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Graphene Oxide and Metal‐Mediated Base Pairs Based “Molecular Beacon” Integrating with Exonuclease I for Fluorescence Turn‐on Detection of Biothiols
Author(s) -
Xing Xiaojing,
Zhou Ying,
Liu Xueguo,
Pang Daiwen,
Tang Hongwu
Publication year - 2014
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201302938
Subject(s) - exonuclease iii , fluorescence , chemistry , detection limit , graphene , glutathione , metal ions in aqueous solution , combinatorial chemistry , molecular beacon , metal , exonuclease , cysteine , biosensor , base pair , quenching (fluorescence) , photochemistry , dna , biochemistry , nanotechnology , materials science , oligonucleotide , chromatography , enzyme , organic chemistry , escherichia coli , quantum mechanics , dna polymerase , gene , physics
A novel fluorescence turn‐on strategy, based on the resistance of metal‐mediated molecular‐beacons (MBs) toward nuclease digestion and the remarkable difference in the affinity of graphene oxide (GO) with MBs and the mononucleotides, is designed for the biothiols assay. Specifically, the metal‐mediated base pairs facilitate the dye labeled MBs to fold into a hairpin structure preventing the digestion by exonuclease I, and thus allow the fluorescence quenching. The competition binding by biothiols removes metal ions from the base pairs, causing the nuclease reaction, and less decrease in the fluorescence is obtained after incubating with GO due to the weak affinity of the product‐mononucleotides to GO. Hg 2+ ‐mediated MBs were firstly designed for the biothiols detection, and glutathione (GSH) was applied as the model target. Under the optimal conditions, the approach exhibits high sensitivity to GSH with a detection limit of 1.53 nM. Ag + ‐mediated MBs based sensor was also constructed to demonstrate its versatility, and cysteine was studied as the model target. The satisfactory results in the determination of biothiols in serum demonstrate that the method possesses great potential for detecting thiols in biological fluids. This new approach is expected to promote the exploitation of metal‐mediated base pairs‐based biosensors in biochemical and biomedical studies.