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Single-Stranded DNA Aptamers against Pathogens and Toxins: Identification and Biosensing Applications.

Hong KL, Sooter LJ - Biomed Res Int (2015)

Bottom Line: Molecular recognition elements (MREs) can be short sequences of single-stranded DNA, RNA, small peptides, or antibody fragments.There has been an increasing interest in the identification and application of nucleic acid molecular recognition elements, commonly known as aptamers, since they were first described in 1990 by the Gold and Szostak laboratories.Lastly, an overview of the basic principles of ssDNA aptamer-based biosensors is discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Pharmaceutical Sciences, 1 Medical Center Drive, P.O. Box 9530, Morgantown, WV 20506, USA.

ABSTRACT
Molecular recognition elements (MREs) can be short sequences of single-stranded DNA, RNA, small peptides, or antibody fragments. They can bind to user-defined targets with high affinity and specificity. There has been an increasing interest in the identification and application of nucleic acid molecular recognition elements, commonly known as aptamers, since they were first described in 1990 by the Gold and Szostak laboratories. A large number of target specific nucleic acids MREs and their applications are currently in the literature. This review first describes the general methodologies used in identifying single-stranded DNA (ssDNA) aptamers. It then summarizes advancements in the identification and biosensing application of ssDNA aptamers specific for bacteria, viruses, their associated molecules, and selected chemical toxins. Lastly, an overview of the basic principles of ssDNA aptamer-based biosensors is discussed.

No MeSH data available.


Related in: MedlinePlus

Illustration of examples of ssDNA MRE based electrochemical biosensors. (a) A representation of an “on-mode” system using a redox label for current transduction. (b) A representation of a “label-free” system by intercalating a redox label in a hairpin structure. (c) A representation of an “on-mode” system by hybridization with the complementary sequence.
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fig2: Illustration of examples of ssDNA MRE based electrochemical biosensors. (a) A representation of an “on-mode” system using a redox label for current transduction. (b) A representation of a “label-free” system by intercalating a redox label in a hairpin structure. (c) A representation of an “on-mode” system by hybridization with the complementary sequence.

Mentions: The principle of electrochemical detection is based on measuring changes in electrical properties of the sensing platform. In this method, ssDNA MRE is usually immobilized on a gold electrode via thiol-gold linkage. A redox label, such as methylene blue, can be used to detect binding between MRE and the target [262]. In a “signal on” system, the redox label is away from the electrode surface, and the binding of target causes a conformational change in the MRE and brings the redox label into close proximity with the electrode, thus causing a measurable change in electrical properties (Figure 2). A “signal off” system behaves similarly, but the binding of target causes the redox label to move away from the electrode. This system can also be modified as a “label-free” system, in which the redox molecule is intercalated in a hairpin structure of a MRE in a target unbound state, and binding of the target causes the release of the redox molecule (Figure 2). In addition to measuring redox current, the changes in impedance upon binding of the target can also be measured. In this case, no labeling of MRE is required and the conformational changes in MRE upon target binding cause a measurable change in impedance that can be recorded by voltammetry [212].


Single-Stranded DNA Aptamers against Pathogens and Toxins: Identification and Biosensing Applications.

Hong KL, Sooter LJ - Biomed Res Int (2015)

Illustration of examples of ssDNA MRE based electrochemical biosensors. (a) A representation of an “on-mode” system using a redox label for current transduction. (b) A representation of a “label-free” system by intercalating a redox label in a hairpin structure. (c) A representation of an “on-mode” system by hybridization with the complementary sequence.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493287&req=5

fig2: Illustration of examples of ssDNA MRE based electrochemical biosensors. (a) A representation of an “on-mode” system using a redox label for current transduction. (b) A representation of a “label-free” system by intercalating a redox label in a hairpin structure. (c) A representation of an “on-mode” system by hybridization with the complementary sequence.
Mentions: The principle of electrochemical detection is based on measuring changes in electrical properties of the sensing platform. In this method, ssDNA MRE is usually immobilized on a gold electrode via thiol-gold linkage. A redox label, such as methylene blue, can be used to detect binding between MRE and the target [262]. In a “signal on” system, the redox label is away from the electrode surface, and the binding of target causes a conformational change in the MRE and brings the redox label into close proximity with the electrode, thus causing a measurable change in electrical properties (Figure 2). A “signal off” system behaves similarly, but the binding of target causes the redox label to move away from the electrode. This system can also be modified as a “label-free” system, in which the redox molecule is intercalated in a hairpin structure of a MRE in a target unbound state, and binding of the target causes the release of the redox molecule (Figure 2). In addition to measuring redox current, the changes in impedance upon binding of the target can also be measured. In this case, no labeling of MRE is required and the conformational changes in MRE upon target binding cause a measurable change in impedance that can be recorded by voltammetry [212].

Bottom Line: Molecular recognition elements (MREs) can be short sequences of single-stranded DNA, RNA, small peptides, or antibody fragments.There has been an increasing interest in the identification and application of nucleic acid molecular recognition elements, commonly known as aptamers, since they were first described in 1990 by the Gold and Szostak laboratories.Lastly, an overview of the basic principles of ssDNA aptamer-based biosensors is discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Pharmaceutical Sciences, 1 Medical Center Drive, P.O. Box 9530, Morgantown, WV 20506, USA.

ABSTRACT
Molecular recognition elements (MREs) can be short sequences of single-stranded DNA, RNA, small peptides, or antibody fragments. They can bind to user-defined targets with high affinity and specificity. There has been an increasing interest in the identification and application of nucleic acid molecular recognition elements, commonly known as aptamers, since they were first described in 1990 by the Gold and Szostak laboratories. A large number of target specific nucleic acids MREs and their applications are currently in the literature. This review first describes the general methodologies used in identifying single-stranded DNA (ssDNA) aptamers. It then summarizes advancements in the identification and biosensing application of ssDNA aptamers specific for bacteria, viruses, their associated molecules, and selected chemical toxins. Lastly, an overview of the basic principles of ssDNA aptamer-based biosensors is discussed.

No MeSH data available.


Related in: MedlinePlus