Dual-Ratiometric Fluorescent Probe for H2O2 and HClO in Living Cells and Zebrafish and Application in Alcoholic Liver Injury Monitoring

A bifunctional fluorescent probe for dual-channel detection of H2O2 and HOCl in living cells

Hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) are critical reactive oxygen species (ROS) that play significant roles in regulating oxidative stress, closely tied to various human diseases. However, investigating their interplay within living cells has been challenging due to the lack of effective tools for simultaneous discrimination. Herein, we present a bifunctional fluorescent probe, PTZ-H-H, capable of simultaneously detecting H2O2 and HOCl in living cells via two distinct fluorescence channels. PTZ-H-H exhibits selective and sensitive responses, emitting red fluorescence in the presence of H2O2 and green fluorescence in response to HOCl, with detection limits of 386 nM and 16.8 nM, respectively. The probe was successfully applied in living cells, enabling real-time monitoring of intracellular H2O2 and HOCl. This study demonstrates the potential of PTZ-H-H as a powerful tool for exploring the dynamic roles of H2O2 and HOCl in various physiological and pathological processes.

Novel NIR fluorescent probe based on BODIPY for diagnosis and treatment evaluation of alcoholic liver disease via visualizing HClO fluctuation

Alcoholic liver disease (ALD) is gradually becoming common due to the increasing number of drinkers worldwide, which is a serious threat to human physical and mental health. In the process of ALD, it is often accompanied by the occurrence of inflammation, which induce high expression of reactive oxygen species including HClO. In this work, we successfully fabricated a NIR fluorescent probe BDP-ENE-Fur-HClO for real-time imaging alcoholic liver disease via tracing HClO. The probe displayed good sensitivity and specificity, rapid recognition speed and NIR emitting (700 nm) for detection of HClO in vitro. Based on the remarkable performances, probe was capable of tracing endogenous/exogenous HClO in living cells without interference from other ROS as well as in ALD cell model. Additionally, probe could monitor the exogenous HClO in normal mice and high expression of HClO in the peritonitis mice, that accomplishing the diagnosis of inflammation. What's more, one simulated hazardous drinking ALD mice model and simulated excessive drinking (a type of alcohol use disorder) ALD mice model were developed, probe could image the alcoholic liver injury of mice by monitoring the HClO fluctuation in ALD mice, which affording a valid instrument for the diagnosis of ALD. Ultimately, after hepatoprotective drug administrating to the models, probe could triumphantly evaluate the treatment effect of drug on ALD.

A colorimetric and ratiometric fluorescent probe of hypochlorous acid and its bio-imaging application

A new ratiometric and colorimetric fluorescent probe HTD was synthesized based on the reaction of 4-aminophenyl boronic acid pinacol ester and 4-(3-formyl-4-hydroxyphenyl) benzonitrile. The probe exhibited a unique fluorescence response to hypochlorous acid and had good anti-interference performance in the presence of other interference. When HTD met the NaClO, the light orange fluorescence was changed to green with the blue-shifted emission wavelength from 550 to 500 nm. Moreover, the absorbance of HTD's UV-vis at 300 nm and 375 nm decreased in the presence of NaClO. The limit of detection was 1.83 × 10-7 M and 2.96 × 10-6 M based on the fluorescence and UV-vis titration data. NMR, HRMS, and IR spectra suggested that the possible sensing mechanism of HTD to NaClO was the formation of initial compound 4-(3-formyl-4-hydroxyphenyl) benzonitrile due to the oxidation of hypochlorous acid in aqueous solution. The portable test strips were obtained, and the real water sample test reached good results with spiking recoveries among 92.00% ~ 103.25%. Finally, endogenous hypochlorous acid produced by LPS and PMA was successfully detected by HTD in living mice using in situ fluorescence bioimaging.

A red turn-on fluorescent probe reveals elevated H2O2 in cell anesthesia

Cognitive dysfunction has become an important central nervous system (CNS)-related adverse reaction of intravenous anesthetics. Therefore, to further understand the role of H2O2, a potential marker of cognitive dysfunction, we constructed a fluorescent probe (LJ-1), which could specifically enable real-time detection of H2O2 in cells during anesthesia.

