Xtt Assay
Xtt Assay - Related Videos
03:20
XTT Assay: A Colorimetric Assay to Assess Cell Viability and Mitochondrial Activity
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2023
This article describes the protocol for XTT assay which is a colorimetric assay to assess cell viability and mitochondrial activity.
03:10
An Assay to Study the Impact of Photodynamic Treatment with a Photosensitizer on Macrophage Metabolic Activity
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2025
Source:Uju L. Madu1, Nozethu Mjokane1, Maphori Maliehe1, Olihile M. Sebolai11Department of Microbiology and Biochemistry, University of the Free State.The video demonstrates a technique for evaluating the influence of photodynamic treatment (PDT) with a photosensitizer on the metabolic activity of murine macrophages. The cells undergo treatment with the photosensitizer followed by exposure to UV light, initiating PDT. This process triggers the photosensitizer to generate reactive oxygen species...
03:54
An In Vitro Assay to Evaluate the Effect of Antibodies on Candida tropicalis Biofilm
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2025
This video demonstrates an in vitro technique to study the effect of antibodies on fungal biofilms. The pathogenic fungus Candida tropicalis secretes a virulence factor secreted aspartyl proteinase 2 (Sap2), facilitating biofilm formation. Upon introducing a heat-inactivated serum containing Sap2-specific antibodies that inhibit biofilm maturation, the viability of the fungal cells is assessed using a chromogenic assay.
08:12
The TUNEL Assay
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2023
One of the hallmarks of apoptosis is the nuclear DNA fragmentation by nucleases. These enzymes are activated by caspases, the family of proteins that execute the cell death program. TUNEL assay is a method that takes advantage of this feature to detect apoptotic cells. In this assay, an enzyme called terminal deoxynucleotidyl transferase catalyzes the addition of dUTP nucleotides to the free 3’ ends of fragmented DNA. By using dUTPs that are labeled with chemical tags that can produce...
09:12
Aortic Ring Assay
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Cited by 42 •
2009
Angiogenesis, the sprouting of blood vessels from pre-existing vasculature, is associated with both natural and pathological processes. Here we demonstrate an aortic ring assay that allows angiogenic potentiators and inhibitors to be directly added to aortic rings in culture. Sprouting and neovessel outgrowth can be determined by inspecting the aortic rings over a period of 6-12 days.
FAQs
Cellular dehydrogenases provide the reducing activity that converts yellow XTT into orange, water-soluble formazan. Because this reaction depends on activity in living cells, the resulting color links the optical signal to cellular viability and metabolism. Measuring absorbance therefore gives researchers a quantitative way to compare how treatments alter cell-associated metabolic activity across experimental conditions.
An absorbance reading reflects both the number of viable cells and the metabolic activity of those cells, rather than serving as a direct count of cell number alone. This distinction matters when interpreting treatment results: a change in signal may indicate altered viability, altered metabolism, or both. Comparisons are most informative when experimental conditions are evaluated consistently.
Compared with radioactive measurement formats, the XTT assay provides a nonradioactive approach with a straightforward optical readout. The water-soluble orange formazan product can be measured by spectrophotometry, connecting the biochemical reaction to a numerical signal. This combination is useful when studies need quantitative comparisons of treatment responses in cancer research, pharmacology, toxicology, or screening.
Researchers expose cells to the treatments being studied, allow the cellular reaction with XTT to generate the colored formazan product, and measure the resulting absorbance with a spectrophotometer. They then compare optical signals across conditions to estimate relative changes in viability or metabolic activity. This workflow supports direct evaluation of treatment effects within the chosen experimental design.
The assay can reveal whether a drug or other compound changes cell-associated metabolic activity and estimated viability. Researchers can use differences in absorbance to compare treatment conditions, investigate cytotoxic effects, or assess patterns consistent with changes in cell proliferation. These measurements support compound evaluation in experiments where treatment response is the primary outcome.
Its quantitative optical readout supports studies that compare how cells respond to different treatments, while its nonradioactive format suits routine biomedical experiments. In medicine-related research, applications include cancer investigations, pharmacology, toxicology, and compound screening. The assay therefore helps connect cellular metabolic responses with questions about treatment effects and potential cytotoxicity.