Detection Of Hydroxyl Radicals Research Articles

Dual-Activated Photoacoustic Probe for Reliably Detecting Hydroxyl Radical in Ischemic Cardiovascular Disease in Mouse and Human Samples.

Cardiovascular disease (CVD) is a chronic disease characterized by the accumulation of lipids and fibrous tissue within the arterial walls, potentially leading to vascular obstruction and an increased risk of heart disease and stroke. Hydroxyl radicals play a significant role in the formation and progression of CVD as they can instigate lipid peroxidation, resulting in cellular damage and inflammatory responses. However, precisely detecting hydroxyl radicals in CVD lesions presents significant challenges due to their high reactivity and short lifespan. Herein, we present the development and application of a novel activatable optical probe, Cy-OH-LP, designed to detect hydroxyl radicals in lipid-rich environments specifically. Built on the Cy7 molecular skeleton, Cy-OH-LP exhibits near-infrared absorption and fluorescence characteristics, and its specific response to hydroxyl radicals enables a turn-on signal in both photoacoustic and fluorescence spectra. The probe demonstrated excellent selectivity and stability in various tests. Furthermore, Cy-OH-LP was successfully applied in an in vivo model to detect hydroxyl radicals in mouse models, providing a potential tool for diagnosing and monitoring AS. The biosafety of Cy-OH-LP was also verified, showing low cytotoxicity and no significant organ damage in mice. The findings suggest that Cy-OH-LP is a promising tool for the specific detection of hydroxyl radicals in lipid-rich environments, providing new possibilities for research and clinical applications in the field of oxidative stress-related diseases.

Oxidative stability of chelated Sn(II)(aq) at neutral pH: The critical role of NO3- ions.

Tin(II) compounds are versatile materials with applications across fields such as catalysis, diagnostic imaging, and therapeutic drugs. However, oxidative stabilization of Sn(II) has remained an unresolved challenge as its reactivity with water and dioxygen results in loss of functionality, limiting technological advancement. Approaches to slow Sn(II) oxidation with chelating ligands or sacrificial electron donors have yielded only moderate improvements. We demonstrate here that the addition of nitrate to pyrophosphate-chelated Sn(II)(aq) suppresses Sn(II) oxidation in water across a broad pH range. Evidence of hydroxyl radical concentration reduction and detection of a radical nitrogen species that only forms in the presence of chelated Sn(II) point to a radical-based reaction mechanism. While this chemistry can be broadly applied, we present that this approach maintains Sn(II)'s antibacterial and anti-inflammatory efficacies as an example of sustained oral chemotherapeutic functionality.

Copper-PANI-graphite HB2 composite for eco-friendly efficient degradation of textile dyes: Advancements in wastewater treatment enhanced by solar radiation

This research aimed to assess the potential of Cu50PANI@UG composite for sunlight drive photocatalytic dye degradation, targeting specifically Thymol Blue (TB) and Black NT (BNT) dyes and their mixture (DM). The Cu50PANI@UG composite was successfully synthesized via electropolymerization in acetonitrile/sulfuric acid mixture under atmospheric conditions. Photocatalytic experiments were conducted by exposing aqueous dye solutions to sunlight. N,N-dimethyl-p-nitrosoaniline (RNO) served as a molecular probe for detecting hydroxyl radicals (•OH). Additionally, experiments capturing free radicals were performed to identify active components, with a concomitant proposal of plausible degradation reaction mechanism for the Photo-Fenton-Like degradation into the Cu50PANI@UG composite + H2O2 + hv reaction system. Various operating parameters affecting dye degradation were evaluated, including catalyst dosage (from 0.27 to 0.67 g L−1), H2O2 concentration (from 16 to 64 mM), pH (from 3.0 to 9.0), and dye concentration (from 25 to 100 mg L−1). Optimization of key parameters such as pH, catalyst dosage, and H2O2 concentration was conducted. The highest degradation efficiency, ca. 100% of DM dye, was achieved within 35 min under optimized conditions, using Cu50PANI@UG composite as a catalytic precursor. These conditions were determined as follows: Catalyst dosage = 0.67 g L−1, pH = 3.0–6.0, H2O2 = 32–64 mM, and irradiation time of 35 min. The degradation percentage under the Response Surface Methodology (RSM) was utilized as a statistical tool to correlate influential parameters. Four consecutive reusability trials were performed to assess catalyst stability.

