XTT (sodium)

XTT (sodium) is used to assess cell viability as a function of redox potential. Actively respiring cells convert the water-soluble XTT to a water-soluble, orange colored formazan product. In Vitro:Determining Cell Viability Using XTT (sodium)^[2]
1. Solution Preparation
(1) XTT (sodium) solution:
Dissolve XTT in warm culture medium at a concentration of 1 mg/mL.
(2) PMS solution:
Prepare PMS solution at a concentration of 100 mM, dissolved in phosphate-buffered saline (PBS), and store at 4°C.
(3) Mixing for use:
When ready to use, add PMS solution to the XTT solution, resulting in a final PMS concentration of 25 μM.
2. Experimental Procedure
(1) Cell culture:
Seed the cells to be tested (e.g., HT-2 T cell line) in a 96-well plate, 100 μL medium per well, and incubate at 37°C for 40 hours.
(2) Add XTT/PMS solution:
Add 25 μL of the XTT/PMS solution to each well and incubate for 4-8 hours.
(3) Measure absorbance:
At the end of the incubation, measure the absorbance at 450 nm using a microplate reader, with 650 nm as the reference wavelength, and subtract the absorbance of the blank control wells.
3. Washing and Storage
Wash the experimental equipment with Milli-Q purified water. Store PMS and XTT solutions protected from light.
4. Notes
(1) XTT solution should be freshly prepared, and dissolving it in a 60°C water bath will be easier.
(2) The incubation time may vary depending on the experiment, and over-incubation can increase background noise.
(3) PMS solution has a short storage time and should be used within one month.