Nucleic Acids as Detection Tools

Abstract

In this chapter, we review some of the popular detection methods that utilize nucleic acids. First, we discuss assorted techniques in which nucleic acid probes are used to detect other nucleic acid sequences, followed by a discussion of functional nucleic acids and their applications as biosensors in conjunction with fluorescent, colorimetric, electrochemical and piezoelectric detection platforms. Detection of nucleic acid targets by nucleic acid probesSince many human diseases are linked to genetic perturbations, identification of specific mutations in patients has become a highly important practice in modern medicine. A great deal of DNA-based diagnostics pertain to identifying subtle differences in sequence content and their associated phenotypes. These differences are often the result of single nucleotide polymorphisms (SNPs) or other sequence alterations (such as point mutations, insertions and deletions). Since SNP is the most frequent form of genetic variation among individuals (roughly one for every 1000 nucleotides), many nucleic acid-based detection technologies are directed at identifying single-nucleotide differences [7,8].Apart from local genetic mutations, structural and distant site changes of DNA sequence are also observed. These large genomic alterations include insertion-deletions, gene copy number variants (CNVs), inversions and translocations, which have been linked to a variety of genetic disorders [9]. For instance, CNVs are characterized by atypical gene content and/or gene deregulation associated with CHARGE syndrome and Parkinson's and Alzheimer's disease [8,10,11]. Currently, there are a plethora of methods for detecting local and structural genetic changes, but here we will only discuss a few major techniques.

A Multiplexed, Two-Electrode Platform for Biosensing Based on DNA-Mediated Charge Transport

“…Analytical methods for reliable biomolecule detection are becoming increasingly important with the continued discovery of disease-related biomarkers. Electrochemical nucleic acid-based assays, − particularly those that utilize DNA-mediated charge transport (DNA CT), , are especially promising for sensing platforms. Devices based on DNA CT effectively report on the integrity of the π-stacked DNA bases; perturbations to the proper stacking, resulting from lesions, single nucleotide polymorphisms, or protein binding events that affect the base stack, attenuate the electrochemical signal.…”