title: Cyclodextrin supramolecular inclusion-enhanced pyrene excimer switching for time-resolved fluorescence detection of biothiols in serum.
abstract: We report here an efficient pyrene excimer signaling-based time-resolved fluorescent sensor for the measurement of biothiols (cysteine (Cys), homocysteine (Hcy), glutathione (GSH)) in human serum based on thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and the inclusion interaction of cyclodextrin. The sensing mechanism of the approach is based on the competitive ligation of Hg(2+) ions by Hcy/Cys/GSH and T-T mismatches in a bis-pyrene-labeled DNA strand with the self-complementary 5' and 3' ends. The introduction of γ-cyclodextrin can provide cooperation for the molecular level space proximity of the two labeled pyrene molecules, moreover the hydrophobic cavity of γ-cyclodextrin can also offer protection for the pyrene dimer's emission from the quenching effect of environmental conditions and enhance the fluorescence intensity of the pyrene excimer. When the biothiols are not presented, the sensing ensemble is in the "off" state due to the long distance between the two labeled pyrene molecules resulted from the formation of a more stable T-Hg(2+)-T structure. While in the presence of biothiols, Hg(2+) interacts very strongly with thiol groups and the T-Hg(2+)-T structure is dehybridized, and then the pyrene excimer will be formed due to the self-complementary 5' and 3' ends of the DNA probe and the cooperation interaction of γ-cyclodextrin to pyrene dimer, thus resulting in switching the sensing ensemble to the "on" state. In the optimum conditions described, the linear concentration range of 1.0-100 μM with the limit of detection (LOD) of 0.36 μM for GSH was obtained. Moreover, due to the much longer lifetime of the pyrene excimer fluorescence than those of the ubiquitous endogenous fluorescent components, the time-resolved fluorescence technique has been successfully used for application in complicated biological samples.
authors.affiliation: Institute of Applied Chemistry, School of Science, Central South University of Forestry and Technology, Changsha 410004, China; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Qier
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Institute of Applied Chemistry, School of Science, Central South University of Forestry and Technology, Changsha 410004, China; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China. Electronic address: muzi_dt@hotmail.com.
authors.forename: Ting
authors.initials: T
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Jishan
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Weijian
authors.initials: W
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D015374:Biosensing Techniques; D003505:Cyclodextrins / Q000737:chemistry; D003545:Cysteine / Q000097:blood* / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry; D005453:Fluorescence; D005978:Glutathione / Q000097:blood* / Q000737:chemistry; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D057230:Limit of Detection; D011721:Pyrenes / Q000737:chemistry
chemical_list: D003505:Cyclodextrins; D015342:DNA Probes; D011721:Pyrenes; D006710:Homocysteine; C030984:pyrene; D005978:Glutathione; D003545:Cysteine
keywords: Biothoils; Inclusion interaction; Pyrene excimer; Thymine–Hg(2+)–thymine coordination chemistry; Time-resolved fluorescence technique