Electrochemical Methods of biosensors

Electrochemical biosensors are generally fairly simple devices. There are three types utilising electrical current, potential or resistive changes:
1. amperometric biosensors, which determine the electric current associated with the electrons involved in redox processes;
2. potentiometric biosensors, which use ion-selective electrodes to determine changes in the concentration of chosen ions (e.g. hydrogen ions); and
3. conductimetric biosensors, which determine conductance changes associated with changes in the ionic environment.
There has been much progress in miniaturising these devices using microfabrication technologies developed by the electronics industry.
These include the use of screen-printing and the deposition of nanolitre volumes of enzymes using advanced ink-jet printing and conducting inks.