Immunosensors frequency determination

Given the nature of the polymer and the conduction pathway, a simple homogeneous model cannot be applied to thin conducting polymer film-electrolyte systems [27,28,31]. For thin films (< lOOnm) with pore sizes estimated to range from 1 to 4 nm, the porous surface-electrolyte interface will dominate the electrical and physical properties of the sensor. Since the oxidation of the porous surface occurs first, the interface properties play a major role in determining device response. To make use of this information for the immunosensor response, the appropriate measurement frequency must be chosen to discriminate between bulk and interface phenomena. To determine the optimum frequency to probe the interface, the admittance spectra of the conducting polymer films in the frequency range of interest are required. 

Figure 14.10 Bode plot for the determination of the frequency dependence on the impedance and phase angle for the immunosensor. From Ref [30] with permission from Elsevier...

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