Measuring Intracellular Calcium Levels

Calcium levels within living cells can easily be measured using calcium-sinsitive fluorescent dyes created by Dr. Roger Tsien.

The dye is esterified which allows uptake by the cells. The esterase in the cell removes the ester, and the free dye cannot get out of the cell. Calcium binding changes the fluorescent dye properties of the fluorescent probe, allowing it to have enhanced fluorescent properties and a wavelength shift that can be assessed. The fluorescence can be measured on a fluorescence activated cell sorter.