The overall objective of this study was to develop a fluorescent chemosensor for cAMP by creating recognition sites for cAMP, that contain a fluorescent molecule, in a polymer matrix by molecular imprinting. Such a fluorescent molecularly imprinted polymer may, therefore, serve as both the recognition element and the measuring element for the fluorescent detection of cAMP in aqueous media. / Two new fluorescent molecules, known as 4-(p-dimethylaminostyryl)pyridinium salts or dyes, were synthesized as possible fluorescent components of a chemosensor. Upon excitation at 469 run, dye 1, trans-4-( p-N,N-dimethylaminostyryl)-N-vinylbenzyl-pyridinium chloride, displays a dramatic quantum yield enhancement in an emission band centered at ∼600 nm, with concomitant slight red shift of the emission maximum, in the presence of the cyclic nucleotides, cAMP and cGMP, in aqueous solution. Other purine nucleotides (AMP, ADP and ATP) and adenosine induce fluorescence quantum yield enhancements of lesser magnitude than those observed for cyclic nucleotides. The pyrimidine nucleotides, CMP and UMP, have almost no effect on the fluorescence of 1, suggesting a specificity of 1 for purine over pyrimidine analytes. Equilibrium association constants for 1 with the purine analytes, in aqueous solution (pH 7.2) range from 13.9 M --1 for cAMP to 0.15 M--1 for adenine. We conclude that the interaction of 1 with these analytes requires the presence of a purine base, and is enhanced by the presence of ribose and phosphate moieties. Dye 1 and a structurally-similar dye 2, trans-4-(p-N,N-dimethylaminostryl)-N-phenethylpyridinium bromide, also display dramatic fluorescence enhancements in the presence of DNA and proteins, suggesting that they also interact with these biomolecules. The environmentally-sensitive fluorescence of dyes 1 and 2 suggests that such compounds may be useful for developing fluorescent chemosensors for purine nucleotides, especially cAMP, and for the fluorescence detection or staining of DNA and proteins. / To increase the recognition ability of 1 for cAMP, we prepared recognition sites for cAMP that contain fluorescent dye 1 in a polymer matrix by molecular imprinting. This is a novel design for such template-selective sites, since dye 1 forms an integral part of the recognition cavity, thereby serving as both the recognition element and the measuring element for the fluorescence detection of cAMP in aqueous media. The polymer displays a concentration-dependent decrease in fluorescence in the presence of aqueous cAMP, whereas almost no effect is observed in the presence of the structurally-similar molecule, cGMP. An association constant of ∼105 M--1 was calculated for cAMP binding. Such fluorescent molecularly imprinted polymers could serve as a starting point in the development of highly effective synthetic fluorescent sensors for cAMP as well as other important biological molecules.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.37551 |
| Date | January 1998 |
| Creators | Turkewitsch, Petra. |
| Contributors | Powell, William S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Division of Experimental Medicine.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001635348, proquestno: NQ44611, Theses scanned by UMI/ProQuest. |
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