Be careful when using XTT. The XTT solution is not stable in culture
environment and will convert to formazan slowing without being reduced
with mitochondrial enzyme. Be sure to run severl control blanks every
time.
In our lab, we found MTT is more stable, and solubilization is not a
problem. As suggested earlier, incubation at 37C over night dissolves
MTT-formazan nicely.
