involves the introduction of three to four genes for transcription factors into a somatic cell via retroviruses.
Recent techniques have replaced and reduced the number of genes required for transformation, utilized alternative gene delivery methods, or sought to replace genes with chemical factors. Patients with diseases such as ALS, Parkinson's, or cardiovascular disease can have their cells induced to form iPS cells. When differentiated into more specialized cell types, iPS cells have multiple applications, including the development of assays for studying disease processes, screening drug candidates for safety and efficacy, and use in regenerative medicine.
The word "Xeno" derives from the Greek word "Xenos," which means "strange." Therefore, Xeno-free (or Xenogeneic-free) would mean free of "strange" components, or components from a "strange" species (where "strange" is relative to the native species you are working with). In terms of cell culture, this would indicate that human cell lines can be cultured with human-derived components (such as human serum), and it is considered xeno-free because there is no difference between species.
You can find the information about shelf life of our products in the material safety data sheets at the respective product as pdf-file under product information/downloads.
It is not recommended to store our cell culture media products under 4 °C. Regarding our supplement products please use the individual safety data sheets to get information’s about storing.
Coming from research we experienced the time-consuming procedure of purchasing cell lines first-hand and decided to streamline our ordering process by streamlining licensing fees and offering standardized supply agreements, enabling many commercial applications without having to go through a strenuous licensing process.
We ship products to all countries but will sometimes prefer to forward you to one of our distributors to ease the ordering and shipping process. Also, this allows you to pay in your national currencies, possibly voiding you from bothersome duties and taxes. Please contact us if no distributor is listed for your, we will do our best to handle shipping directly to you.
After having confirmed your order, we will send you an order confirmation including the expected delivery date via email.
Choose a product of your choice and add it to your personal shopping cart. To complete your order, you need to register and create an account.
If you receive a damaged item, please contact us via mail (firstname.lastname@example.org). We will send you a troubleshooting form which you need to fill in and send back to us. We will check the problem, get back to you as soon as possible, and may replace the product.
You can pay conveniently by invoice or easily by credit card or prepayment. Payment by invoice, international customers typically have a 30-day payment deadline while customers from Germany have 14 days.
Shipping costs depend on the country you are ordering from and will vary greatly due to the amount and kind of products ordered. Please have a look at our shipping cost section for more information.
All cell products except our living cell products are shipped on dry ice. Our living cell products are shipped either at room temperature or with heat packs to keep the culture warm. All serum-containing media are shipped at 4 °C with cooling packs. All non-serum media are shipped at room temperature.
For international shipping, you will get a tracking number that you can use to track your order. For national shipping, this is only possible on request. In this case, please contact us via email.
Yes. It is possible to get a discount by ordering larger quantities. Please send us a request via email and we will come back to you with a special offer as soon as possible.
Mycoplasma-specific PCR; the cell-based assay Plasmotest; DAPI fluorescence assay; STR analysis; Species-specific Real-Time PCR.
Mycoplasma are the smallest and most unusual prokaryotes (0.2 - 2 µm in diameter). CLS can analyze your cell lines for the presence of mycoplasma. Mycoplasma infection of cell lines can have extensive and frequently underappreciated impacts. These consist of:
- Changes in growth rate
- Induction of morphological modifications
- Chromosomal anomalies
- Altered cell metabolism
- Reduced survivability after thawing a frozen ampoule
- Transformation, apoptosis, cytokines, signal transmission, and free radical induction
- Activation of macrophage obstructing antigen presentation
In addition, Mycoplasma can interfere with the function of membrane receptors and invade host cells.
Rapid test: Please provide a minimum of 50 µl cell suspension containing 50.000 cells. The cell suspension can be shipped at ambient temperature.
Premium test: Please provide a minimum of 1 million cells in a suitable freeze medium to ensure a robust and healthy culture for the cultivation and subsequent testing of the cells. Please ship the samples on dry ice.
CLS offers both short-term and long-term testing for mycoplasma detection. In the former, the samples are tested immediately after arrival whereas in the latter cell culture is initiated and the cells are tested after 14 days of antibiotic-free cultivation. Mycoplasma testing is performed using a two-point detection system with both the PlasmoTest™ - Mycoplasma Detection Kit (Invivogen) and the Certus QC – mycoADVANCED detection kit (Certus).
This test is a cell-based colorimetric assay. In the presence of mycoplasma, a reporter cell line induces a signaling cascade triggering a change of color in the medium from red to blue. The assay is performed in 96-well multiwell plates. Signals are detected in a microplate spectrophotometer at 620-655 nm. All mycoplasma and Acholeplasma species, but also other contaminants in cell culture such as bacteria, are detected.
