Fig. 4.
(a–b) Ion-release impedance spectroscopy measurements from several heat-permeabilized liposome samples at concentrations ranging from 129.7 μl−1 to 50,131.5 μl−1 and (c) impedance measured at 2.6 kHz versus liposome concentration with fits to measurements above the limit of detection, approximately 1,000 μl−1. (d) Simplified circuit model of electrodes in solution which is fitted to experimental data, accounting for the dielectric capacitance Cdi, solution resistance Rsol, series resistance Rser, parasitic impedance Zpara, and interfacial impedance Zdl. (e–f) Sample fits of the simplified circuit model to measured data for high and low concentrations. (g) Bulk conductance calculated from values for Rsol extracted from fitting the experimental data are plotted versus liposome concentration and fitted with a straight line. The slope of this line represents the sensitivity of the device