Chapter 16
Electrochemical Affinity and Nucleic Acid Sensors
This chapter introduces affinity and nucleic acid sensors based on dynamic electrochemistry transduction methods. Most of the methods reviewed here belong to the amperometric/voltammetric class, but applications of reciprocal derivative chronopotentiometry are also emphasized as this method provides excellent sensitivity in certain transduction processes based on irreversible electrochemical reactions.
In both classes of sensor presented in this chapter, the recognition occurs by formation of molecular complexes involving multiple noncovalent bonds. However, nucleic acid sensors present the particular feature of recognition by hydrogen bonding that involves specific nucleobase pairs.
Another common feature of sensors in both above classes is the extensive use of transduction labels that can be either enzymes or electrochemically active small molecules.
16.1 Amperometric Affinity Sensors
A great deal of research work on amperometric transduction in immunosensors has led to important advances in this field [1–4]. As compounds involved in immunosensing are usually not electrochemically active, amperometric immunosensors rely on labeling with either electrochemically-active compounds or redox enzymes.
Application of synthetic receptors (such as molecularly imprinted polymers) provides opportunities for substituting expensive and unstable antibodies with stable materials for the determination of small molecules. In this area, ...