Isothermal amplification is a fast and reliable test based on isothermal amplification of mycoplasma-specific DNA combined with real-time detection using a DNA-intercalating dye. The assay is capable of detecting six of the most common species that account for >95% of contaminations: M.orale, M.hyorhinis, M.arginini, M.fermentans, M.hominis, and A.laidlawii. Due to sequence homology, other mycoplasma species will be detected as well (M.pneumoniae, M.gallisepticum, and M.synoviae). To identify whether the sample is mycoplasma positive or negative, the melting temperature (Tm) is studied.
Viral detection of diseases such as HIV-1, HBV, and HCV is performed via the amplification of DNA or RNA and the detection of nucleic acids through probe hybridization.
Given the prevalence of cross-contamination and misidentification, the authenticity of cells employed in scientific research projects is a major concern. It is estimated that about 15-20% of all cell line-based research is working with misidentified cell lines. Therefore, determining a cell line's profile using STR analysis is crucial for carrying out reliable and repeatable research. Additionally, a growing number of journals demand cell line verification before accepting an article. We offer cell line authentication with a comparison with online databases and publication-ready analysis reports.
Please send us the samples in a padded envelope at room temperature. For gDNA please provide us with ≥ 50 μl of 50ng/μl gDNA in Tris or EDTA (10 mM Tris, 0.1 mM EDTA). For Cell Pellets, please provide us with 1.0 - 5.0 million cells as a cell pellet. Please wash twice with PBS and resuspend in 0.5 ml of 70-90% ethanol.
A DNA motif of 2-13 bases that is repeated up to several hundred times makes up a short tandem repeat (STR). Individual variability in the number of repetitions in an STR leads to variations in the length of the produced fragments when employing PCR. The cell lines are profiled using these variations in fragment lengths at several loci.
CLS offers cell banking services for your precious human or animal cells, derived from tissue or blood from patients or healthy individuals, or as an already established cell line. We will gently freeze and store your cellular material in the ultra-low temperature environment of liquid nitrogen (at approx. -190°C). Additionally, we can expand your cells in in vitro culture before the freezing process so that sufficient material is always available upon further request. On-demand, we will also thaw the cells again and provide you with fresh vital cells in culture.
Deep frozen cells are an ideal deposit for future application in basic research or for medical use and are a reasonable alternative for costly continuous cell culture. The application of cells starting from the frozen original material ensures the authentic genetic background whereas in long-term cell culture genetic shifts and possible cross-contaminations may occur.
We can also secure the identity of your original cells by genetic fingerprinting (STR analysis) and the absence of bacterial contamination, preferentially of Mycoplasma before the freezing process. Antibiotic treatment to erase Mycoplasma can be performed. Of course, your order and the storage will be handled confidentially and with the greatest care.
- Standardized price for the storage of up to 100 cryovials per month
- Gentle freezing process in liquid nitrogen
- Confidential storage
The purity of human and animal cell lines, which are being used all over the world in basic research, is a prerequisite for good results. A simple and reliable method to exclude cross-contaminations with other mammalian cells is Real-Time PCR.
The following species can be determined as a complete panel, parts of one panel, or as a single test:
- Homo sapiens (human)
- Mus musculus (mouse)
- Rattus norvegicus (rat)
- Chlorocebus aethiops (African green monkey)
- Canis lupus familiaris (dog)
- Bos Taurus (cattle)
- Sus scrofa (pig)
- Oryctolagus cuniculus (rabbit)
- Gallus gallus (chicken)
- Cricetulus griseus (Chinese hamster)
- Mesocricetus auratus (Syrian hamster)
Certificates of analysis for our products are available per request. Please contact us with the lot number of the product we have sent you. Just navigate to the section “Resources” on our website and fill in the information about the specific product.
You can find the material safety data sheets at the respective product as a pdf file under product information/downloads.
The product sheets are available in the download section of the product pages. Please, navigate to the product section and to the product of interest to obtain a product sheet. If you cannot find the product sheet in the download section, please get in contact with us to request the document.
The peak height ratio <25 % (to the highest peak within an STR) is mentioned in the summary table (comments). Peak height ratios <25% need not necessarily influence the behavior or characteristics of the cell line. A small peak height may be due to reduced amplification efficiency, for example resulting from a mutation in the primer site. The reason for the difference in peak heights observed, however, would need some in-depth analysis of the test item.
Non-coding STR regions are always composed of two alleles and are dispersed across the genome. The amount of repetitions within each allele defines the phenotypic profile of each individuum; hence, the existence of an extra profile in a given sample suggests sample contamination.