3.3.4  Conductometry
Conductometry methods are those in which the conductivity of the sample solution is monitored using a low-amplitude alternating electrical potential (Dzyadevych and Jaffrezic-Renault, 2014). The principle relies on conductivity change in the sample via the production or consumption of charged species. The measurement has the advantage of not requiring a reference electrode and can be used to detect both electroactive and electroinactive analytes (Jaffrezic-Renault and Dzyadevych, 2008; Narayan, 2016). Given the method can be performed using a two-electrode configuration, conductometric biosensors can be easily miniaturized. In addition, they are less vulnerable to many types of interference due to their differential measurement mode (Jaffrezic-Renault and Dzyadevych, 2008).
As shown in Fig. 5d, Yoo et al. used a conductometric biosensor with CNT-based electrodes for the detection of B. subtilis (Yoo et al. 2017). Mannoor et al. used a previously described conductometric biosensor to detect S. aureus and Helicobacter pylori on tooth enamel (Mannoor et al. 2012). Shen et al. detected two strains of human influenza A virus (H1N1 and H3N2) using conductometry with a silicon nanowire array at a LOD of 29 viruses/μL (Shen et al. 2012). Additional studies that have examined the use of conductometric biosensors for pathogen detection can be found in Table 1, Table 2.