title: Single Probe for Imaging and Biosensing of pH, Cu(2+) Ions, and pH/Cu(2+) in Live Cells with Ratiometric Fluorescence Signals.
abstract: 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(2+), 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(2+), and pH/Cu(2+) 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(2+), 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(2+), and pH/Cu(2+) excited by 405 nm light. The developed probe exhibited high selectivity and accuracy for independent determination of pH and Cu(2+) 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(2+) and in understanding the interplaying roles of Cu(2+) and pH in live cells by ratiometric multicolor fluorescent imaging.
authors.affiliation: †Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092, People's Republic of China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Han
authors.affiliation: †Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092, People's Republic of China.
authors.forename: Changqin
authors.initials: C
authors.lastname: Ding
authors.affiliation: †Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: †Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092, People's Republic of China.|‡Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, North Zhongshan Road 3663, Shanghai 200062, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Tian
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002470:Cell Survival; D003116:Color; D003300:Copper / Q000032:analysis* / Q000737:chemistry*; D003374:Coumarins / Q000737:chemistry; D015195:Drug Design; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry; D057054:Molecular Imaging / Q000379:methods*; D013050:Spectrometry, Fluorescence
chemical_list: D003374:Coumarins; D005456:Fluorescent Dyes; C088959:7-diethylaminocoumarin-3-carboxylic acid; D006046:Gold; D003300:Copper; D016650:Fluorescein-5-isothiocyanate