Bioelectromagnetics 7: 95-99 (1 986) zy Brief Communication Conductivity Values of Tissue Culture Medium From 20 zyx OC to 40 OC A.P. Mazzoleni, B.F. Sisken, and R.L. Kahler Wenner Gren Research Laboratory and the Department of Anatomy, University of Kentucky, Lexington zyxwvutsr Few studies are available that relate conductivity and temperature in solutions commonly used in tissue culture media. The purpose of this paper is to provide equations relating conductivity and temperature (in the range 20 zyxwv "C-40 "C) for five solutions: 0.9% saline, MEM (Minimum Essential Media), horse serum, MEM with 1 % horse serum, and MEM with 10% horse serum. zyxwvuts Key words: conductivity, culture medium, electric fields In vitro (tissue culture) models have been used to determine the effects of externally applied electrical fields on various types of biological systems. Such studies have employed direct current (DC) [Marsh and Beams, 1946; Sisken and Smith, 1975; Po0 and Robinson, 1977; Jaffe and Poo, 1979; Sisken et al, 1984, 19851, capacitively coupled fields [Brighton et al, 19841, pulsed electromagnetic fields (PEMF) [Sisken et al, 1984, 19851, and oscillating [Rodan et al, 19781 and pulsing current [Aro et al, 19841. In all cases, tissue culture media containing various concentrations of conductive salt solutions and serum concentrations of 1- 10 % were used. Determinations of the magnitude of the electric field are dependent upon the conductivity of the culture medium. Few studies [Geddes and Baker, 19671 are available that report conductivity values for saline, serum, and different tissues as a function of temperature; no values are available for tissue culture media. Since several investigators are attempting to correlate biological effects with specific levels of electric fields and current densities in vitro, precise conductivity values for tissue culture media used are needed. In this report we present data and equations describing a functional linear relationship between conductivity and temperature for five different solutions; the equations are valid from 20 "C to 40 "C. Received for review February 7, 1985; revision received August 12, 1985. Address reprint requests to Betty F. Sisken, Wenner Gren Research Laboratory, University of Kentucky, Lexington, KY 40506. zyxwvuts 0 1986 Alan R. Liss, Inc.