Photoinduction of Pt single atoms decorated on UiO-66-NH2 for photocatalytic extraction of uranium under open system

The photocatalytic method has been proven as one of the effective methods for uranium removal from radioactive wastewater. Herein, a photocatalyst UiO-66-NH2-Pt was prepared using the adsorption-photoinduction method. Pt was first adsorbed on the substrate and then photo-reduced under light irradiation to be doped into the structure of UiO-66-NH2. The characterization results implied the formation and atomic dispersion of Pt with a loading content of 1.90 wt%. The loading of Pt has promoted the effective separation and transfer of photogenerated electron-hole pairs, broadened the visible light adsorption range and narrowed down the bandgap, thus to enhance the photocatalytic activity. Then they were applied for the photo-removal of uranium under air atmosphere. The reaction rate of UiO-66-NH2-Pt was about 7 times that of pure UiO-66, confirming the higher photocatalytic activity after the loading of Pt. It showed good reusability and was also universal for different water matrix. The detection of hydroxyl radicals with EPR method indicated the formation of H2O2, which could react with uranyl ions to form metastudtite under air. This work further verified the feasibility of photoinduced synthesis of Pt single atom and provided a novel material for photocatalytic removal of uranyl ion under air.

Surface oxidation of carbon dots enables highly selective and sensitive chemiluminescence detection of hydroxyl radical

Surface oxidation of carbon dots enables highly selective and sensitive chemiluminescence detection of hydroxyl radical

A Novel Cerium Oxide/Gold/Carbon Nanocomposite-Based Electrochemical Sensor for Detecting Hydroxyl Radicals

Hydroxyl radicals (•OH), a type of reactive oxygen species (ROS), play a crucial role in maintaining the normal physiological processes of human cells. Nevertheless, an excessive accumulation of these radicals may perturb cellular mechanisms, so triggering the onset of severe diseases, including cancer, neurological disorders, and heart disease. The detection of •OH is thus of utmost importance in the early diagnosis of these disorders. The combination of an electrochemical methodology with a recognition system is considered as a promising approach for the detection of •OH. This is primarily due to its capacity to provide fast and direct readings without the need for any preliminary sample preparation. This study presents the development of a new electrochemical sensor for the detection of •OH. The sensor was developed by modifying a screen-printed carbon electrode (SPCE) with a nanocomposite consisting of cerium oxide nanoclusters (CeOx), gold nanoparticles (AuNPs), and a highly conductive carbon. The synthesis of AuNPs supported by carbon was carried out using a deposition-precipitation process. Subsequently, the meticulous deposition of CeOx nanoclusters onto the AuNPs was achieved by the use of surface organometallic chemistry (SOMC). Energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) were applied to assess the distribution of AuNPs on the carbon substrate and their subsequent embellishment with CeOx nanoclusters. The actual loadings of Ce and Au present in the nanocomposite were measured using inductively coupled plasma optical emission spectroscopy (ICP-OES). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to analyze the electrochemical responses resulting from the interaction of the CeOx-Au/Carbon nanocomposite with •OH. The CV results demonstrated that the proposed sensor exhibited the capability to effectively identify the presence of •OH in the Fenton reaction, with a notably low limit of detection of 58 µM. The sensor demonstrated a linear correlation between the current response and the concentration of •OH, within the range of 0.05 to 5 mM. Compared to a sensor modified with CeOx/Carbon, the CeOx-Au/Carbon-modified sensor exhibited enhanced electrochemical performance, as demonstrated by an increased current response and a reduced peak potential difference when detecting •OH radicals. Furthermore, the EIS studies showed that the sensor could distinguish •OH from other comparable ROS, such as hydrogen peroxide (H2O2).

