Molecular recognition elements, aptamers

Medley et al. have shown the use of aptamer-conjugated nanoparticles for cancer cell detection [50]. Herr et al. [51] have shown the rapid collection and detection of leukemia cells using a novel two-nanoparticle assay with aptamers as the molecular recognition element. 

In addition to antibodies, it is possible to use artificial nucleic acids ligands, known as aptamers, for the selective detection of proteins. The tight binding properties make aptamers attractive candidates as molecular recognition elements in a wide range of bioassays and for the development of protein arrays. Electrochemistry has been shown useful for monitoring aptamer-protein interactions (66). 

Molecular recognition is central to biosensor technology. Receptors, enzymes, antibodies, aptamers, molecular beacons, and nucleic acids are mainly used as molecular recognition elements in biosensor development (Chambers etal., 2008). Since 1990, nucleic acids, especially deoxyribonucleic acid (DNA) have been used as biorecognition elements in biosensor technology. These biosensors are named as DNA-based biosensors. 

Cao s group in 2011 designed an ECL biosensor based on the construction of triplex DNA for the detection of adenosine which employs an aptamer as a molecular recognition element and quenches ECL of Ru(bpy)3 by ferrocene monocarboxylic acid (FcA) G ig. 6.5). In the presence of adenosine, the aptamer sequence (Ru-DNA-1) more likely forms the aptamer—adenosine complex with hairpin configuration and the switch of the DNA-1 occurs in conjunction with the... 

Aptamers are oligonucleic acid or peptide molecules that can selectively bind a specific target molecule. Recently, for the determination of a small-molecule drug, a highly sensitive ECL aptamer-based biosensor has been constructed based on two components a cocaine-binding aptamer as molecular recognition element and as a model analyte and a Ru(II) complex as an ECL label [153]. 

Enantioselective Properties of Nucleic Acid Aptamer Molecular Recognition Elements... 

Despite being relatively new technology, aptamers have a tremendous potential and can be envisioned to rival antibodies and other traditional recognition elements for molecular detection and recognition, due to their inherent affinity, selectivity, and ease of synthesis. In addition, the combination of aptasensors with electrochemical detection methods has the added advantage of further cost reduction and miniaturization of such systems. 

The IUPAC definition may also be extended in respect to biomimetic recognition elements, e.g., aptamers and molecularly imprinted polymers, which are derived from biology (Table). 

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