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Quick Cell Proliferation colorimetric Assay Kit Plus

based on 11 citations in multiple journalsQuick Cell Proliferation colorimetric Assay Kit Plus115 5
Sensitive, Non-radioactive Assay
Catalog #: K302
SKU-Size Size Price Qty
K302-500 500 assays
K302-2500 2500 assays
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Product Details

Detection Method Absorbance (420-480 nm)
Species Reactivity Mammalian
Applications The assay measures cell proliferation in response to growth factors/cytokines/mitogens/and nutrients etc.
Features & Benefits • Simple one-step procedure; takes less than 4 hours
• Convenient
• Uses a water-soluble tetrazolium salt WST reagent. The method is so simple that requires no washing/harvesting/or solubilization steps and is faster and more sensitive than MTT/XTT/or MTS-based assays. The entire assay can be performed directly in a 96-well plate.
Kit Components • WST Reagent (lyophilized)
• Electro Coupling Solution (ECS)
• Stop Solution
Storage Conditions -20°C
Shipping Conditions Gel Pack
USAGE For Research Use Only! Not For Use in Humans.


The Quick Cell Proliferation Assay Kit II provides by far the easiest and most sensitive means for quantifying cell proliferation and viability. The assay is based on the cleavage of the tetrazolium salt to formazan by cellular mitochondrial dehydrogenase. The amount of the dye generated by activity of dehydrogenase is directly proportional to the number of • Living cells. The formazan dye produced by viable cells can be quantified by multi-well spectrophotometer (microtiter plate reader) by measuring the absorbance of the dye solution at 440 nm. The assay can be used for measurement of cell proliferation in response to growth factors, cytokines, mitogens, and nutrients, etc. It can also be used for the analysis of cytotoxic compounds like anticancer drugs and many other toxic agents and pharmaceutical compounds. The new method is so simple, just add-and-read, requiring no washing, no harvesting, and no solubilization steps. It is faster, stable, and more sensitive than MTT, XTT, MTS based assays. The assay correlates well with the [3H]-thymidine incorporation assay.

