Figure 5.

Classification of estradiol aptasensors based on the aptamer and redox probe behaviors. (a) Impedance change by the aptamer conformation change. Examples of impedance increase (left) and decrease (right) are shown. (b) Change in the redox current by the aptamer conformation change. Examples of the current increase (left) and current decrease (right) are shown. (c) Change in redox current by the configuration change in aptamer complex (formation or decomposition). An example of current increase by graphene current channel formation is shown. (d) Change in the redox current by the configuration change in the aptamer complex. Examples of split aptamer binding (left) and complementary DNA/RNA decomposition (right) are shown.