Highly Sensitive Surface-Enhanced Raman Scattering Detection of Hydroxyl Radicals in Water Microdroplets Using Phthalhydrazide/Ag Nanoparticles Nanosensor.

The spontaneous generation of hydrogen peroxide (H2O2) within atmospheric microdroplets, such as raindrops and aerosols, plays a crucial role in various environmental processes including pollutant degradation and oxidative stress. However, quantifying hydroxyl radicals (•OH), essential for H2O2 formation, remains challenging due to their short lifespan and low concentration. This study addresses this gap by presenting a highly sensitive and selective surface-enhanced Raman scattering (SERS) nanosensor specifically designed for quantifying •OH within water microdroplets. Utilizing a phthalhydrazide (Phth) probe, the SERS technique enables rapid, interference-free detection of •OH at nanomolar concentrations. It achieves a linear detection range from 2 nM to 2 μM and a limit of detection as low as 0.34 nM. Importantly, the SERS sensor demonstrates robustness and accuracy within water microdroplets, paving the way for comprehensive mechanistic studies of H2O2 generation in the atmosphere. This innovative approach not only offers a powerful tool for environmental research but also holds potential for advancing our understanding of atmospheric H2O2 formation and its impact on air quality and pollutant degradation.

An innovative dual-organelle targeting NIR fluorescence probe for detecting hydroxyl radicals in biosystem and inflammation models

The hydroxyl radical (OH) is highly reactive and plays a significant role in a number of physiological and pathological processes within biosystems. Aberrant changes in the level of hydroxyl radical are associated with many disorders including tumor, inflammatory and cardiovascular diseases. Thus, detecting reactive oxygen species (ROS) in biological systems and imaging them is highly significant. In this work, a novel fluorescent probe (HR-DL) has been developed, targeting two organelles simultaneously. The probe is based on a coumarin-quinoline structure and exhibits high selectivity and sensitivity towards hydroxyl radicals (OH). When reacting with OH, the hydrogen abstraction process released its long-range π-conjugation and ICT processes, leading to a substantial red-shift in wavelength. This probe has the benefits of good water solubility (in its oxidative state), short response time (within 10 s), and unique dual lysosome/mitochondria targeting capabilities. It has been applied for sensing OH in biosystem and inflammation mice models.

A dual-oxidant sensing fluorescence probe for detecting hydroxyl radicals and hypochlorous acid in living cells and zebrafish

Reactive oxygen species (ROS) controls several physiological processes, including phagocytosis and pathogen destruction. Thus, it is necessary to developed reliable and effective tools to detect them. Here, in this work, we synthesized the first fluorescent probe (HR-SN) for dual-oxidant detection with quick, sensitive, and specific identification of •OH and HOCl in an aqueous solution. This probe contains a thiomorpholine group for detecting HOCl and an acetyl group that serves as the recognition site for the detection of hydroxyl radicals. HR-SN exhibits a distinct increase in fluorescence when exposed to •OH and HOCl, with a significant Stokes shift, rapid responses, and high sensitivity. The biological imaging results demonstrate that the probe is suitable for fluorescence imaging of living cells and living zebrafish. We anticipate that the concept and design outlined in this study could be a valuable reference for constructing fluorescence probes to detect reactive ROS for analytical and medical applications.

Role of alumina particles in chemical-mechanical synergies in ruthenium polishing

Abrasive particles are usually considered to only play a "mechanical wear" role in the metal chemical mechanical polishing (CMP) process, neglecting their influence on chemical reactions. This study reveals the chemical role of Al2O3 particles in ruthenium (Ru) CMP by comparing the properties and polishing performance of Al2O3-SiO2 mixed slurry and pure SiO2 slurry. Several testing methods are used to investigate the mechanical and chemical actions of Al2O3 particles, including particle size distribution, Zeta potential, electrochemical reaction kinetics, oxide layer property and hydroxyl radical detection test. The results indicate that Al2O3 particles enhance the mechanical action by reducing the Zeta potential, and promote the chemical action by catalyzing hydrogen peroxide to produce hydroxyl radical (Fenton-like reaction) on Ru surface. These increase the material removal rate of Ru CMP with mixed slurry by nearly 5 times, while the surface roughness decreases by 60 %. The mechanism of chemical reaction promoted by increasing the hydroxyl radical concentration on Ru surface is confirmed from the aspects of increased corrosion current, oxide layer thickness and proportion of higher-valence Ru oxide (RuO2) in the oxide layer. Among them, the thickened oxide layer is a significant factor contributing to the substantial improvement in the material removal rate of Ru and the reduction in surface roughness. This study enhances the understanding of the chemical-mechanical synergistic mechanism of abrasive particles in metal polishing and elucidates the principle of this mechanism on promoting material removal and surface quality. It also provides new research ideas and theoretical guidance for efficient and high-quality metal polishing.

