A novel ratiometric fluorescent probe for rapid detection of hydrogen peroxide in living cells

An indole-based near-infrared fluorescent "Turn-On" probe for H2O2: Selective detection and ultrasensitive imaging of zebrafish gallbladder

Fluorescent probes play essential roles in medical imaging, where the researchers can select one of many molecules to use to help monitor the status of living systems under investigation. To date, a few scaffolds that allow the in vivo detection of H2O2 are available only. Herein, we provide a highly sensitive and selective near-infrared fluorescent probe that detects H2O2 based on the ICT sensing mechanism. We report the first indole-incorporated fluorescent probe Indo-H2O2 that allows H2O2 detection with a LOD of 25.2 nM featuring a boronate group conjugated to an indole scaffold; the boronate cleaves upon reaction with H2O2. A 5-membered malononitrile derivative was incorporated; Indo-H2O2 has near-infrared (NIR) properties and the reaction time is low (∼25 min) compared to other related probes. Indo-H2O2 was successfully employed in both endogenous and exogenous imaging trials of H2O2 in living cells. Indo-H2O2 also allows the real-time monitoring of H2O2in vivo. It preferentially accesses the gallbladder of zebrafish. Our findings support Indo-H2O2 as a highly sensitive fluorescent NIR probe for detecting H2O2, and an idea to incorporate a central indole unit in future fluorescent probe designs.

Near-Infrared Fluorescence Probe for Indication of the Pathological Stages of Wound Healing Process and Its Clinical Application

Chronic wound healing is one of the most complicated biological processes in human life, which is also a serious challenge for human health. During the healing process, multiple biological pathways are activated, and various kinds of reactive oxygen species participate in this process. Hydrogen peroxide (H2O2) involves in chronic wounds and its concentration is fluctuated in different pathological stages during the wound healing process. Therefore, H2O2 may be recognized as a powerful biomarker to indicate the wound healing process. However, the pathological roles of H2O2 cannot be fully understood yet. Herein, we proposed a near-infrared fluorescent probe DCM-H2O2 for highly sensitive and rapid detection of H2O2 in living cells and scald and incision wound mice models. DCM-H2O2 exhibited a low detection limit and high specificity with low cytotoxicity for H2O2, which had great potential for its application in vivo. The probe was successfully utilized to monitor the fluctuation of endogenous H2O2 in the proliferation process of human immortalized epidermal (HACAT) cells, which confirmed that H2O2 participated in the cells' proliferation activity through a growth factor signaling pathway. In the scald and incision wound mice models, H2O2 concentration fluctuations at different pathological stages during the wound healing process could be obtained by in vivo fluorescence imaging. Finally, H2O2 concentrations in different stages of human diabetic foot tissues were also confirmed by the proposed probe. We expect that H2O2 could be a sensitive biomarker to indicate the wound healing process.

Pentafluorobenzene: Promising Applications in Diagnostics and Therapeutics

Pentafluorobenzene (PFB) represents a class of aromatic fluorine compounds employed exclusively across a spectrum of chemical and biological applications. PFBs are credited with developing various chemical synthesis techniques, networks and biopolymers, bioactive materials, and targeted drug delivery systems. The first part of this review delves into recent developments in PFB-derived molecules for diagnostic purposes. In the latter segment, PFB's role in the domain of theragnostic applications is discussed. The review elucidates different mechanisms and interaction strategies applied in leveraging PFBs to formulate diagnostic and theragnostic tools, substantiated by proper examples. The utilization of PFBs emerges as an enabler, facilitating manifold reactions, improving materials' properties, and even opening avenues for explorative research.

A ratiometric ESIPT fluorescent probe for detection of anticancer-associated H2O2 level in vitro and in vivo

ROS is a significant factor in the cancer treatment mechanism. The monitoring anticancer-associated H₂O₂ level plays a vital role in the anticancer mechanistic exploration in pathology and physiology. Herein we synthesized a ratiometric fluorescent probe (HBQ-L) to detect and image H₂O₂ based on excited-state intramolecular proton transfer. HBQ-L had a high sensitivity (231-fold) with a low detection limit (28.5 nM) for monitoring H₂O₂ in solution. HBQ-L showed good mitochondrial-targeting and successfully detected both exo-/endogenous H₂O₂ in A549 cells. Furthermore, HBQ-L was used to ratiometric monitor H₂O₂ level in anticancer reagent DOX-treated cells or zebrafish. Importantly, it was employed to access the monitoring H₂O₂ in the A549 tumor-bearing mice.

Facile preparation of Cu-doped carbon dots for naked-eye discrimination of phenylenediamine isomers and highly sensitive ratiometric fluorescent detection of H2O2

Changing a detection analyte into a colored material is a key challenge for visual discrimination of isomers. In this work, a novel fluorescent probe incorporating Cu-doped carbon dots (Cu-CDs), for the first time, was developed for naked-eye discrimination of phenylenediamine isomers and highly sensitive ratiometric fluorescence detection of H₂O₂. In this strategy, Cu-CDs were synthesized by a facile hydrothermal approach using citric acid, formamide, and CuCl₂ as reactants. The prepared Cu-CDs exhibited outstanding peroxidase-like activity and stability. Consequently, a chemosensor platform based on Cu-CDs was constructed to enable naked-eye discrimination of phenylenediamine isomers through the H₂O₂-mediated oxidation reaction. Moreover, a Cu-CDs-based ratiometric fluorescence sensor was proposed as a means to sensitively detect H₂O₂ with a detection limit of 5.0 nM. The sensor was further employed for monitoring H₂O₂ in human serum, indicating its potential applications in other biologically related study.