title: A novel chemosensor with visible light excitability for sensing Zn2+ in physiological medium and in HeLa cells.
abstract: In the present study a novel imine-hydrazone based fluorescent chemosensor () for efficient and selective sensing of Zn(2+) over other biologically important metal ions under physiological conditions is reported. An enhancement in fluorescence emission intensity of the developed probe with a red shift of ∼25 nm was observed for Zn(2+), whereas other metal ions failed to reveal any significant change in the emission spectra. Interestingly, the receptor functioned under completely physiological conditions (99.7% HEPES buffer) and has visible light excitability. Sensing of Zn(2+) was investigated in detail by absorption spectroscopy, emission spectroscopy, DFT calculation, (1)H-NMR titration experiment and ESI-MS experiment. The association constant between and Zn(2+) was found to be 5.58 × 10(5) M(-1). The receptor could detect as low as 69 ppb Zn(2+). Sensing of Zn(2+) is proposed through switch-on of intramolecular charge transfer (ICT) and chelation enhanced fluorescence (CHEF) processes after the introduction of Zn(2+) into the free ligand. The developed receptor was non-toxic and rendered intracellular sensing of Zn(2+) in HeLa cells through fluorescence imaging studies.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India. gdas@iitg.ernet.in.
authors.forename: Barun Kumar
authors.initials: BK
authors.lastname: Datta
authors.forename: Durairaj
authors.initials: D
authors.lastname: Thiyagarajan
authors.forename: Soham
authors.initials: S
authors.lastname: Samanta
authors.forename: Aiyagari
authors.initials: A
authors.lastname: Ramesh
authors.forename: Gopal
authors.initials: G
authors.lastname: Das
mesh_terms: D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010848:Picolinic Acids / Q000138:chemical synthesis; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization; D015032:Zinc / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D010848:Picolinic Acids; D015032:Zinc