Colorimetric and NIR Fluorescence Probe with Multiple Binding Sites for Distinguishing Detection of Cys/Hcy and GSH in Vivo

Abstract

Although some progress has been made in distinguishing the detection of biothiols, NIR biothiol fluorescent probes for simultaneously distinguishing detection of Cys, Hcy, and GSH in vivo have not been reported. The design of these probes involves the introduction of NIR fluorophores and multiple binding sites; thus, the integrated design of probes remains a challenge. Although Cys, Hcy, and GSH have common functional groups, a sulfydryl group and an amino group, due to their differences in spatial structure, they may react with multiple binding site probes to produce different reaction products in different bonding mechanisms, resulting in different colors and fluorescent signal changes of the system. Therefore, multiple binding site fluorescent probes can realize their discrimination detection. For an NIR fluorescent probe, it is easier to realize in vivo imaging to promote the research of biothiols in clinical diagnosis. In our work, not only were multiple binding sites constructed in the compound but also NIR fluorophores were introduced. This enables the probe to not only efficiently distinguish detection of Cys/Hcy and GSH but also achieve fluorescence imaging in vivo. We believe this result is a milestone in the discrimination detection of biothiols.

Reduced Thiol Compounds – Induced Biosensing, Bioimaging Analysis and Targeted Delivery

“…Yin's research team proposed a near‐infrared fluorescent probe, which has a specific recognition site for GSH/Cys/Hcy and can respond to three substances at the same time and produce different signals, thus distinguishing different kinds of RTCs (Figure 9). [46] The probe has three potential reaction sites: the reactive chlorine atom in site 1, the α and β‐unsaturated bonds of Michael acceptor in site 2, and the unsaturated bond of indole moiety in site 3. The chlorine atom in site 1 can react with Cys/Hcy and GSH to form three kinds of compounds with different structures (defined as 1a, 2a and 3a).…”

“…Simultaneous sensing of Cys, Hcy, and GSH, based on three potential reaction sites of probe [46] . Reprinted with permission from Ref.…”

A Fast Dual-responsive OFF-ON Fluorescent Probe for Cysteine and Glutathione without Interference from Homocysteine

“…To simultaneously detect more than one biothiol, researchers take great efforts to afford multi-binding-site probes. [16][17][18] These multi-binding sites probes assemble two or three reacting sites in one molecule according to the specific structure of Cys/Hcy/GSH, but they are all complicated to synthesize.…”

A GSH Fluorescent Probe with a Large Stokes Shift and Its Application in Living Cells

“…Most organic fluorescent probes which were applied to detect GSH showed high nucleophilicity, which were named "reaction based probes". Reaction based probes are mainly related to cleavage of sulfonate ester [20], acryloyl ester [7] and aryl substitution reactions [5,21,22], disulfide bond cleavage [23] and cyclization [24], and Michael additions [25,26]. As organic molecules are easy to modify, fluorescent probes with different emission wavelengths were synthesized and applied to cell imaging.…”