title: Cu(2+) modulated silver nanoclusters as an on-off-on fluorescence probe for the selective detection of L-histidine.
abstract: In the present study, a new strategy based on Cu(2+) mediated DNA-templated silver nanoclusters (DNA-Ag NCs) was developed, as a label-free, on-off-on fluorescent probe for the detection of l-histidine. Eight synthesized DNA oligonucleotides (D1-D8) were experimentally tested, and D5-Ag NCs was finally selected for l-histidine detection due to its best fluorescent properties. The fluorescence emission of D5-Ag NCs could be quenched by Cu(2+) via electron or energy transfer. Upon addition of l-histidine, the chelation between Cu(2+) and the imidazole group of l-histidine leads to Cu(2+) liberation from D5-Ag NCs, and subsequently results in a dramatic fluorescence enhancement of the probe. The method displayed a good selectivity toward l-histidine over all the other amino acids, with a linear relationship in the range of 0.20-80μM, and a limit of detection (LOD) of 4.3nM. The strategy was also successfully applied to detect l-histidine in diluted human urine, exhibiting great opportunities for practical application in biological system.
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, China.
authors.forename: Xuyue
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, China. Electronic address: tmyao@tongji.edu.cn.
authors.forename: Tianming
authors.initials: T
authors.lastname: Yao
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, China. Electronic address: shishuo@tongji.edu.cn.
authors.forename: Shuo
authors.initials: S
authors.lastname: Shi
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006639:Histidine / Q000032:analysis / Q000652:urine*; D006801:Humans; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D012834:Silver; D006639:Histidine; D003300:Copper; D004247:DNA
keywords: DNA biosensor; Fluorescence; Silver nanoclusters; l-histidine