Analytes, molecular recognition

Molecular imprinting can be accomplished in two ways (a), the self assembly approach and (b), the preorganisation approach3. The first involves host guest complexes produced from weak intermolecular interactions (such as ionic or hydrophobic interaction, hydrogen bonding) between the analyte molecule and the functional monomers. The self assembled complexes are spontaneously formed in the liquid phase and are sterically fixed by polymerisation. After extraction of the analyte, vacant recognition sites specific for the imprint are established. Monomers used for self assembly are methacrylic acid, vinylpyridine and dimethylamino methacrylate. 

The use of additional membranes, which selectively convert nonionic analytes into ionic species that can be determined via ISEs is another common approach. An abundance of ingenious designs make use of biocatalysts for the development of potentiometric biosensors. Much of the earlier designs have made use of enzymes as the molecular recognition element. The products that are associated with such enzyme-catalyzed reactions can be readily monitored with the potentiometric transducer by coating the traditional electrodes with the enzyme. 

Christian Doppler Laboratory for Molecular Recognition Materials Department of Analytical Chemistry and Food Chemistry University of Vienna Vienna, Austria... 

In fields such as biosensing, analyte binding often relies on very specific molecular recognition interactions that nature has supplied, such as antibody-antigen interactions or strands of complimentary DNA forming double hefices. Unfortunately, because versatile and highly selective receptors for TNT or other explosive molecules are not available, chemists are left to rely on less specific interactions. 

The flow-through sensors described in this Section comply essentially with the definition of biosensor. This word, like every term used to designate devices of scientific and popular note, has been the object of a number of definitions of both generic and specific scope. In a broad sense, a biosensor is any instrument or technique that measures biomolecules. In stricter terms, Rechnitz defines a biosensor as "a device that incorporates a biochemical or biological component as a molecular recognition element and yields an analytical signal in response to biomolecules" [10]. In between these two... 

A selection of the most successful CSPs, chiral particles and chiral additive techniques used for analytical and preparative enantioseparation by LC is discussed in the following sections with respect to molecular recognition and experimental application. As additional sources of background information recent books and review articles2-16, which contain numerous relevant references and examine the most important aspects of the field of liquid chromatographic enantioseparation, should be consulted. 

A more recent application of redox labeled ODNs is redox-active aptamers that exploit molecular recognition between the aptamer and a target analyte. Briefly, aptamers are functional nucleic acids that selectively bind to a variety of targets. Due to a well-defined three-dimensional structure, aptamers can achieve selectivity comparable to that of antibodies but are readily accessible taking advantage of well-known nucleic acid chemistry, polymeric chain reaction and contemporary separation methods, followed by aptamer selection from random pools of nucleic acids (DNA or RNA) by in vitro selection process called systematic evolution of ligands by... 

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