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Single Probe for Imaging and Biosensing of pH, Cu<sup>2+</sup> Ions, and pH/Cu<sup>2+</sup> in Live Cells with Ratiometric Fluorescence Signals

By Yingying Han (186431), Changqin Ding (1598539), Jie Zhou (28945) and Yang Tian (120718)


It is very essential to disentangle the complicated inter-relationship between pH and Cu in the signal transduction and homeostasis. To this end, reporters that can display distinct signals to pH and Cu are highly valuable. Unfortunately, there is still no report on the development of biosensors that can simultaneously respond to pH and Cu<sup>2+</sup>, to the best of our knowledge. In this work, we developed a single fluorescent probe, AuNC@FITC@DEAC (AuNC, gold cluster; FITC, fluorescein isothiocyanate; DEAC, 7-diethylaminocoumarin-3-carboxylic acid), for biosensing of pH, Cu<sup>2+</sup>, and pH/Cu<sup>2+</sup> with different ratiometric fluorescent signals. First, 2,2′,2″-(2,2′,2″-nitrilotris­(ethane-2,1-diyl)­tris­((pyridin-2-yl-methyl)­azanediyl))­triethanethiol (TPAASH) was designed for specific recognition of Cu<sup>2+</sup>, as well as for organic ligand to synthesize fluorescent AuNCs. Then, pH-sensitive molecule, FITC emitting at 518 nm, and inner reference molecule, DEAC with emission peak at 472 nm, were simultaneously conjugated on the surface of AuNCs emitting at 722 nm, thus, constructing a single fluorescent probe, AuNC@FITC@DEAC, to sensing pH, Cu<sup>2+</sup>, and pH/Cu<sup>2+</sup> excited by 405 nm light. The developed probe exhibited high selectivity and accuracy for independent determination of pH and Cu<sup>2+</sup> against reactive oxygen species (ROS), other metal ions, amino acids, and even copper-containing proteins. The AuNC-based inorganic–organic probe with good cell-permeability and high biocompatibility was eventually applied in monitoring both pH and Cu<sup>2+</sup> and in understanding the interplaying roles of Cu<sup>2+</sup> and pH in live cells by ratiometric multicolor fluorescent imaging

Topics: Biophysics, Biochemistry, Medicine, Cell Biology, Genetics, Molecular Biology, Biotechnology, Immunology, Cancer, Plant Biology, Environmental Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, Physical Sciences not elsewhere classified, DEAC, Single Probe, reference molecule, 405 nm light, FITC, signal transduction, fluorescein isothiocyanate, Ratiometric Fluorescence SignalsIt, emission peak, TPAASH, ROS, AuNC, Live Cells, reactive oxygen species, pH, 472 nm, gold cluster, Cu, interplaying roles, metal ions, 722 nm, 518 nm
Year: 2015
DOI identifier: 10.1021/acs.analchem.5b00628.s001
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Provided by: FigShare
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