title: Cu nanoclusters-based ratiometric fluorescence probe for ratiometric and visualization detection of copper ions.
abstract: Copper is a highly toxic environmental pollutant with bioaccumulative properties. Therefore, sensitive detection of Cu(2+) is very important to prevent over-ingestion, and visual detection is preferred for practical applications. In this work, we developed a simple and environmental friendly approach to synthesize hyperbranched polyethyleneimine-protected copper nanoclusters (hPEI-Cu NCs) with great stability against extreme pH, high ionic strength, thiols etching and light illumination, which were then conjugated to the surface of silica coated CdSe quantum dots (QDs) to design a ratiometric fluorescence probe. In the presence of different amounts of Cu(2+) ions, the fluorescence of Cu NCs can be drastically quenched, while the emission from QDs stayed constant to serve as a reference signal and the color of the probe changed from yellow-green to red, resulting in ratiometric and visualization detection of Cu(2+) ion with high accuracy. The detection limit for Cu(2+) was estimated to be 8.9 nM, much lower than the allowable level of Cu(2+) in drinking water (∼20 μM) set by U.S. Environmental Protection Agency. Additionally, this probe can be also applied for the determination of Cu(2+) ion in complex real water samples.
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
authors.forename: Zhi-Chao
authors.initials: ZC
authors.lastname: Liu
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Qi
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Hu
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China.
authors.forename: Ru-Ping
authors.initials: RP
authors.lastname: Liang
authors.affiliation: College of Chemistry and Institute for Advanced Study, Nanchang University, Nanchang 330031, China. Electronic address: jdqiu@ncu.edu.cn.
authors.forename: Jian-Ding
authors.initials: JD
authors.lastname: Qiu
keywords: Copper nanoclusters; Polyethyleneimin; Ratiometric fluorescence; Visualization