Selective Detection Of H2O2 Research Articles

Electrochemistry at Bimetallic Pd/Au Thin Film Surfaces for Selective Detection of Reactive Oxygen Species and Reactive Nitrogen Species.

In this work, we designed and fabricated Pd/Au bimetallic thin film electrodes with isolated Pd nanoparticles via underpotential deposition of copper on a gold substrate followed by in situ redox replace reaction in a Pd salt solution. The Pd/Au electrode was characterized by AFM and XPS as well as multiple electrochemical techniques including CV and electrochemical quartz crystal microbalance (EQCM) in sulfuric acid and phosphate buffer electrolytes. Results show that the reduction reactions of the analytes (i.e., H2O2 and 3-nitrotyrosine (3-NT)) at the Pd/Au thin film surfaces affect the nature and reactivity of Pd/Au surface electrochemistry including the adsorbed/absorbed hydrogen and/or the premonolayer palladium oxide redox processes at Pd. The EQCM experiment supports the arrangement of small size Pd nanoparticles in the Pd thin film in the presence of gold exhibits unusual properties, acting as a new physicochemical dimension between the electrode and target H2O2 and 3-NT molecules. The Pd/Au thin film was demonstrated as an extremely sensitive and selective probe for detection of common ROS and RNS (i.e., H2O2 and 3-NT). The integration of two different metallic species, Pd and Au, into a surface structure on nanoscale by exploiting their unique surface electrochemistry establishes an innovative analytical method for highly sensitive and selective detection of H2O2 and 3-NT simultaneously. This method has a general scope for detecting a broad range of redox active and nonredox active species simultaneously, which opens up new opportunities to develop new electrocatalytic materials and innovative sensing approaches.

Intriguing peroxidase-mimic for H2O2 and glucose sensing: A synergistic Ce2(MoO4)3/rGO nanocomposites

Nanomaterials-based peroxidase mimicking with attractive catalytic activity is an appropriate approach to receive the challenges for replacing natural enzymes. Here, we have been reported rGO/CM based peroxidase mimicking nanocatalyst for sensitive and selective detection of H2O2 and glucose. Time-dependent hydrothermal synthesis of CM nanoparticles with different morphologies and their composites have been designed for glucose sensing application. rGO/CM (6 h) (2:1) catalyst was found to be an excellent intrinsic peroxidase-mimicking nanozyme to oxidize 3, 3′,5, 5′-tetramethylbenzidine (TMB) in the presence of H2O2. This nanozyme holds better affinity towards TMB than natural enzyme-like horseradish peroxidase (HRP) and other nanozymes. Peroxidase–mimicking activity and enzyme kinetics of rGO/CM (6 h) (2:1) catalyst follows the Michaelis – Menten model. This novel metal-free highly sensitive colorimetric biosensor detects H2O2 and glucose precisely. Limit of detection (LOD) and linearity range for H2O2 were found to be 0.15 μM and 1–10 μM whereas for glucose it was 0.43 μM and 1–50 μM respectively. The sensitive and selective detection makes this catalyst as an effective biosensor for various potential applications such as clinical diagnosis, pharmaceutics, and food industry.

Zn- and Cd-based coordination polymers with a novel anthracene dicarboxylate ligand for highly selective detection of hydrogen peroxide.

A one-dimensional {[Zn(L)(DMF)2]}n (1) and a three-dimensional {[Cd(L)(DMF)]·DMF}n (2) coordination polymer based on the novel anthracene derivative H2L (H2L = 4,4'-(9,10-anthracenediyl)dicinnamic acid) were obtained by solvothermal synthesis and charaterised by single-crystal and powder X-ray diffraction, thermogravimetry, and infrared spectroscopy. The anthracene derivative H2L and coordination polymers 1 and 2 were used to modify a glassy carbon electrode and as such served as an active material for detection of H2O2. Cyclic voltammograms in the potential range from 0 to -0.5 V revealed concentration-dependent cathodic current in all three cases with a lower detection limit of 200 μM. The electrode modified with compound 2 showed the best performance towards hydrogen peroxide detection. The results suggest that the development of electrodes modified with inorganic polymers based on highly conjugated ligands can serve as potential electrocatalytic materials.