A dual-emission mitochondria targeting fluorescence probe for detecting hydroxyl radical and its generation induced by cellular activities

The hydroxyl radical (•OH), a member of the reactive oxygen species (ROS) family, is mainly reactive and toxic, promotes the harmful effects of oxidative stress, and ultimately leads to programmed cell death and organ malfunction. In order to assess the function that the hydroxyl radical (•OH) plays in physiological and pathological processes, it is crucial to detect and image the radical with high sensitivity and selectivity in biological systems. Here, a novel dual-emission fluorescence probe was designed based on a coumarin-quinoline scaffold that could detect coumarin-quinoline •OH with high selectivity, sensitivity, fast responses, and good biocompatibility. This probe is mito-targeting with two well-resolved (172 nm) emission peaks and can be used to image endogenous •OH in living cells and zebrafish under complex conditions. Besides, by tracking the level of hydroxyl radical in mitochondria and nuclei, we have revealed the two different pathways of •OH generation that occurs in cell apoptosis induced by β-lapachone (β-Lap) and lipopolysaccharide (LPS) for the first time by fluorescence probe.

Recent Advances in Detection of Hydroxyl Radical by Responsive Fluorescence Nanoprobes.

Hydroxyl radical (•OH), a highly reactive oxygen species (ROS), is assumed as one of the most aggressive free radicals. This radical has a detrimental impact on cells as it can react with different biological substrates leading to pathophysiological disorders, including inflammation, mitochondrion dysfunction, and cancer. Quantification of this free radical in-situ plays critical roles in early diagnosis and treatment monitoring of various disorders, like macrophage polarization and tumor cell development. Luminescence analysis using responsive probes has been an emerging and reliable technique for in-situ detection of various cellular ROS, and some recently developed •OH responsive nanoprobes have confirmed the association with cancer development. This paper aims to summarize the recent advances in the characterization of •OH in living organisms using responsive nanoprobes, covering the production, the sources of •OH, and biological function, especially in the development of related diseases followed by the discussion of luminescence nanoprobes for •OH detection.

Dimethyl Sulfoxide: An Ideal Electrochemical Probe for Hydroxyl Radical Detection.

In situ and real-time determination of hydroxyl radicals (•OH) in physiological and pathological processes is a great challenge due to their ultrashort lifetime. Herein, an electrochemical method was developed by using dimethyl sulfoxide (DMSO) as a trapping probe for rapid determination of •OH in aqueous solution. When DMSO reacted with •OH, an intermediate product methane sulfinic acid (MSIA) was formed, which can be electrochemically oxidized to methanesulfonic acid (MSA) on the glassy carbon electrode (GCE), resulting in a distinct voltammetric signal that is directly proportional to the concentration of •OH. Other commonly encountered reactive oxygen species (ROS), including hypochlorite anions (ClO-), superoxide anions (O2•-), sulfate radicals (SO4•-), and singlet oxygen (1O2), have showed no interference for •OH determination. Thus, an electrochemical method was developed for the determination of •OH, which exhibits a wide linear range (0.4-5120 μM) and a low limit detection of 0.13 μM (S/N = 3) and was successfully applied for the quantification of •OH in aqueous extracts of cigarette tar (ACT). Alternatively, the same reaction mechanism is also applicable for the determination of DMSO, in which a linear range of 40-320 μM and a detection limit 13.3 μM (S/N = 3) was achieved. The method was used for the evaluation of DMSO content in cell cryopreservation medium. This work demonstrated that DMSO can serve as an electrochemical probe and has valuable application potential in radical study, biological research, and environmental monitoring.

