Comparison of tetrapolar injection-measurement techniques for coplanar affinity-based impedimetric immunosensors

This paper focuses on tetrapolar coplanar-electrode affinity-based sensors. In a tetrapolar electrode systems there are different ways with which signals can be injected and measured. These injection and measurement methods, namely the Wenner, Dipole-Dipole and Cross techniques, are investigated in this paper by analyzing their sensitivity distribution. This is conducted with the use of FEM modeling. The results indicate that the Dipole-Dipole technique provides only a small negative sensitivity region near the electrode surface plane. On the other hand, regions of positive sensitivity dominate in the Wenner while regions of negative sensitivity dominate in the Cross techniques.