title: Selective turn-on fluorescence assay of 6-thioguanine by using harmine-modified silver nanoparticles.
abstract: This article reports on a novel fluorescence resonance energy transfer (FRET) system between harmine and silver nanoparticles (AgNPs), in which harmine acts as the donor and AgNPs act as the acceptor. As a result of FRET, harmine fluorescence is quenched efficiently with a corresponding Stern-Volmer constant of 3.61 × 10(11)  L/mol. It was found that upon addition of the anticancer drug, 6-thioguanine (6-TG), the fluorescence was recovered due to the competitive adsorption of this compound onto AgNPs. Based on this effect, a selective turn-on fluorescence sensor was developed for the determination of 6-TG. Under optimum conditions, the enhanced fluorescence intensity displays a linear relationship with the concentration of 6-TG in the range 1.5 × 10(-8) -7.5 × 10(-7)  M with a detection limit of 9.7 nM. The developed method was applied to the determination of this drug in a pharmaceutical preparation and human plasma samples.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, 5166616471, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Amjadi
authors.forename: Leila
authors.initials: L
authors.lastname: Farzampour
mesh_terms: D000327:Adsorption; D000970:Antineoplastic Agents / Q000032:analysis*; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer; D006247:Harmine / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013607:Tablets / Q000032:analysis; D013866:Thioguanine / Q000032:analysis*
chemical_list: D000970:Antineoplastic Agents; D013607:Tablets; D012834:Silver; D006247:Harmine; D013866:Thioguanine
keywords: 6-thioguanine; fluorescence resonance energy transfer; harmine; quenching; silver nanoparticles