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I see that it says the plate can be repeatedly read. Does this mean over the course of many days? I would like to compare the proliferation rates of 4 cell lines (wild type compared to stable cell lines expressing our gene of interest). I was wondering how best to do this using your kit. Can I plate out the cells and then continue to read the same wells every other day for two weeks? Or do I need to have wells for each time point?
No, the plate and the colour development cannot be read over a period of days. It is within the 4 hr incubation range, (or maybe slightly more than the 4 hrs if the desired OD is not achieved) after which the stop solution needs to be added. The plate can then be read within 48 hrs of stopping the colour development. In short, you need to have different wells for each time point. I would do the staining for all time points at the same time.
Hello, We are currently using a Quick cell proliferation assay kit II in our lab and I would like to know the minimum sensitivity (ie OD) the kit can detect. Below which OD value can we consider the reading as non-relevant (even if we substract an initial background)?
If I understand correctly, you are looking for an absolute cut-off value for the OD. This is a comparative assay, in which you can let the colour develop for an extended period of time to look at minor differences between various samples. The client will have to do their own statistical significance analysis on the differences they get form the use of this kit. They have to deem the control sample’s OD at 100% cellular proliferation or 0% cell toxicity and go from there in their comparative analysis.
My customer is using this kit to check the cell proliferation however they say the colour development does not stop even after 5 hours of incubation. Customer is asking what sort of data they could get from it and for how long the intensity will go higher and higher.
Yes, the color might develop with longer incubation of the samples. However, the machine can detect the absorbance only within a certain limit. Keeping that in mind, we recommend repeated reads and termination of the reaction by adding the stop buffer whenever the desired reading is achieved. The 0.5-4 hrs is just the expected time range within which this is expected to happen.
In the protocol Step 4, it says “incubate in standard culture conditions”. Is this 4C or RT
In step 4, standard conditions refers to the conditions in which cells grow, e.g. in an incubator at 37 degrees.
Is there any alternative buffer to dissolve the WST reagent (in case something happens to the ECS solution)?
Please dissolve WST reagent in ECS solution only. If something happens to ECS, consider buying more of just ECS.
Is the kit compatible with all media types? (DMEM, Serum Free, etc…)
Yes, it is compatible with all media types, as long as your control untreated cells also grow in the same media.
Can this kit be used for both adherent and floating cells?
Yes, it is compatible with adherent and suspension cells.
What does the stopping solution contain? Is it basic or acidic solution or the enzymatic stopping is based on something else than pH?
The stop solution is detergent based.
Is this reagent WST also based on mitochondrial dehydrogenase activity? Could you please confirm?
Yes, this kit is based on mitochondrial dehydrogenase activity.
I am very surprised that this reagent (ECS) is not very toxic. MTT is very toxic.
ECS reagent does not contain the toxic MTT.
Can this kit be used with samples like bacteria, plants, drosophila, yeast etc?
We have optimized the kit with mammalian samples. However, theoretically these kits should work with samples from multiple species/sources. Since the optimal conditions depend on the sample type, the protocol has to be be adapted to fit the samples for efficient results. Please refer to this kit's citations to see what kind of samples have been used with this kit other than mammalian samples.
Can we use frozen samples with this assay?
Fresh samples are always preferred over frozen samples. However, frozen samples can also be used, provided, they were frozen right after isolation, were not freeze thawed multiple time (for which we recommend aliquoting the samples before freezing) and have been frozen for relatively short periods.
What is the exact volume of sample required for this assay?
There is no specific volume we can recommend for the amount any sample to be used since it is completely sample concentration and quality based. You have to do a pilot expt with multiple sample volumes to determine the optimal volume which gives a reading within the linear range of the standard curve. Please refer to the citations for this product to see what other clients have used with similar sample types.
Do you have trial sizes of this kit?
Unfortunately, we do not have trial sizes of this kit available. However, if you are based in the US or Canada, we will give you a 10% off list price introductory discount on its purchase price. If you are based out of this area please contact yopur regional BioVision distributor.
What is the shelf life of this kit?
This kit is good for 12 months from the date of shipment in the unopened form when stored at the appropriate temperature and appropriate conditions. After opening and reconstitution, some of the components in this kit are good for 2 months at -20°C. Please refer to the datasheet for storage information and shelf life of each of the components.
Can we purchase individual components of this kit?
Yes, you can purchase any of the kit's components without the whole kit. Please refer to the component Cat #s mentioned on the datasheet for ordering.
Can we use an alternate buffer for sample preparation (cell lysis, sample dilutions etc)?
Our assay buffers are optimized for the reactions they are designed for. They not only contain some detergents for efficient lysis of your cells/tissue, but also contain some proprietary components required for the further reactions. Therefore, we highly recommend using the buffers provided in the kit for the best results.
My data shows huge variations. What could be the reason?
The rate of WST-1 cleavage may be affected by the availability of NADH, redox status of the cells and/or the presence of reactive oxygen species. If you see huge variability even after taking all the precautions it could be simply because of the cell type you are using. In that case, it is best to validate your results by using alternative techniques like LDH assay.
I see precipitates in my WST reagent. What should I do?
Incubation at 370C for 10 minutes followed by gentle agitation was always sufficient to resolve the problem
What are the potential interference?
Phenol Red will increase the absorbance by no more than 0.1 OD units; however, the negative controls make it possible to compensate for this. The addition of up to 10% FCS/FBS also causes no problems
What are the advantages of WST-1 compared to other cell proliferation agents?
WST-1 has multiple advantages:
1. Unlike MTT, WST-1 forms water soluble formazan crystals which can be measured without solubilization.
2. WST-1 is more stable compared to XTT and MTS. Thus it can be used as a ready to use solution, stored at 4°C without significant degradation.
3. WST-1 has a wider linear range and develops color faster compared to XTT.
Constanca Figueiredo, Low immunogenic endothelial cells endothelialize the Left Ventricular Assist Device. Sci Rep., Aug 2019;  31383930.
Sangmin Kim, et. al. Silibinin Suppresses EGFR Ligand-induced CD44 Expression through Inhibition of EGFR Activity in Breast Cancer Cells. Anticancer Res, Nov 2011; 31: 3767 - 3773.
Peng, H. et al. AC-SDKP inhibits transforming growth factor- 1-induced differentiation of human cardiac fibroblasts into myofibroblasts Am J Physiol Heart Circ Physiol, Feb 2010; 10.1152/ajpheart.00464.2009.
Paris, D. et al. Impaired Ortotopic Glioma Growth and Vascularization in Transgenic Mouse Models of Alzheimer's Disease. J. Neurosci., 2010; 30: 11251-11258.
Bao X et al (2009) PNAS; 106: 12109 - 12114.
For more citations of this product click here