Effect of sulfur doping on graphene oxide towards amplified fluorescence quenching based ultrasensitive detection of hydrogen peroxide

Fluorescence quenching of fluorescent dyes by metals, metal oxides or carbon nanomaterials is a trending technique for elemental inspection of nanoscale physical and biochemical processes. Development of graphene oxide-based fluorescence sensors has become a hot spot of research for biomedical applications owing to its profound optical, electrical and sensing properties. Chemical doping of graphene oxide leads to upgradation of its intrinsic features. Hence, it is of great interest to investigate doped counterparts of graphene oxide for credible optical and biosensing. In view of this, we herein report successful sulfur doping of graphene oxide with superb catalytic activity towards enhanced fluorescence quenching and ultrasensitive detection of hydrogen peroxide. Results evidence that sulfur doping via hydrothermal treatment greatly influences the surface chemistry, functionalities and thus the catalytic performance of graphene oxide. The high quenching efficiency of sulfur doped graphene oxide can be attributed to its capabilities of good adsorbability and high electron mobility that substantially catalyzes the decomposition of hydrogen peroxide into −OH radicals, consequently quenching the fluorescence of Rhodamine-B efficiently. Characterization tools such as XRD, SEM, FTIR, UV–Vis, XPS, RAMAN spectroscopy were used to investigate the surface chemistry and morphology and chemical composition of the prepared samples. Different parameters such as concentration of dye, amount of dopant, concentration of particles etc.; were explored for ultrasensitive detection of hydrogen peroxide. Under optimal conditions, the limit of detection (LOD) for hydrogen peroxide was as low as 100 pM with linear detection range from 1 nM to 1 µM. Hence, based on our findings, we propose a highly desirable sensitive and selective H2O2 detection method by virtue of high binding affinity and quenching ability of SGO.

TMB-assembly as nanosubstrate construction colorimetric kit for highly sensitive and selective detection of H2O2 and monoamine oxidase-A based on Fenton reaction

Detection of H2O2 is significant for the applications in environmental protection, pharmaceutical industries, food production, and clinical control. Current colorimetric kit of H2O2 based on enzyme or nanomaterials always needs TMB or other peroxidases substrate as coloration species. Herein, we report a simple hydrothermal method to synthesize of TMB dot as the nanosubstrate construction colorimetric kit for highly selective and sensitive detection of H2O2 based on Fenton reaction. Compared with TMB as the substrate, the synthesized TMB dots (TMBDs) show higher reaction activity in the presence of the same low-level Fe2+ and H2O2, resulting in highly sensitive sensing H2O2 down to 0.8 nM. Additionally, the obtained TMBDs can well disperse in solution, while generally TMB as substrate needs to be dissolved in organic solvents such as DMF and DMSO. Furthermore, the developed colorimetric kit is applied in detection of Mao-A, due to the reaction between epinephrine and Mao-A producing H2O2. More importantly, the proposed method has been successfully applied to the analysis of Mao-A in spiked human serum Hence, the TMBDs as the nanosubstrate provide an efficient, fast and sensitive approach for colorimetric kit of H2O2 and Mao-A, promoting more extensive application in early diagnosis of disease and drug discovery.

Metal-doped carbon nanoparticles with intrinsic peroxidase-like activity for colorimetric detection of H2O2 and glucose.

