Derivation and Numerical Verification of a Compact Analytical Model for the AC Admittance Response of Nanoelectrodes, Suitable for the Analysis and Optimization of Impedance Biosensors

This paper presents a compact analytical model for the AC response of nanoelectrode-based impedimetric biosensors to dielectric nanoparticles suspended in the electrolyte. The model highlights the functional dependence of the impedance change on the nanoparticle and the system geometrical and physical parameters. The model is carefully verified by means of 2-D simulations carried out with an ad hoc numerical solver of the Poisson–Nernst–Planck (Poisson-Drift-Diffusion) equations. The results can be useful to determine optimum detection conditions for impedimetric nanobiosensors, and to interpret experimental results.