A fast-response two-photon fluorescent probe for imaging endogenous H2O2 in living cells and tissues

A new near-infrared fluorescence probe synthesized from IR-783 for detection and bioimaging of hydrogen peroxide in vitro and in vivo

A new near-infrared fluorescence probe was developed and synthesized for detection of hydrogen peroxide (H₂O₂) in vitro and in vivo. Synthesized from IR-783, the probe DBIS was designed to connect 4-(Bromomethyl)benzeneboronic acid pinacol ester as the recognizing moiety to the stable hemicyanine skeleton. Reaction of probe DBIS with H₂O₂ would result in the oxidation of phenylboronic acid pinacol ester, and thereby release the near-infrared fluorophore HXIS. The background signal of probe DBIS is very low, which is necessary for sensitive detection. Compared with the existing probes for detecting H₂O₂, the proposed probe DBIS shows excellent optical performance in vitro and in vivo, high selectivity, high sensitivity and good water solubility, as well as near-infrared fluorescence emission 708 nm, with a low detection limit of 0.12 μM. Furthermore, probe DBIS is low cytotoxic, cell membrane permeable, and its applicability has been shown to visualize endogenous H₂O₂ in mice. In addition, it is the first time that paper chips have been used as carrier to detect H₂O₂ through fluorescence signals instead of the traditional liquid phase detection mode of fluorescent probes. These superior characteristics of the probe make it have great application potential in biological systems or in vivo related research.

Design of a facile fluorescent probe with a large Stokes shift for hydrogen peroxide imaging in vitro and in vivo

By modifying 4'‑hydroxybiphenyl‑4‑carbonitrile (BPN-OH) with 2‑(4‑(bromo‑methyl)phenyl)‑4,4,5,5‑tetramethyl‑1,3,2‑dioxaborolane group, a facile fluorescent probe, BPN-TOB, for sensitively tracing H₂O₂ was designed and synthesized. BPN-TOB displayed a low detection limit (67 nM), fast response time (10 min), low cytotoxicity, a mega Stokes shift (170 nm) and a remarkable fluorescence enhancement (72-fold) in the detection of H₂O₂. Additionally, probe BPN-TOB could monitor exogenous and endogenous H₂O₂ in living MGC-803 cells (human gastric cancer cells) and RAW264.7 cells (leukemia cellsin mouse macrophage). In particular, this probe BPN-TOB was successfully utilized for imaging H₂O₂ in zebrafish.

Design of a Nile red-based NIR fluorescent probe for the detection of hydrogen peroxide in living cells

In this article, a novel fluorescent probe (NRBE) for detecting H₂O₂ was developed using benzyl boronic ester as the H₂O₂-recognized group and Nile red as the matrix. The probe has several advantages, such as good selectivity, high sensitivity (LOD = 75 nM), good water solubility and emission in the near-infrared region (ex/em:585/670 nm). With the NRBE probe, the endogenous H₂O₂ in human hepatocellular carcinoma cells BEL-7402, was detected, and the H₂O₂ generated during the ischemia-reperfusion of the cells was imaged. These results show that NRBE can be applied for real-time detection of H₂O₂ in biological systems.

Research progress in the development of organic small molecule fluorescent probes for detecting H2O2

Hydrogen peroxide (H2O2), as an important signaling molecule during biological metabolism, is a key member of the reactive oxygen species (ROS) family. The excess of H2O2 will lead to oxidative stress, which is a crucial factor in the production of various ROS-related diseases. In order to study the diverse biological roles of H2O2 in cells and animal tissues, many methods have been developed to detect H2O2. Recently, fluorescence imaging has attracted more and more attention because of its high sensitivity, simple operation, experimental feasibility, and real-time online monitoring. Based on the response group, this study will review the research progress on hydrogen peroxide and summarizes the mechanisms, actualities and prospects of fluorescent probes for H2O2.

Fluorescent Imaging for Cysteine Detection In Vivo with High Selectivity

As an essential amino acid, cysteine is involved in various biosynthetic and metabolic processes, such as protein synthesis, hormone synthesis, and redox homeostatic maintenance. Inordinate cysteine levels are often associated with serious diseases. Thus, designing and synthesizing a novel fluorescent probe for determining the concentration of cellular cysteine, which could indirectly monitor the prevalence of these diseases, is essential. We developed a florescence probe P-Cy with good sensitivity for cysteine detection in vivo. P-Cy only exhibited good response toward cysteine but did not show response toward other biothiols, such as homocysteine (Hcy) and glutathione (GSH). In this study, we used P-Cy by successfully imaging cellular endogenous and exogenous cysteine levels. Furthermore, P-Cy was also performed in mice to detect cysteine level, indicating that P-Cy is a powerful tool for cysteine detection in situ.