What is MTS Assay?
The
MTS assay is a colorimetric method used to assess cell metabolic activity. It is a popular alternative to the
MTT assay due to its greater sensitivity and the fact that it does not require a solubilization step. The assay uses a tetrazolium compound, MTS, which is reduced by living cells to form a formazan product that is soluble in cell culture media.
How Does the MTS Assay Work?
The MTS reagent is a tetrazolium compound that is reduced by dehydrogenase enzymes found in metabolically active cells. This reduction process occurs in the mitochondria, producing a soluble formazan dye. The amount of formazan produced is directly proportional to the number of living cells. The absorbance of the formazan dye can be measured using a spectrophotometer at 490 nm, providing a quantitative measure of cell viability.
Simplicity: The protocol is straightforward and can be completed in a relatively short period.
Non-destructive: The assay does not require cell lysis, allowing for further analysis on the same sample.
Sensitivity: The assay is highly sensitive, making it suitable for detecting subtle changes in cell viability.
Compatibility: The assay is compatible with high-throughput screening formats, making it ideal for large-scale studies.
Interference: Some nanomaterials can interfere with the assay by either reacting with the MTS reagent or absorbing at the same wavelength as the formazan product.
Specificity: The assay primarily measures metabolic activity, which may not always correlate with cell viability. Cells under stress may still be metabolically active.
Optimization: The assay conditions may need to be optimized for different cell types and nanomaterials.
Titration: Perform a titration of the nanomaterial to determine the optimal concentration range for the assay.
Controls: Include appropriate controls, such as cells without nanomaterials and nanomaterials without cells, to account for any background interference.
Incubation Time: Optimize the incubation time to ensure sufficient formazan production without causing cell death due to prolonged exposure.
Validation: Validate the results with complementary assays, such as
cell viability assays or
live/dead staining, to confirm the findings.
Conclusion
In conclusion, the MTS assay is a valuable tool in nanotechnology for assessing the cytotoxicity of nanomaterials. Its simplicity, sensitivity, and non-destructive nature make it a preferred choice for many researchers. However, careful optimization and consideration of potential interferences are essential to obtain accurate and reliable results. By addressing these challenges, the MTS assay can provide crucial insights into the biocompatibility of nanomaterials, facilitating their safe and effective application in various fields.
