Measurement of viscosity in living cells by a fluorescence method

Abstract

Yeast and Euglena gracilis take up fluorescein diacetate and hydrolyze it to fluorescein in the cells. Fluorescence polarization of fluorescein in cells can be measured accurately in cell suspensions and related to intracellular viscosity. For yeast at 15°C and 27°C, internal viscosities of 14 cp and 10 cp are found and for Euglena values of 6.3 cp and 5.2 cp are found.