Fluorescent zinc sensor with minimized proton-induced interferences

Photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions

Ji Eon Kwon, Sumin Lee, Youngmin You, Kyung Hwa Baek, Kei Ohkubo, Jaeheung Cho, Shunichi Fukuzumi, Injae Shin, Soo Young Park, Wonwoo Nam

Research output: Contribution to journalArticle

104 Citations (Scopus)

Abstract

A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'- naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a Kd value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

Original languageEnglish
Pages (from-to)8760-8774
Number of pages15
JournalInorganic Chemistry
Volume51
Issue number16
DOIs
Publication statusPublished - 2012 Aug 20

Fingerprint

Benzoxazoles
Protons
Zinc
zinc
Fluorescence
Ions
interference
fluorescence
protons
sensors
Sensors
ions
probes
Deprotonation
Density functional theory
Metal ions
Electrons
metal ions
electron transfer
density functional theory

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Kwon, Ji Eon ; Lee, Sumin ; You, Youngmin ; Baek, Kyung Hwa ; Ohkubo, Kei ; Cho, Jaeheung ; Fukuzumi, Shunichi ; Shin, Injae ; Park, Soo Young ; Nam, Wonwoo. / Fluorescent zinc sensor with minimized proton-induced interferences : Photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions. In: Inorganic Chemistry. 2012 ; Vol. 51, No. 16. pp. 8760-8774.
@article{8869d42f65564078861b0de0b66b9bdf,
title = "Fluorescent zinc sensor with minimized proton-induced interferences: Photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions",
abstract = "A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'- naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a Kd value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.",
author = "Kwon, {Ji Eon} and Sumin Lee and Youngmin You and Baek, {Kyung Hwa} and Kei Ohkubo and Jaeheung Cho and Shunichi Fukuzumi and Injae Shin and Park, {Soo Young} and Wonwoo Nam",
year = "2012",
month = "8",
day = "20",
doi = "10.1021/ic300476e",
language = "English",
volume = "51",
pages = "8760--8774",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "16",

}

Fluorescent zinc sensor with minimized proton-induced interferences : Photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions. / Kwon, Ji Eon; Lee, Sumin; You, Youngmin; Baek, Kyung Hwa; Ohkubo, Kei; Cho, Jaeheung; Fukuzumi, Shunichi; Shin, Injae; Park, Soo Young; Nam, Wonwoo.

In: Inorganic Chemistry, Vol. 51, No. 16, 20.08.2012, p. 8760-8774.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Fluorescent zinc sensor with minimized proton-induced interferences

T2 - Photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions

AU - Kwon, Ji Eon

AU - Lee, Sumin

AU - You, Youngmin

AU - Baek, Kyung Hwa

AU - Ohkubo, Kei

AU - Cho, Jaeheung

AU - Fukuzumi, Shunichi

AU - Shin, Injae

AU - Park, Soo Young

AU - Nam, Wonwoo

PY - 2012/8/20

Y1 - 2012/8/20

N2 - A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'- naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a Kd value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

AB - A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'- naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a Kd value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

UR - http://www.scopus.com/inward/record.url?scp=84865261924&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84865261924&partnerID=8YFLogxK

U2 - 10.1021/ic300476e

DO - 10.1021/ic300476e

M3 - Article

VL - 51

SP - 8760

EP - 8774

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 16

ER -