Ratiometric electrochemical determination of hydroxyl radical based on graphite paper modified with metal-organic frameworks and impregnated with salicylic acid.

Hydroxyl radical (•OH) detection is pivotal in medicine, biochemistry and environmental chemistry. Yet, electrochemical method-specific detection is challenging because of hydroxyl radicals'high reactivity and short half-life. In this study, we aimed to modify the electrode surface with a specific recognition probe for •OH. To achieve this, we conducted a one-step hydrothermal process to fabricate a CoZnMOF bimetallic organic framework directly onto conductive graphite paper (Gp). Subsequently, we introduced salicylic acid (SA) and methylene blue (MB), which easily penetrated the pores of CoZnMOF. By selectively capturing •OH by SA and leveragingtheelectrochemical signal generated by the reaction product, we successfully developed an electrochemical sensor Gp/CoZnMOF/SA + MB. The prepared sensor exhibited a good linear relationship with •OH concentrations ranging from 1.25 to 1200 nM, with a detection limit of 0.2 nM. Additionally, the sensor demonstrated excellent reproducibility and accuracy due to the incorporation of an internal reference. It exhibited remarkable selectivity for •OH detection, unaffected by otherelectrochemically active substances. The establishment of this sensor provides a way to construct MOF-modified sensors for the selective detection of other reactive oxygen species (ROS), offering a valuable experimental basis for ROS-related disease research and environmental safety investigations.

Constructing Z-Scheme 3D WO3@Co2SnO4 Heterojunction as Dual-Photocathode for Production of H2O2 and In-Situ Degradation of Organic Pollutants

As photoelectrochemical catalyst material, Z-scheme heterojunction 3D WO3@Co2SnO4 composites were designed through a hydrothermal-calcination method. The morphology and structure were characterized by SEM, EDS, XRD, XPS, DRS, and Mott–Schottky analysis, and the photoelectrochemical properties were explored with the transient photocurrent and electrochemical impedance. The construction of Z-scheme heterojunction markedly heightened the separation efficiency of photogenerated electron-hole pairs of WO3 and enhanced the light absorption intensity, retaining the strong redox ability of the photocatalyst. The 3D WO3@Co2SnO4 was used as a photocathode for production of H2O2. Under the optimal reaction conditions, the yield of H2O2 can reach 1335 μmol·L−1·h−1. The results of free radial capture and rotating disc test revealed the existence of direct one-step two-electron and indirect two-step one-electron oxygen reduction to produce H2O2. Based on the excellent H2O2 production performance of the Z-scheme heterojunction photoelectrocatalytic material, 3D WO3@Co2SnO4 and stainless-steel mesh were used to construct a dual-cathode photoelectric-Fenton system for in-situ degradation of a variety of pollutants in water, such as dye (Methyl orange, Rhodamine B), Tetracycline, sulfamethazine, and ciprofloxacin. The fluorescence spectrophotometry was used to detect hydroxyl radicals with terephthalic acid as a probe. Also, the photocatalytic degradation mechanism was revealed, indicating the dual-cathode photoelectron-Fenton system displayed satisfactory potential on degradation of different types of environmental pollutants. This work provided insights for designing high-activity photoelectrocatalytic materials to produce H2O2 and provided possibility for construction of a photoelectric-Fenton system without extra additions.

