A selective, nontoxic, OFF-ON fluorescent molecular sensor based on 8-hydroxyquinoline for probing Cd(2+) in living cells.
In spite of the fact that cadmium(II) has been recognized as a highly toxic element and that excessive exposure to this metal ion has been reported to have many adverse effects on human health, very few selective and specific fluorescent probes are available for imaging Cd(2+) in living cells. Herein, we report the spectroscopic and photochemical characterization of 5-(5-chloro-8-hydroxyquinolinylmethyl)-2,8-dithia-5-aza-2,6-pyridinophane (L) as a fluorescent sensor for the selective imaging of Cd(2+) in living cells. In particular, the response of L to Cd(2+) was first assessed in aqueous solutions, sodium dodecyl sulfate micelles, and liposomes, and subsequently in living cells by fluorescence microscopy techniques. Cytofluorimetric analyses of leukemic HL-60 cells loaded with L also allowed evaluation of the toxicity of the probe and the selective analysis of its intracellular fluorescence in the presence of Cd(2+). Furthermore, the 1:1 complex species [Cd(L)H(2)O](2+) responsible for the OFF-ON chelation enhancement of fluorescence (CHEF) effect on L was structurally characterized; time-dependent DFT calculations allowed the prediction of theoretical excitations, which were comparable with the experimental ones.
Mameli
Marta
M
Dipartimento di Chimica Inorganica ed Analitica, S.S. 554 Bivio per Sestu, Università degli Studi di Cagliari, 09042 Monserrato, CA, Italy.
Aragoni
M Carla
MC
Arca
Massimiliano
M
Caltagirone
Claudia
C
Demartin
Francesco
F
Farruggia
Giovanna
G
De Filippo
Greta
G
Devillanova
Francesco A
FA
Garau
Alessandra
A
Isaia
Francesco
F
Lippolis
Vito
V
Murgia
Sergio
S
Prodi
Luca
L
Pintus
Anna
A
Zaccheroni
Nelsi
N
D000818:Animals; D019556:COS Cells; D002104:Cadmium / Q000737:chemistry* / Q000633:toxicity; D002460:Cell Line; D002614:Chelating Agents / Q000737:chemistry; D002522:Chlorocebus aethiops; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000737:chemistry*; D018922:HL-60 Cells; D006801:Humans; D008081:Liposomes / Q000737:chemistry; D008823:Micelles; D008856:Microscopy, Fluorescence; D008968:Molecular Conformation; D015125:Oxyquinoline / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000737:chemistry; D013816:Thermodynamics
D002614:Chelating Agents; D056831:Coordination Complexes; D005456:Fluorescent Dyes; D008081:Liposomes; D008823:Micelles; D017319:Photosensitizing Agents; D002104:Cadmium; D015125:Oxyquinoline