Nanomaterial-based enzyme mimics (nanozymes) are attracting increasing attention because of their low production cost, high stability against denaturation, and resistance to high concentrations of substrates. Here, carbon nanoparticles doped with a small amount (<5 mol%) of Pt (denoted as PtCNPs) are synthesized via a facile, cost-effective hydrothermal treatment of p-phenylenediamine (PPD) and K2PtCl4. The obtained PtCNPs possess high aqueous stability, excellent water-dispersibility, and suitable size (∼15 nm). More interestingly, the PtCNPs exhibit an intrinsic peroxidase-like activity that can quickly catalyze 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) and produce a blue color. Importantly, since satisfactory catalytic properties were also observed when K2PtCl4 was replaced with CuCl2, NiCl2, or Na2PdCl4 during the synthesis, the PPD- and inorganic metal salt-involved hydrothermal synthetic approach may be developed as a general and simple way to fabricate new nanozymes. Besides, the steady-state kinetics reveals that the PtCNPs have a stronger affinity for TMB and a weaker affinity for H2O2 compared with horseradish peroxidase. On the basis of the color reaction, a colorimetric detection method for H2O2 and glucose has been successfully established with a detection limit of 0.15 and 0.30 μM, respectively. Further, the method has also been successfully applied for glucose detection in human serum samples. To sum up, this work develops a new synthetic method of metal-doped carbon nanomaterials and demonstrates their capability for the sensitive and selective detection of H2O2 and glucose, which may foster the development of new nanozymes for biosensing applications.

Gold nanoparticle etching induced by an enzymatic-like reaction for the colorimetric detection of hydrogen peroxide and glucose

A rapid colorimetric method for the sensitive and selective detection of H2O2 and glucose was developed based on the etching of AuNPs.

FeSx-graphene heterostructures: Nanofabrication-compatible catalysts for ultra-sensitive electrochemical detection of hydrogen peroxide

Hydrogen peroxide (H2O2) is one of the most important redox-active metabolites in biological processes, from cell signaling to oxidative stress. Incorporation of catalytic nano-phase heterostructures can significantly improve the detection limit of H2O2 electrochemical sensors. Here, we report an iron sulfide (FeSx)/graphene heterostructure for detection of H2O2 down to ∼500 picoMolar pM, with a dynamic range over six orders of magnitude. By relying on the Fenton reaction, the developed catalyst enables selective detection of H2O2 vs. common redox-active metabolites in physiological condition. Electrochemical analysis reveals a strong substrate-dependent performance, where the type and doping of the graphene layer dramatically impact sensitivity. Specifically, for the first time, the electrochemical performance of chemical vapor deposited versus epitaxial graphene (EG) layers is examined and compared in a systematic way. The results demonstrate that a heterostructure of FeSx with chemical vapor deposited graphene (CVD-G) exhibits the highest reduction in charge transfer resistance (more than 16×), leading to a significantly higher sensitivity compared to n-doped and p-doped EG. Furthermore, the excellent sensitivity and material stability of the developed heterostructures enable in situ detection of redox changes due to heat shock-induced oxidative stress on E. coli cells. Since the developed heterostructures are directly-grown, they can be patterned with nanometer-scale resolution. Hence, this work can open up new possibilities for developing ultracompact devices for monitoring redox changes in situ, with high spatial resolution.

A NIR fluorescent sensor with large Stokes shift for the real-time visualization of endogenous hydrogen peroxide in living cells

Hydrogen peroxide (H2O2), regarded as the byproduct of aerobic metabolism via the electron transport chain, plays a significant role in a vast array of physiological and pathological process in the organisms. Therefore, it is of great importance to develop efficient analytical approach for monitoring the H2O2 level in living systems. Herein, in this work, a NIR fluorescent probe named NDCM-HP was developed for the highly selective detection of H2O2 by introducing boronate group as the recognition unit into the 2-(3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene) malononitrile (NDCM-OH) fluorophore which is featured by strong NIR emission, large Stokes shift, and good photostability. As a matter of fact, NDCM-HP demonstrated excellent sensing performance toward H2O2 in solution samples such as high sensitivity with about 127-fold emission enhancement, low detection limit of 70.189 nM, and good selectivity over biologically related species. Furthermore, it could be employed for detecting endogenous H2O2 fluctuation in living cells induced by different stimulators such as Phorbol myristate acetate (PMA), N-Acetylcysteine (NAC), indicating its great potential in biological application.

