title: Fluorescein Tri-Aldehyde Promotes the Selective Detection of Homocysteine.
abstract: Elevated homocysteine levels are a well-known independent risk factor for cardiovascular disease. To date, relatively few selective fluorescent probes for homocysteine detection have been reported. The lack of sensing reagents and remaining challenges largely derive from issues of sensitivity and/or selectivity. For example, homocysteine is a structural homologue of the more abundant (ca, 20-25 fold) aminothiol cysteine, differing only by an additional methylene group side chain. Fluorescein tri-aldehyde, described herein, has been designed and synthesized as a sensitive and selective fluorophore for the detection of homocysteine in human plasma samples. It responds to analytes selectively via a photoinduced electron transfer (PET) inhibition process that is modulated by predictable analyte-dye product hybridization and ionization states. Mulliken population analysis of fluorescein tri-aldehyde and its reaction products reveals that the characteristic formation of multiple cationic of homocysteine-derived heterocycles leads to enhanced relative negative charge build up on the proximal phenolate oxygen of the fluorophore as a contributing factor to selective emission enhancement.
authors.affiliation: Department of Chemistry, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
authors.forename: Aabha
authors.initials: A
authors.lastname: Barve
authors.affiliation: Department of Chemistry, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Lowry
authors.affiliation: Department of Chemistry, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
authors.forename: Jorge O
authors.initials: JO
authors.lastname: Escobedo
authors.affiliation: Department of Chemistry, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
authors.forename: Josephrajan
authors.initials: J
authors.lastname: Thainashmuthu
authors.affiliation: Department of Chemistry, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA. strongin@pdx.edu.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Strongin
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D019793:Fluorescein / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D015394:Molecular Structure; D013050:Spectrometry, Fluorescence
chemical_list: D000447:Aldehydes; D005456:Fluorescent Dyes; D006710:Homocysteine; D019793:Fluorescein
keywords: Fluorescein aldehydes; Fluorescence; Homocysteine; Thiazinane; Thiazolidine