Preparation of molecularly imprinted electrochemical sensors for selective detection of hydroxyl radicals based on reduced graphene oxide nanosilver (rGO/AgNPs) composites

An electrochemical sensor for selective detection of hydroxyl radicals (OH) has been developed, which is based on silver nanoparticles and reduced graphene oxide composites (rGO/AgNPs) synthesized in situ by the green reduction method, combined with the electrochemical polymerization method for preparation of molecularly imprinted polymers (MIPs) to modify the screen-printed electrodes. During the assay, the concentration of hydroxyl radicals was obtained by capturing the product 2,5-dihydroxybenzoic acid (2,5-DHBA). Under the optimal experimental conditions, the oxidation peak currents of the target 2,5-DHBA by differential pulse voltammetry (DPV) and its concentration showed a good linear relationship in the concentration ranges of 0.1 ∼ 0.5 μM and 1 ∼ 100 μM, with the limit of detection (LOD) of 0.021 μM. Interference experiments and other studies were also carried out, and the results showed that the sensor has good reproducibility, stability, and selectivity, and the comparison of the detection results with the conventional detection method, high-performance liquid chromatography, indicated the accuracy of the sensor detection, which is a convenient, sensitive, and efficient method for the detection of hydroxyl radicals.

Green Emissive Molybdenum Nanoclusters for Selective and Sensitive Detection of Hydroxyl Radical in Water Samples.

In this work, Cassia tora (C. tora) have been used as a template to synthesize green fluorescent C. tora molybdenum nanoclusters (C. tora-MoNCs) through a green chemistry approach. These C. tora-MoNCs showed a quantum yield (QY) of 7.72% and exhibited a significant emission peak at 498 nm when excited at 380 nm. The as-prepared C. tora-MoNCs had an average size of 3.48 ± 0.80 nm and showed different surface functionality. The as-synthesized C. tora-MoNCs were successfully identified the hydroxyl radical (•OH) via a fluorescence quenching mechanism. Also, fluorescence lifetime and Stern-Volmer proved that after the addition of •OH radicals it was quenched the fluorescence intensity via a static quenching mechanism. The limit of detection is 9.13 nM, and this approach was successfully utilized for sensing •OH radicals in water samples with a good recovery rate.

Quantifying hydroxyl radicals generated by a low-temperature plasma using coumarin: methodology and precautions.

The detection and quantification of hydroxyl radicals (HO˙) generated by low-temperature plasmas (LTPs) are crucial for understanding their role in diverse applications of plasma radiation. In this study, the formation of HO˙ in the irradiated aqueous phase is investigated at various plasma parameters, by probing them indirectly using the coumarin molecule. We propose a quantification methodology for these radicals, combining spectrophotometry to study the coumarin reaction with hydroxyl radicals and fluorimetry to evaluate the formation yield of the hydroxylated product, 7-hydroxycoumarin. Additionally, we thoroughly examine and discuss the impact of pH on this quantification process. This approach enhances our comprehension of HO˙ formation during LTP irradiation, adding valuable insights to plasma's biological applications.

Responsive Nanoprobe for Ratiometric Florescence Detection of Hydroxyl Radical in Macrophage Polarization

Quantification of hydroxyl radical (•OH), one form of reactive oxygen species (ROS), plays critical roles in early diagnosis and treatment monitoring of various diseases. In this work, we report the...

A dual-functional fluorescence probe for detection of Aβ aggregates and hydroxyl radicals

Synchronous detection of Aβ aggregates and reactive oxygen species (ROS) would provide direct insight to reveal the complicated correlations between the two crucial Alzheimer’s disease (AD) hallmarks. Herein, the first fluorescence probe (Quin-HCy) for dual-functional detection of Aβ aggregates and the highly destructive ROS hydroxyl radicals (•OH) is developed. Quin-HCy is designed with a blood-brain barrier (BBB) permeable quinoline fluorophore and a •OH-responsive hydrocyanine moiety. Quin-HCy shows obvious fluorescence increases in response to Aβ aggregates and •OH at 450 nm and 770 nm, respectively. The large spectral shift (∼ 320 nm) is advantageous for the independent detection of these two analytes in two distant channels. Quin-HCy has been used to image •OH in cells through the addition of Fenton reagents, stimulation with PMA and induction of ferroptosis. Most importantly, fluorescence imaging with Quin-HCy shows that significant •OH is generated in Aβ aggregate-treated neuron cells, which provides direct evidence for the high dependence between Aβ aggregates and •OH in the etiology of AD. Besides, Quin-HCy has favorable BBB permeability, and is able to image Aβ plaques and •OH in AD mice brain slices.