title: Highly sensitive quinoline-based two-photon fluorescent probe for monitoring intracellular free zinc ions.
abstract: Zn(2+) plays vital roles in regulating physiological and pathological processes. A number of diseases are associated with the disruption of intracellular free Zn(2+) homeostasis, and the relationship is still uncovered. Thus, it is important to monitor intracellular free Zn(2+) ions in real time, which is still challenging due to the low content of intracellular free Zn(2+). In this work, we report on the design and synthesis of a new two-photon (2P) fluorescent probe, QZn, based on quinoline derivative for intracellular free Zn(2+). Theoretical calculations were carried out to rationalize the design. The probe displayed a moderate 2P action cross section value of 51 GM at 820 nm and up to 10-fold fluorescence enhancement upon Zn(2+) binding. The detection limit of Zn(2+) was 15.1 pM, which presented a pronounced sensitivity toward Zn(2+) and indicated that QZn would be competent for detecting the low-content intracellular Zn(2+). By using two-photon microscopy, QZn was capable of monitoring the fluctuation of intracellular free zinc ions in real time.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University , Wuhan, Hubei 430072, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Mao
authors.forename: Liang
authors.initials: L
authors.lastname: Hu
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Dong
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhong
authors.forename: Bi-Feng
authors.initials: BF
authors.lastname: Liu
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Liu
mesh_terms: D003593:Cytoplasm / Q000737:chemistry* / Q000648:ultrastructure; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D036641:Microscopy, Fluorescence, Multiphoton; D008958:Models, Molecular; D061848:Optical Imaging; D011804:Quinolines / Q000737:chemistry*; D015032:Zinc / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D011804:Quinolines; C037219:quinoline; D015032:Zinc