Measurements of complex permittivity and permeability in the GHz range of magnetotactic bacteria suspensions

Magnetotactic bacteria (MTB) cells contain chains of magnetosomes, which are magnetite nanocrystals enveloped in a lipid bilayer. A water-based suspension of cultured MTB was prepared and the electric and magnetic properties were measured by two methods: a reflection method using an open-ended coaxial probe (0.5-50 GHz) and a transmission method using a rectangular waveguide (8.2-12.4 GHz). Based on the very good agreement obtained for the measured complex permittivity of a saline solution with data in the literature, we report here the results of both the complex permittivity and permeability of a suspension of cultured MTB.