MTT Assay

Definition

The MTT assay is a colorimetric assay that measures cell viability based on the reduction of the yellow MTT dye to purple formazan crystals by metabolically active cells. This method is commonly used in both 2D and 3D cell culture systems to assess cellular health, proliferation, and cytotoxicity by quantifying the number of living cells.

5 Must Know Facts For Your Next Test

1. The MTT assay is non-toxic and allows for the quantification of live cells by measuring the absorbance of the colored formazan product at a specific wavelength, typically around 570 nm.
2. This assay can be used in both adherent (2D) and suspended (3D) cell cultures, making it versatile for different experimental setups.
3. MTT assays are widely applied in drug discovery and development to evaluate the cytotoxic effects of potential therapeutics on cancer and other cell types.
4. One limitation of the MTT assay is that it cannot distinguish between live, non-viable, and apoptotic cells; thus, it should be combined with other assays for a comprehensive analysis.
5. To perform an MTT assay, cells are typically incubated with MTT solution for several hours before adding a solvent to dissolve the formazan crystals for analysis.

Review Questions

• How does the MTT assay indicate cell viability and what are its implications in evaluating treatments?
  • The MTT assay indicates cell viability by measuring the reduction of MTT dye to purple formazan crystals by metabolically active cells. This process reflects the overall health and proliferative capacity of the cells. Evaluating treatments through this assay can help researchers determine the effectiveness and safety of new drugs or therapies by showing how well they preserve or compromise cell viability.
• Discuss how the use of the MTT assay in 2D versus 3D cell cultures may influence the interpretation of results.
  • Using the MTT assay in 2D cell cultures typically allows for straightforward quantification of viable cells since they grow in a uniform layer. However, in 3D cultures, cells interact more naturally with their environment, which can affect metabolic activity and responses to treatments. As a result, data obtained from 3D cultures might provide more physiologically relevant insights but could also introduce variability that complicates result interpretation compared to simpler 2D systems.
• Evaluate the advantages and limitations of the MTT assay in research, particularly focusing on its application in drug discovery.
  • The MTT assay offers significant advantages in drug discovery, such as ease of use, cost-effectiveness, and the ability to quickly assess cell viability across multiple conditions. However, its limitations include an inability to distinguish between live and dead cells or accurately assess cell health post-apoptosis. This means researchers must complement it with other assays to fully understand how compounds affect cellular behavior. Therefore, while useful as an initial screening tool, reliance solely on MTT could lead to incomplete conclusions regarding drug efficacy.

Related terms

Cell Viability: The ability of cells to survive and function under specific conditions, often assessed using assays like MTT to determine the effectiveness of drugs or treatments.

Formazan: A purple crystalline product formed when MTT dye is reduced by viable cells, which can be dissolved in a solvent for quantitative measurement.

Cytotoxicity: The quality of being toxic to cells, often evaluated using assays such as MTT to determine the potential harmful effects of substances on cell health.