Electrical impedance spectroscopy measurement of biologic materials provides information about viable cell density as well as cell size and shape homogeneity. Several experimental and even commercial biomass density probes have been developed both for cell suspensions and monolayer cell cultures in the last twenty years. This communication describes the development of a set of electrodes and circuits designed to add viable biomass density measurement capability to a set of single-use miniaturized bioreactors. Two applications: adherent animal cultures and generic cell suspension cultures drive to the need of providing two electrode sets and two measurement systems with different frequency ranges.