A simple boronic acid-based fluorescent probe for selective detection of hydrogen peroxide in solutions and living cells

An approach of high sensitivity and selectivity for hydrogen peroxide (H2O2) detection is highly demanded due to its important roles in regulating diverse biological process. In this work, we introduced an easily synthesized fluorescent “turn off” probe, BNBD. It is designed based on the core structure of 4-chloro-7-nitrobenzofurazan as a fluorophore and incorporated with a specific H2O2-reactive group, aryl boronate, for sensitive and selective detection of H2O2. We demonstrated its selectivity by incubating the probe with other types of ROS, and measured the limit of detection of BNBD as 1.8 nM. BNBD is also conducive to H2O2 detection at physiological conditions. We thus applied it to detect both exogenous and endogenous changes of H2O2 in living cells by confocal microscopy, supporting its future applications to selectively monitor H2O2 levels and identify H2O2-related physiological or pathological responses from live cells or tissues in the near future.

Simultaneously activating highly selective ratiometric MRI and synergistic therapy in response to intratumoral oxidability and acidity

Low selectivity is a major problem for cancer theranostics that has promoted the development of molecularly-responsive nanomaterials. Herein, we report a novel doxorubicin (DOX)-loaded degradable cobalt oxide nanoprism (Co3O4-DOX) for T1/T2 ratiometric magnetic resonance imaging (MRI)-monitored synergistic cancer therapy that simultaneously responds to intratumoral oxidability and acidity. Co3O4-DOX degraded under both H2O2-rich and acidic conditions, producing Co3+ and releasing DOX, not only resulted in an MRI contrast switch from T2 to T1, but also led to DOX luminescence recovery by weakening energy transfer. Thus, highly sensitive and selective H2O2 detection was achieved by these changes in MRI and luminescence signals. Importantly, Co3O4-DOX showed outstanding T1/T2 ratiometric MRI performance in vivo, significantly improving the contrast between tumor and normal tissues. Moreover, the produced Co3+ also resulted in intracellular radical generation for chemodynamic therapy, which had a synergistic effect with the photothermal and chemotherapy induced by Co3O4 and DOX, respectively. Under ratiometric MRI guidance, successful synergistic cancer therapy was performed on a tumor-bearing mice model. This work provides a new imaging application to improve selectivity that uses molecularly-responsive magnetic nanomaterials for ratiometric MRI tumor imaging and cancer theranostics.

Facile preparation of surfactant-free Au NPs/RGO/Ni foam for degradation of 4-nitrophenol and detection of hydrogen peroxide

The application of Au nanoparticles (Au NPs) often requires surface modification with chemical surfactants, which dramatically reduce the surface activity and increase the chemical contamination and cost of Au NPs. In this research, we have developed a novel Au NPs/reduced graphene oxide/Ni foam hybrid (Au NPs/RGO/NiF) by in situ reduction through ascorbic acid and replacement reaction. This method is green, facile and efficient. The Au NPs are free of chemical surfactants and are homogeneously distributed on the surface of the RGO/NiF. The as-prepared Au NPs/RGO/NiF hybrid is uniform, stable and exhibits not only a high reduction efficiency for the reduction of 4-nitrophenol with a catalytic kinetic constant of up to 0.46 min−1 (0.15 cm3 catalysis) but also a sensitive and selective detection of H2O2 with a detection limit of ∼1.60 μM.

Near-infrared and lysosome-targetable fluorescent probe based on phenoxazinium for hydrogen peroxide detection

A phenoxazinium-based near-infrared fluorescent probe was designed and synthesized for rapid and selective detection of H2O2 in lysosomes.

Quantitative analysis of hydrogen peroxide with special emphasis on biosensors.

Determination of hydrogen peroxide (H2O2) has become essential in pharmaceutical, biological, clinical and environmental studies. The conventional detection methods of H2O2 such as colourimetry, titration, chromatography, spectrophotometry, fluorimetry, chemiluminescence have limited success, due to their poor selectivity and sensitivity, long analysis time and lack of long-term reliability and reproducibility. The biosensors overcome these limitations because of their simplicity, rapidity, selectivity and high sensitivity. This review describes the principle, analytic parameters, merits and demerits of various methods of H2O2 determination with special emphasis on biosensors. The classification of biosensors based on various materials/nanomaterials and electrodes have been described in detail. The recent advances in vivo sensing and bio-sensing of H2O2 by hemoglobin nanoparticles are also presented. The significant challenges and future perspective for highly selective H2O2 detection are discussed.

