<p>The effects of pharmacological substances on viruses in drug screening has been measured indirectly via the observation of cytopathic effects on cultured cells. To quantify directly the pharmacological effects of compounds on microorganisms, we devised a method that measures the direct impact by assessing the permittivity due to the lipid bilayer membrane. In the present study, we constructed an electrode-replaceable measuring cell using 3D printing technology to demonstrate the feasibility of permittivity measurements in microorganisms. We conducted measurements of the permittivity of a KCl solution, as well as a KCl solution containing suspended liposomes or yeast cells. We found an increase in permittivity that can be ascribed to the lipid bilayers of the liposomes and yeast cells, within a frequency range of 10⁴–10⁸ Hz. Following the induction of liposome lysis via the application of Triton-X 100, we observed a reduction in the increased permittivity. Furthermore, when the yeast cell count was reduced by dilution, there was a corresponding decrease in the enhanced permittivity. A decrease in permittivity was also measured in yeast cells suspended in a KCl solution following heat and enzyme treatments. These results suggest that the permittivity of a lipid bilayer membrane can be measured to estimate the concentration of microorganisms in a solution and our method is expected to provide a novel assay for the preliminary screening of potential drugs aimed at microorganisms. </p><p></p>