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Nucleic Acid Aptamers: An Emerging Tool for Biotechnology and Biomedical Sensing.

Ku TH, Zhang T, Luo H, Yen TM, Chen PW, Han Y, Lo YH - Sensors (Basel) (2015)

Bottom Line: Detection of small molecules or proteins of living cells provides an exceptional opportunity to study genetic variations and functions, cellular behaviors, and various diseases including cancer and microbial infections.Our aim in this review is to give an overview of selected research activities related to nucleic acid-based aptamer techniques that have been reported in the past two decades.Limitations of aptamers and possible approaches to overcome these limitations are also discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093-0407, USA. tiku@eng.ucsd.edu.

ABSTRACT
Detection of small molecules or proteins of living cells provides an exceptional opportunity to study genetic variations and functions, cellular behaviors, and various diseases including cancer and microbial infections. Our aim in this review is to give an overview of selected research activities related to nucleic acid-based aptamer techniques that have been reported in the past two decades. Limitations of aptamers and possible approaches to overcome these limitations are also discussed.

No MeSH data available.


Related in: MedlinePlus

Chemical structure of theophylline, caffeine, L-arginine and D-arginine.
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sensors-15-16281-f002: Chemical structure of theophylline, caffeine, L-arginine and D-arginine.

Mentions: The word “aptamer” was derived from the Latin aptus—meaning “to fit”, and Greek meros—meaning “region” [1]. Nucleic acid aptamers are single strands of DNA or RNA (and chemically-modified DNA or RNA) with a length in the range of 10–100 nucleotides (nt), which are identified from an in vitro selection process: “systemic evolution of ligands by exponential enrichment (SELEX)” [2]. Over multiple rounds, the SELEX process allows isolation of functional oligonucleotide sequences that can recognize a specific target from a random single-stranded (ss)DNA or RNA library. Within the nucleic acid library, some sequences are folded into unique three-dimensional structures, possessing a combination of loops, stems, hairpins, pseudoknots, bulges, or G-quadruplexes [3,4,5,6]. The aptamer-target recognition was through intermolecular interactions such as aromatic rings, pi-pi system stacking, van der Waals and electrostatic interactions between charged groups and hydrogen bonding. Sometimes it requires the aptamer to undergo adaptive conformational changes and have their three-dimensional structure folded to a unique binding conformation for its target. Aptamers have high target chemical structure specificity, which makes it possible to discriminate a specific molecule from its analogues. Theophylline, a methylxanthine drug, is used for respiratory diseases treatment such as chronic obstructive pulmonary disease (COPD) and asthma. Because of its narrow therapeutic index, serum levels must be monitored carefully to avoid life-threatening toxicity [7]. Theophylline is chemically similar to caffeine, which is present in serum samples. Thus, diagnostic methods must discriminate efficiently among these compounds. The theophylline-binding aptamer shows an affinity for its cognate ligand 10,000-fold higher than that of caffeine, which differs from theophylline by only a single methyl group at nitrogen atom N-7. Enantioselective, a low molecular weight aptamer shows 12,000-fold stronger affinity with L-arginine than with D-arginine. Figure 2 shows the chemical structures of those small molecules mentioned above [8,9].


Nucleic Acid Aptamers: An Emerging Tool for Biotechnology and Biomedical Sensing.

Ku TH, Zhang T, Luo H, Yen TM, Chen PW, Han Y, Lo YH - Sensors (Basel) (2015)

Chemical structure of theophylline, caffeine, L-arginine and D-arginine.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541879&req=5

sensors-15-16281-f002: Chemical structure of theophylline, caffeine, L-arginine and D-arginine.
Mentions: The word “aptamer” was derived from the Latin aptus—meaning “to fit”, and Greek meros—meaning “region” [1]. Nucleic acid aptamers are single strands of DNA or RNA (and chemically-modified DNA or RNA) with a length in the range of 10–100 nucleotides (nt), which are identified from an in vitro selection process: “systemic evolution of ligands by exponential enrichment (SELEX)” [2]. Over multiple rounds, the SELEX process allows isolation of functional oligonucleotide sequences that can recognize a specific target from a random single-stranded (ss)DNA or RNA library. Within the nucleic acid library, some sequences are folded into unique three-dimensional structures, possessing a combination of loops, stems, hairpins, pseudoknots, bulges, or G-quadruplexes [3,4,5,6]. The aptamer-target recognition was through intermolecular interactions such as aromatic rings, pi-pi system stacking, van der Waals and electrostatic interactions between charged groups and hydrogen bonding. Sometimes it requires the aptamer to undergo adaptive conformational changes and have their three-dimensional structure folded to a unique binding conformation for its target. Aptamers have high target chemical structure specificity, which makes it possible to discriminate a specific molecule from its analogues. Theophylline, a methylxanthine drug, is used for respiratory diseases treatment such as chronic obstructive pulmonary disease (COPD) and asthma. Because of its narrow therapeutic index, serum levels must be monitored carefully to avoid life-threatening toxicity [7]. Theophylline is chemically similar to caffeine, which is present in serum samples. Thus, diagnostic methods must discriminate efficiently among these compounds. The theophylline-binding aptamer shows an affinity for its cognate ligand 10,000-fold higher than that of caffeine, which differs from theophylline by only a single methyl group at nitrogen atom N-7. Enantioselective, a low molecular weight aptamer shows 12,000-fold stronger affinity with L-arginine than with D-arginine. Figure 2 shows the chemical structures of those small molecules mentioned above [8,9].

Bottom Line: Detection of small molecules or proteins of living cells provides an exceptional opportunity to study genetic variations and functions, cellular behaviors, and various diseases including cancer and microbial infections.Our aim in this review is to give an overview of selected research activities related to nucleic acid-based aptamer techniques that have been reported in the past two decades.Limitations of aptamers and possible approaches to overcome these limitations are also discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093-0407, USA. tiku@eng.ucsd.edu.

ABSTRACT
Detection of small molecules or proteins of living cells provides an exceptional opportunity to study genetic variations and functions, cellular behaviors, and various diseases including cancer and microbial infections. Our aim in this review is to give an overview of selected research activities related to nucleic acid-based aptamer techniques that have been reported in the past two decades. Limitations of aptamers and possible approaches to overcome these limitations are also discussed.

No MeSH data available.


Related in: MedlinePlus