Selective and Mechanically Robust Sensors for Electrochemical Measurements of Real-Time Hydrogen Peroxide Dynamics in Vivo.

Hydrogen peroxide (H2O2) is an endogenous molecule that plays several important roles in brain function: it is generated in cellular respiration, serves as a modulator of dopaminergic signaling, and its presence can indicate the upstream production of more aggressive reactive oxygen species (ROS). H2O2 has been implicated in several neurodegenerative diseases, including Parkinson's disease (PD), creating a critical need to identify mechanisms by which H2O2 modulates cellular processes in general and how it affects the dopaminergic nigrostriatal pathway, in particular. Furthermore, there is broad interest in selective electrochemical quantification of H2O2, because it is often enzymatically generated at biosensors as a reporter for the presence of nonelectroactive target molecules. H2O2 fluctuations can be monitored in real time using fast-scan cyclic voltammetry (FSCV) coupled with carbon-fiber microelectrodes. However, selective identification is a critical issue when working in the presence of other molecules that generate similar voltammograms, such as adenosine and histamine. We have addressed this problem by fabricating a robust, H2O2-selective electrode. 1,3-Phenylenediamine (mPD) was electrodeposited on a carbon-fiber microelectrode to create a size-exclusion membrane, rendering the electrode sensitive to H2O2 fluctuations and pH shifts but not to other commonly studied neurochemicals. The electrodes are described and characterized herein. The data demonstrate that this technology can be used to ensure the selective detection of H2O2, enabling confident characterization of the role this molecule plays in normal physiological function as well as in the progression of PD and other neuropathies involving oxidative stress.

Dual Mechanism of an Intramolecular Charge Transfer (ICT)-FRET-Based Fluorescent Probe for the Selective Detection of Hydrogen Peroxide.

A dual-mechanism intramolecular charge transfer (ICT)-FRET fluorescent probe for the selective detection of H2 O2 in living cells has been designed and synthesized. This probe used a coumarin-naphthalimide hybrid as the FRET platform and a boronate moiety as the recognition group. Upon the addition of H2 O2 , the probe exhibited a redshifted (73 nm) fluorescence emission, and the ratio of fluorescence intensities at λ=558 and 485 nm (F558 /F485 ) shifted notably (up to 100-fold). Moreover, there was a good linearity (R2 =0.9911) between the ratio and concentration of H2 O2 in the range of 0 to 60 μm, with a limit of detection of 0.28 μm (signal to noise ratio (S/N)=3). This probe could also detect enzymatically generated H2 O2 . Importantly, it could be used to visualize endogenous H2 O2 produced by stimulation from epidermal growth factor.

Flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen doped carbon nanotube arrays: In situ electrochemical detection in live cancer cells

The rapidly growing demand for in situ real-time monitoring of chemical information in vitro and in vivo has attracted tremendous research efforts into the design and construction of high-performance biosensor devices. Herein, we develop a new type of flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen-doped carbon nanotube arrays, and explore its practical application in in situ electrochemical detection of cancer biomarker H2O2 secreted from live cancer cells. Our results demonstrate that carbon fiber material with microscale size and fascinating mechanical properties can be used as a robust and flexible microelectrode substrate in the electrochemical biosensor system. And the highly ordered nitrogen-doped carbon nanotube arrays that grown on carbon fiber possess high surface area-to-volume ratio and abundant active sites, which facilitate the loading of high-density and uniformly dispersed gold nanoparticles on it. Benefited from the unique microstructure and excellent electrocatalytic properties of different components in the nanohybrid fiber microelectrode, an effective electrochemical sensing platform based on it has been built up for the sensitive and selective detection of H2O2, the detection limit is calculated to be 50nM when the signal-to-noise ratio is 3:1, and the linear dynamic range is up to 4.3mM, with a high sensitivity of 142µAcm−2mM−1. These good sensing performances, coupled with its intrinsic mechanical flexibility and biocompatibility, allow for its use in in situ real-time tracking H2O2 secreted from breast cancer cell lines MCF-7 and MBA-MD-231, and evaluating the sensitivity of different cancer cells to chemotherapy or radiotherapy treatments, which hold great promise for clinic application in cancer diagnose and management.

