A cytotoxicity assay is a scientific test that measures the harmful effects of a substance (i.e. target drug candidates) or biomaterials on living cells. It’s used to evaluate the safety of drugs and the potential for a substance to cause cell death
In Vitro Cytotoxicity Assays are used to identify toxic effect of a new target drug candidate at early drug development stages before proceeding for further assays.
A cytotoxicity test used to determine the cytotoxic effect of new target drug candidate on live cells. These tests involve exposure of test drug to different cell lines at different concentrations and then checking the viable cells by using different protocols.
In vitro cytotoxicity test methods:
Trypan Blue Exclusion Assay:
Trypan blue exclusion assay is one of the basic cytotoxicity assays used to calculate the cell number and percentage of viable cells in a cell population using trypan blue dye. This dye is permeable for dead cells but impermeable for normal cells due to a damaged plasma membrane.
Propidium iodide uptake assay:
Propidium iodide (PI) staining is a technique that uses a fluorescent molecule PI to stain DNA in cells. Live cells and early apoptotic cells exclude PI due to intact membrane, but apoptotic cells stain with PI due to damaged plasma membrane.
MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay):
The MTT assay is defined as a colorimetric method that measures cellular metabolic activity by assessing the reduction of MTT to purple formazan crystals primarily by mitochondrial dehydrogenases, providing insights into cytotoxicity levels in cell lines and primary cell. Formazan is a water-insoluble dark-blue/purple product that’s created when the mitochondrial dehydrogenase enzyme in living cells reduces the yellow water-soluble MTT substrate. The amount of formazan formed is directly proportional to the number of viable cells.
Alamar Blue assay:
Alamar Blue is a direct indicator of cell health, it detects the level of oxidation during respiration, quantitatively measuring cell viability and cytotoxicity. Resazurin, a fluorescent red dye, reduced to resorufin after entering in living cells. Researchers widely use it to study cytotoxicity, proliferation, and metabolic activity within the cell.
Advantages of using in vitro cytotoxic assay
- Rapid: In vitro cytotoxicity assays are rapid.
- Inexpensive: In vitro cytotoxicity assays are inexpensive.
- Animal-free: In vitro cytotoxicity assays do not require the use of animals.
- High throughput: Researchers can use in vitro cytotoxicity assays to test a large number of drugs in one go.
Applications of in vitro Cytotoxicity Assay
In vitro cytotoxicity assessment is done before the in vivo animal test to assess the cell viability of new target drug candidates. This approach offers several advantages like reducing the need for animal testing, lowering costs, and speeding up the development and availability of these molecules.
Drug discovery
In vitro cytotoxicity assays are used to characterize the toxic potential of new target drug candidates.
Medical device evaluation
In vitro cytotoxicity assays are used to evaluate the toxicity of medical devices.
Cancer research
In vitro cytotoxicity assays are used to evaluate tumour cell growth inhibition.
Safety assessment
Determine safe exposure levels and identify potential health risks from chemicals in cosmetics, household products, and industrial compounds.
Environmental pollutants
Study the effects of environmental contaminants like heavy metals, pesticides, and industrial waste on cellular health.
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Conclusion
At Kosheeka, we are committed to provide high quality cells for cytotoxicity assay which are amenable to high-throughput drug screening. These cells undergo robust screening for viability and functionality.
Frequently Asked Questions (FAQs)
Q.1 What is in vitro cytotoxicity assay?
A cytotoxicity assay is a scientific test that measures the harmful effects of a substance or medical device on living cells. Researchers use it to evaluate the safety of products and the potential for a substance to cause cell death..
Q.2 What are the types of in vitro cytotoxicity test methods?
Following are the different methods that can be used for invitro cytotoxicity testing.
- Trypan blue exclusion assay:
Researchers use the trypan blue exclusion assay to calculate the cell number and percentage of viable cells in a cell population using trypan blue dye. This dye is permeable for dead cells but impermeable for normal cells due to a damaged plasma membrane.
- Propidium iodide uptake assay:
Propidium iodide (PI) staining is a technique that uses a fluorescent molecule to stain DNA in cells.
- MTT (3-(4,5-Dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assay:
The MTT assay is defined as a method that measures cellular metabolic activity by assessing the reduction of MTT to purple formazan crystals primarily by mitochondrial dehydrogenases, providing insights into cytotoxicity levels in cell lines and primary cell. Formazan is a water-insoluble dark-blue/purple product that’s created when the mitochondrial dehydrogenase enzyme in living cells reduces the yellow water-soluble MTT substrate. The amount of formazan formed is directly proportional to the number of viable cells.
- Alamar Blue assay:
Alamar Blue is a direct indicator of cell health, it detects the level of oxidation during respiration, quantitatively measuring cell viability and cytotoxicity. It is widely used to study cytotoxicity, proliferation, and metabolic activity within the cell.
Q.3 What are the advantages of in vitro cytotoxicity test methods?
- Rapid: In vitro cytotoxicity assays are rapid.
- Inexpensive: In vitro cytotoxicity assays are inexpensive.
- Animal-free: In vitro cytotoxicity assays do not require the use of animals.
- High throughput: Researchers can use in vitro cytotoxicity assays to test a large number of samples.
Q.4 What are Applications of in vitro cytotoxicity test methods?
- Drug discovery
- Medical device evaluation
- Cancer research
- Safety assessment
- Study of Environmental pollutants
