Biology Reference
In-Depth Information
12.1 Introduction
12.1.1 Aim of Electrochemical DNA Biosensors
After the first biosensor was described by Clark and Lyons in 1962,
scientists design electrochemical DNA biosensors based on analyti-
calmethodologiesforavarietyofreasons.Theymaybeinterestedin
monitoring of DNA hybridization event for the detection of genetic
disease, genetically modified organism, biological warfare agent,
etc. The goal might be the analysis of a solution which contains
trace amounts of hazardous compound that may interact with DNA.
In these examples, electrochemical DNA biosensors (genosensors)
are employed as tools for the identification of DNA sequences
based on the hybridization event and DNA-compound interactions.
In this chapter, the terms and concepts employed in describing
DNA-compound interactions are introduced. Additionally, before
embarking on a detailed consideration of detection techniques and
mathematical equations that gave an idea for the mechanism of the
interactionbetweencompoundandDNA,wewillmentionaboutthe
structure of DNA and possiblebindingsitesof DNA for compounds.
12.2 The Structure of DNA
Deoxyribonucleic acid (DNA) is the most biologically significant
target for electrochemical biosensors for testing of hazardous com-
pounds. Binding of different molecules on DNA and the detection of
DNA damage have been monitored based on both electrochemical
signals of DNA and related compounds. Before the identification
of these interactions, we prefer to give a brief information about
DNA structure due to the importance of its binding sites for
compounds.
The individual DNA molcule which localized in eukaryotic
chromosomes are large polymers and they contain a linear back-
bone of alternating sugar and phosphate residues. DNA molecule
includes the five carbon sugar “deoxyribose,” and consecutive sugar
structures are linked by covalent phosphodiester bridge. Covalently
bonded to carbon atom number 1 (one prime) of each sugar is a
 
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