Faradaic impedance spectroscopy monitors the change in insulation of the electrode surface in relation to a redox probe added to the electrolyte, which provides a Faradaic current. The binding of the target partial inhibits charge transfer and is observed by an increase in the real component of the impedance data i.e. R ct . A range of electrode modifications are used for Faradaic sensors including nanomaterials 204 , SAMs This layer coating the electrode must either be conductive or have sufficient gaps to allow for electron transfer. For this reason, when opting for alkanethiols, a mixed SAM layer is often chosen. SAM layers can also be coated with nanoparticles to decrease their R ct . Conductive polymers are also popular due to their unique electronic properties.