MTT Assay

Definition

The MTT assay is a colorimetric assay used to measure cell viability, proliferation, and cytotoxicity based on the reduction of the yellow MTT dye to purple formazan crystals by metabolically active cells. This method is widely utilized in in vitro testing methods to assess the effects of compounds on cell health and is especially useful for screening drugs and determining the efficacy of potential therapeutic agents.

5 Must Know Facts For Your Next Test

1. The MTT assay is based on the principle that viable cells can convert MTT into formazan, indicating metabolic activity.
2. It is a quick and efficient method for assessing cell viability and is often used in high-throughput screening applications.
3. The intensity of the purple color produced in the assay correlates with the number of viable cells, allowing for quantification using spectrophotometry.
4. MTT assays can be performed on various cell types, making it a versatile tool in toxicology and pharmacology research.
5. The assay is sensitive to experimental conditions such as pH and incubation time, which can affect results and must be carefully controlled.

Review Questions

• How does the MTT assay determine cell viability, and what is the significance of the purple formazan crystals formed?
  • The MTT assay determines cell viability by measuring the ability of living cells to reduce MTT dye into purple formazan crystals. This reduction occurs in metabolically active cells, making the presence of formazan directly proportional to cell viability. The significance lies in its use as an indicator of cellular health and function, allowing researchers to evaluate the effects of various treatments on cell populations.
• Discuss how the MTT assay can be utilized in drug screening and its advantages compared to other viability assays.
  • The MTT assay can be utilized in drug screening by assessing the cytotoxic effects of potential therapeutic agents on cultured cells. Its advantages include rapid execution, compatibility with high-throughput systems, and ease of quantification through spectrophotometry. These features make it particularly valuable for early-stage drug development where large numbers of compounds need to be evaluated quickly.
• Evaluate the limitations of the MTT assay and how they may impact data interpretation in toxicological studies.
  • The limitations of the MTT assay include its sensitivity to experimental conditions such as pH, incubation time, and the presence of substances that may interfere with dye reduction or formazan solubilization. These factors can lead to misleading results if not properly controlled. In toxicological studies, this can impact data interpretation by either overestimating or underestimating cell viability, thus influencing conclusions about the safety and efficacy of tested compounds.

Related terms

Cell Viability: A measure of the proportion of living cells within a population, often determined by assays like MTT that indicate metabolic activity.

Cytotoxicity:

The quality of being toxic to cells, often assessed through assays that determine the effect of substances on cell survival and function.

Formazan: The purple crystalline product formed from the reduction of MTT by living cells, which can be solubilized and quantified to assess cell viability.