Rapid-response near-infrared fluorescence probe for colorimetric detection of HClO and its applications in environmental monitoring and biological imaging

As a crucial endogenous reactive oxygen species, hypochlorous acid (HClO) plays an indispensable role in numerous physiological and pathological processes. Additionally, it serves as a biomarker closely associated with inflammation and liver injury. The utilization of near-infrared fluorescence probes has surged in recent years for live biological imaging, owing to their minimal tissue damage and potent tissue penetration capabilities. In this work, a novel near-infrared fluorescence probe MB-HPD was synthesized to sensitively detect HClO. Probe MB-HPD exhibits remarkable selectivity, high sensitivity (14.3 nM), and rapid response towards HClO (20 s). Probe MB-HPD has demonstrated successful application in the imaging of HClO within cells and zebrafish. Remarkably, it has proven to be effective for detecting HClO within environmental samples, as well as imaging HClO in mice models of arthritis and APAP-induced liver injury. These findings indicate the broad applicability of probe MB-HPD, offering a promising avenue for designing highly selective near-infrared fluorescence probes suitable for real-time HClO monitoring.

Dual NIR-channel fluorescent probe for detecting ONOO- in vitro and vivo

As one of endogenous reactive oxygen species (ROS), peroxynitrite (ONOO-) performs various functions in both pathological and physiological mechanisms. In this work, an optical and near-infrared (NIR) fluorescent probe (NX), which based on 3-dihydro-1H-xanthene and 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF) group was designed and prepared to detect ONOO-. This probe revealed an obvious optical and a fluorescent response when ONOO- was present and it exhibited higher selectivity over other ROS. Especially, the dual NIR fluorescence changes at 660 and 800 nm allowed quantitative detection of ONOO- in the range of 15-40 μM, and the detection limit was 82 nM. Finally, the probe was effectively employed to visualize exogenous and endogenous ONOO- in HepG2 cells and zebrafish, respectively. All the results indicated the dual NIR-channel probe could serve as a potent detecting tools in studying ONOO- in vitro and in vivo.

Ex Tenebris Lux: Illuminating Reactive Oxygen and Nitrogen Species with Small Molecule Probes

Reactive oxygen and nitrogen species are small reactive molecules derived from elements in the air─oxygen and nitrogen. They are produced in biological systems to mediate fundamental aspects of cellular signaling but must be very tightly balanced to prevent indiscriminate damage to biological molecules. Small molecule probes can transmute the specific nature of each reactive oxygen and nitrogen species into an observable luminescent signal (or even an acoustic wave) to offer sensitive and selective imaging in living cells and whole animals. This review focuses specifically on small molecule probes for superoxide, hydrogen peroxide, hypochlorite, nitric oxide, and peroxynitrite that provide a luminescent or photoacoustic signal. Important background information on general photophysical phenomena, common probe designs, mechanisms, and imaging modalities will be provided, and then, probes for each analyte will be thoroughly evaluated. A discussion of the successes of the field will be presented, followed by recommendations for improvement and a future outlook of emerging trends. Our objectives are to provide an informative, useful, and thorough field guide to small molecule probes for reactive oxygen and nitrogen species as well as important context to compare the ecosystem of chemistries and molecular scaffolds that has manifested within the field.

Novel mycophenolic acid precursor-based fluorescent probe for intracellular H2O2 detection in living cells and Daphnia magna and Zebrafish model systems

Innovative for the scientific community and attracting attention in the extensive biomedical field are novel compact organic chemosensing systems built upon unique core molecular frameworks. These systems may demonstrate customized responses and may be adaptable to analytes, showing promise for potential in vivo applications. Our recent investigation focuses on a precursor of Mycophenolic acid, resulting in the development of LBM (LOD = 13 nM) - a specialized probe selective for H2O2. This paper details the synthesis, characterization, and thorough biological assessments of LBM. Notably, we conducted experiments involving living cells, daphnia, and zebrafish models, utilizing microscopy techniques to determine probe nontoxicity and discern distinct patterns of probe localization. Localization involved the distribution of the probe in the Zebrafish model within the gut, esophagus, and muscles of the antennae.

