问题描述：
英语翻译
Various transition-metal ions are crucial for the life of
organisms.1 Among these is the copper ion,which plays a
critical role as a catalytic cofactor for a variety of metalloenzymes,
including superoxide dismutase,cytochrome c
oxidase,and tyrosinase.However,under overloading conditions,
copper exhibits toxicity in that it causes neurodegenerative
diseases (e.g.,Alzheimer’s and Wilson’s diseases)
probably by its involvement in the production of reactive
oxygen species.2 Consequently,organisms tightly regulate
internal concentrations of copper.Owing to the Janus-faced
properties of copper in organisms,numerous efforts have
been undertaken to develop efficient and selective methods
to assess copper ions in cells and organisms.In addition,copper is a significant metal pollutant due to its widespread
use.The toxicity of copper ions for humans is rather low
compared to other heavy metals,but certain microorganisms
are affected by even submicromolar concentrations of Cu2+.3
Even though fluorescent probes for copper ion have been
extensively explored owing to biological significance of this
metal ion,4 there are still only a few examples of “off-on”
type sensors available in aqueous systems.5 Furthermore,
only a few ratiometric fluorescent probes for Cu2+ have been
found in the literature due the fluorescence quenching nature
of paramagnetic Cu2+,6 and most of them were working only
in pure organic solvents.Ratiometric fluorescent measurements
observe changes in the ratio of the intensities of the
emission at two wavelengths.Thus,ratiometric fluorescent
sensors have an important feature that they can be used to
evaluate the analyte concentration and provide built-in
correction for environmental effects.
Various transition-metal ions are crucial for the life of
organisms.1 Among these is the copper ion,which plays a
critical role as a catalytic cofactor for a variety of metalloenzymes,
including superoxide dismutase,cytochrome c
oxidase,and tyrosinase.However,under overloading conditions,
copper exhibits toxicity in that it causes neurodegenerative
diseases (e.g.,Alzheimer’s and Wilson’s diseases)
probably by its involvement in the production of reactive
oxygen species.2 Consequently,organisms tightly regulate
internal concentrations of copper.Owing to the Janus-faced
properties of copper in organisms,numerous efforts have
been undertaken to develop efficient and selective methods
to assess copper ions in cells and organisms.In addition,copper is a significant metal pollutant due to its widespread
use.The toxicity of copper ions for humans is rather low
compared to other heavy metals,but certain microorganisms
are affected by even submicromolar concentrations of Cu2+.3
Even though fluorescent probes for copper ion have been
extensively explored owing to biological significance of this
metal ion,4 there are still only a few examples of “off-on”
type sensors available in aqueous systems.5 Furthermore,
only a few ratiometric fluorescent probes for Cu2+ have been
found in the literature due the fluorescence quenching nature
of paramagnetic Cu2+,6 and most of them were working only
in pure organic solvents.Ratiometric fluorescent measurements
observe changes in the ratio of the intensities of the
emission at two wavelengths.Thus,ratiometric fluorescent
sensors have an important feature that they can be used to
evaluate the analyte concentration and provide built-in
correction for environmental effects.
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