title: Quantum dots-based ratiometric fluorescence probe for mercuric ions in biological fluids.
abstract: Fluorescence analysis by means of a single fluorescence signal output usually leads to the signal fluctuation caused by various external factors. Ratiometric fluorescence probes that can significantly eliminate the external effects by self-calibration of two different emission bands are preferable for the detection of real samples. In this work, we designed a dual-emission quantum dots (QDs) nanocomposite as a ratiometric probe for the visual detection of Hg(2+). The dual-emission QDs nanocomposite consists of two differently sized CdTe/CdS QDs. The red-emitting larger sized CdTe/CdS QDs embeded in silica nanoparticles are insensitive to Hg(2+), while the green-emitting smaller sized ones are covalently conjugated onto the silica nanoparticles surface and sensitive to Hg(2+). The addition of Hg(2+) can only quench green fluorescence in the dual-emission QDs nanocomposites, which triggers the change of fluorescence intensity ratio of two different emission wavelengths and hence induces the evolution of fluorescence color of the probe solution with variation of Hg(2+) concentration. Based on this feature, the dual-emission QDs nanocomposites can be used to develop a ratiometric fluorescence probe for the visual detection of Hg(2+). Under the optimized conditions, the ratiometric fluorescence QDs probe shows a linear relationship between fluorescence intensity ratio and Hg(2+) concentration in the range of 5-300 nM. The detection limit of this probe was found to be 3.1 nM. This ratiometric assay also exhibits a high selectivity and it has been successfully used in the determination of Hg(2+) content in fetal bovine serum and human urine.
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Mu
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China. Electronic address: xuhuzs@gmail.com.
authors.forename: Hu
authors.initials: H
authors.lastname: Xu
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, China. Electronic address: zhongxh@ecust.edu.cn.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Zhong
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000737:chemistry*; D002417:Cattle; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000032:analysis* / Q000097:blood / Q000652:urine; D053758:Nanoparticles; D045663:Quantum Dots; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D012822:Silicon Dioxide; D008628:Mercury
keywords: Dual-emission probe; Mercuric ions; Quantum dots; Ratiometric fluorescence