Design, synthesis and application of dual-channel fluorescent probes for ratiometric detection of HClO and H2S based on phenothiazine coumarins

The ubiquity of diverse material entities in environmental matrices renders the deployment of unifunctional fluorescent indicators inadequate. Consequently, this study introduces a ratiometric dual-emission fluorescent sensor (Probe CP), synthesized by conjugating phenothiazine coumarin to hydroxycoumarin through a piperazine linker for concurrent detection of HClO and H2S. Upon interaction with HClO, the phenothiazine unit's sulfur atom undergoes oxidation to sulfoxide, facilitating a shift from red to green fluorescence in a ratiometric manner. Concurrently, at the opposite terminus of Probe CP, 2,4-dinitroanisole serves as the reactive moiety for H2S recognition; it restores the blue emission characteristic of 7-hydroxycoumarin while maintaining the red fluorescence emanating from phenothiazine coumarin as an internal standard for ratio-based assessment. Exhibiting elevated specificity and sensitivity coupled with minimal detection thresholds (0.0506 μM for HClO and 1.7292 μM for H2S) alongside rapid equilibration periods (3 min for HClO and half an hour for H2S), this sensor was efficaciously employed in cellular environments and within zebrafish models as well as imaging applications pertaining to alcohol-induced hepatic injury in murine subjects.

Dual-Emissive Detection of ATP and Hypochlorite Ions for Monitoring Inflammation-Driven Liver Injury In Vitro and In Vivo

Reactive oxygen species play a pivotal role in liver disease, contributing to severe liver damage and chronic inflammation. In liver injury driven by inflammation, adenosine-5'-triphosphate (ATP) and hypochlorite ion (ClO-) emerge as novel biomarkers, reflecting mitochondrial dysfunction and amplified oxidative stress, respectively. However, the dynamic fluctuations of ATP and ClO- in hepatocytes and mouse livers remain unclear, and multidetection techniques for these biomarkers are yet to be developed. This study presents RATP-NClO, a dual-channel fluorescent bioprobe capable of synchronously detecting ATP and ClO- ions. RATP-NClO exhibits excellent selectivity and sensitivity for ATP and ClO- ions, demonstrating a dual-channel fluorescence response in a murine hepatocyte cell line. Upon intravenous administration, RATP-NClO reveals synchronized ATP depletion and ClO- amplification in the livers of mice with experimental metabolic dysfunction-associated steatohepatitis (MASH). Through a comprehensive analysis of the principal mechanism of the developed bioprobe and the verification of its reliable detection ability in both in vitro and in vivo settings, we propose it as a unique tool for monitoring changes in intracellular ATP and ClO- level. These findings underscore its potential for practical image-based monitoring and functional phenotyping of MASH pathogenesis.

Hydrogen peroxide fluorescent probe-monitored butyric acid inhibition of the ferroptosis process

Short-chain fatty acids, such as butyrate, play pivotal roles in various physiological processes within the human body. Recent advances in understanding cell death pathways, specifically ferroptosis, have unveiled unique opportunities for therapeutic development. Ferroptosis is linked to iron accumulation and oxidative stress, whereas butyrate has emerged as a cellular protector against oxidative stress, potentially inhibiting ferroptosis. Hydrogen peroxide (H2 O2 ) is a key player in oxidative stress, and its monitoring has gained significance in disease mechanisms. We present an innovative fluorescent probe, HOP, capable of dynamically tracking intracellular H2 O2 levels, enabling spatial and temporal visualization. The probe exhibits high accuracy (limit of detection = 0.14 μM) and sensitivity, paving the way for disease diagnosis and treatment innovations. Importantly, HOP displayed minimal toxicity, making it suitable for cellular applications. Cellular imaging experiments demonstrated its ability to penetrate cells and monitor intracellular H2 O2 levels accurately. The HOP probe confirmed H2 O2 as a critical marker in ferroptosis. Our innovative HOP provides a powerful tool for tracking intracellular H2 O2 levels and offers insights into the modulation of ferroptosis, potentially opening new avenues for disease research and therapeutic interventions.

Recent theranostic applications of hydrogen peroxide-responsive nanomaterials for multiple diseases

It is well established that hydrogen peroxide (H2O2) is associated with the initiation and progression of many diseases. With the rapid development of nanotechnology, the diagnosis and treatment of those diseases could be realized through a variety of H2O2-responsive nanomaterials. In order to broaden the application prospects of H2O2-responsive nanomaterials and promote their development, understanding and summarizing the design and application fields of such materials has attracted much attention. This review provides a comprehensive summary of the types of H2O2-responsive nanomaterials including organic, inorganic and organic-inorganic hybrids in recent years, and focused on their specific design and applications. Based on the type of disease, such as tumors, bacteria, dental diseases, inflammation, cardiovascular diseases, bone injury and so on, key examples for above disease imaging diagnosis and therapy strategies are introduced. In addition, current challenges and the outlook of H2O2-responsive nanomaterials are also discussed. This review aims to stimulate the potential of H2O2-responsive nanomaterials and provide new application ideas for various functional nanomaterials related to H2O2.