pH-Dependent Fluorescent Probe That Can Be Tuned for Cysteine or Homocysteine

Abstract

The very close structural similarities between cysteine and homocysteine present a great challenge to achieve their selective detection using regular fluorescent probes, limiting the biological and pathological studies of these two amino thiols. A coumarin-based fluorescent probe was designed featuring pH-promoted distinct turn-on followed by ratiometric fluorescence responses for Cys and turn-on fluorescence response for Hcy through two different reaction paths. These specific responses demonstrate the activity differences between Cys and Hcy qualitatively for the first time. The probe could also be used for Cys and Hcy imaging in living cells.

Visual Discrimination of Homocysteine from Cysteine through Selective Fluorescent Gel Formation

“…In contrast to Cys, a few methods enabled the selective discrimination of Hcy. They were based on chemical reactions and aggregation of gold nanoparticles . It is still necessary to develop a reliable strategy for distinguishing Hcy from Cys.…”

Naked-eye Detection of Hg2+ in Practical Applications Using a Highly Selective and Sensitive Fluorescent Probe

“…The general synthesis route of DAC-Hg is outlined in Scheme 1. Intermediates B and DAC-CHO were readily prepared utilizing a literature procedure, 37,38 and then converted into dithioacetals DAC-Hg through a straightforward reaction with 1,3-dimercaptopropane. The structure of DAC-CHO and the probe DAC-Hg were both fully confirmed by 1 H NMR, 13 C NMR, HR-MS and FT-IR spectra (Figs.…”

A Near-Infrared Ratiometric Fluorescent Probe for Highly Selective Recognition and Bioimaging of Cysteine

“…Additionally, the ratiometric fluorescent probes could provide an inherent reliability originating from its effective self-calibration advantage by monitoring two well-resolved emissions (Kikuchi et al, 2004; Demchenko, 2010; Lee et al, 2015). Although a number of fluorescent probes for Cys detection and imaging have been reported, most of them could not discriminate Cys from Hcy/GSH due to their similar molecular structures and reactivity (Chen et al, 2017, 2018; Li et al, 2017; Liu X. et al, 2017; Nawimanage et al, 2017; Wang F. et al, 2017; Wang Q. et al, 2017, 2018a; Wu et al, 2017; Yin et al, 2017; Yue et al, 2017a,b; Zhang et al, 2017, 2018a,b; Hou et al, 2018; Kim et al, 2018; Ren et al, 2018; Song et al, 2018; Tian et al, 2018; Wang et al, 2018b; Wang J. et al, 2018; Wang L. et al, 2018; Sheng et al, 2019). Several ratiometric fluorescent probes for Cys have been developed (Lv et al, 2014; Feng et al, 2017; Liu G. et al, 2017; Wang F. et al, 2017; Wang L. et al, 2018 Wu et al, 2018; Yue et al, 2018; Zhu et al, 2018), but only a few of them showed the fluorescence emission in NIR region (Feng et al, 2017; Zhu et al, 2018).…”