Real‐time Selective Detection of Hydrogen Peroxide Based on a Tantalum Deposited Pencil Lead Electrode for Evaluation of Enzyme Activities

AbstractIn this study, we have carried out electrodeposition of tantalum (Ta) nanostructures on pencil lead electrode in non‐aqueous media at room temperature by applying a constant potential. The deposited Ta on pencil lead was examined for the catalytic effect regarding hydrogen peroxide (H2O2) reduction with voltammetry and amperometry. Ta/pencil lead electrode exhibited amperometric sensitivity of 0.317 μA mM−1 cm−2 and fast response time of 0.75 s, where selective detection of H2O2 was fulfilled without interruption from common electroactive biomaterials such as O2, uric acid, ascorbic acid, dopamine, acetamidophenol, and glucose. For practical applications, the dynamic concentration changes of H2O2 during catalase and glucose oxidase‐involved reactions, either eliminating or producing H2O2, were successfully traced in real time with as‐prepared electrode. From the kinetics study for catalase and glucose oxidase, we evaluated Michaelis constants (Kmapp) as 7.8 mM for catalase and 37 mM for glucose oxidase, respectively.

Rational designed benzochalcone-based fluorescent probe for molecular imaging of hydrogen peroxide in live cells and tissues

Hydrogen peroxide (H2O2), a member of reactive oxygen species (ROS), usually acts as a significant oxidative stress marker in some diseases for its abnormal expression. Due to the merits of non-invasive and high selectivity, fluorescent probe has been proved to be an efficient method for H2O2 detection. Herein, we presented two novel boronate probes FD-1 and FD-2, in which the C-B bonds are well suitable for high selective detection of H2O2. Notably, these two probes were based on 4-hydroxybenzochalcone fluorophore, which exhibits excellent fluorescent properties through the intramolecular hydrogen bond. The results demonstrated that these two probes displayed satisfactory sensitivity and selectivity to H2O2, and probe FD-2 displayed faster response rate to H2O2 than FD-1. Importantly, FD-2 was successfully applied to image H2O2 in living cells and tissues, indicating probe FD-2 has great potential to monitor the H2O2 in biological system.

Facile Preparation of High-Performance Copper Oxide Sensors for Electroanalysis of Hydrogen Peroxide

We report on the template electrodeposition of different copper/copper oxide nanoparticles on pencil graphite lead substrate using ionic and neutral surfactant templates. Physical structure and electrochemical properties of the modified electrodes were shown to be influenced by the nature of surfactant template. These copper modified pencil graphite electrodes exhibited very good catalytic activity towards hydrogen peroxide reduction reaction, which could be used for the sensitive and selective detection of H2O2. A maximum sensitivity of ca. 158 µA/mM/cm2, lower limit of detection (LOD) of 0.35 ± 0.04 µM, response time of <2 seconds and a linearity in wide range of concentration from 1 µM to 13 mM were observed. These electrodes were highly selective towards hydrogen peroxide with little interference from glucose, fructose, ascorbic acid, dopamine, uric acid, urea, chlorides, nitrates and sulphates even at 100 fold higher concentrations of the interfering species compared to H2O2 concentration. Practical feasibility of the sensor was demonstrated by detecting H2O2 in human blood serum and milk samples with good recovery. Our methodology enables one to prepare the electrode within two minutes and to complete the analysis within another 60 seconds, enabling the quantitative detection of hydrogen peroxide in less than five minutes using a freshly prepared, cost-effective electrode without any complicated procedure.