Superior Peroxidase-like Activity Research Articles

Novel Approach for the Decoration of Magnetic Carbon Nanospheres with Platinum Nanoparticles and Their Enhanced Peroxidase Activity for the Colorimetric Detection of H2O2

Pt/Fe3O4-DIB-DETA-CNS(PFDDC) nanocomposite(DIB=2,4-dihydroxybenzaldehyde; DETA=diethylene-triamine; CNS=carbon nanosphere) was synthesized by dispersing Pt nanoparticles on magnetic carbon nanospheres. The structure, morphology and composition of the nanocomposite were studied by X-ray diffraction(XRD), transmission electron microscopy(TEM), energy-dispersive X-ray spectroscopy(EDX) and X-ray photoelectron spectroscopy(XPS). In addition, the nanocomposite showed superior peroxidase-like activity towards 3,3′,5,5′-tetramethylbenzidine(TMB) with a visual color change in the presence of hydrogen peroxide(H2O2). Therefore, the PFDDC nanocomposite provides a sensing platform for the colorimetric detection of H2O2 with high sensitivity and selectivity. Furthermore, the nano-composite can be conveniently preserved and separated. These features enable the nanocomposite to colorimetrically detect H2O2 for potential pharmaceutical, environmental and industrial applications.

Colorimetric determination of Hg2+ in environmental water based on the Hg2+-stimulated peroxidase mimetic activity of MoS2-Au composites

A colorimetric assay is described for sensitive determination of Hg2+ ions based on the MoS2-Au composites as peroxidase mimetics, which are synthesized by microwave-assisted solvothermal method. The addition of Hg2+ stimulates their peroxidase-like activity, along with lower Michaelis constant toward the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with H2O2, allowing the composites for direct determination of Hg2+. A broad linear response is obtained ranging from 20 nM to 20 μM with a detection limit (LOD) of 5 nM. The superior peroxidase-like activity is attributed to the large surface area of MoS2 nanosheets and the synergistic catalytic effect of MoS2 and Au. The Hg2+-stimulation effect implies the strong interaction between Hg2+ and MoS2-Au, where the XPS results confirm the presence of metallic Hg0, indicative of an Au-Hg amalgam. This colorimetric assay is successfully applied for the determination of Hg2+ in environmental water (tap water and Yellow River water) with excellent selectivity over interfering cations.

Fabrication of Tubelike Co3O4 with Superior Peroxidase-Like Activity and Activation of PMS by a Facile Electrospinning Technique

Tubelike Co3O4 was successfully prepared by a facile electrospinning route combined with a subsequent calcining treatment. The as-prepared tubelike Co3O4 was exploited as peroxidase mimics and to a...

A Facile synthesis of superparamagnetic Fe3O4 nanofibers with superior peroxidase-like catalytic activity for sensitive colorimetric detection of l-cysteine

Superaramagnetic Fe3O4 nanomaterials are good candidates as enzyme mimics due to their excellent catalytic activity, high stability and facile synthesis. However, the morphology of Fe3O4 nanomaterials has much influence on their enzyme-like catalytic activity. In this work, we have developed a simple polymer-assisted thermochemical reduction approach to prepare Fe3O4 nanofibers for peroxidase-like catalytic applications. The as-prepared Fe3O4 nanofibers show a higher catalytic activity than commercial Fe3O4 nanoparticles. The steady-state kinetic assay result shows that the Michaelis–Menten constant value of the as-obtained Fe3O4 nanofibers is similar to that of horseradish peroxidase (HRP), indicating their superior affinity to the 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 substrate. Based on the outstanding catalytic activity, a sensing platform for the detection of l-cysteine has been performed and the limit of detection is as low as 0.028 μM. In addition, an excellent selectivity toward l-cysteine over other types of amino acids, glucose and metal ions has been achieved as well. This work offers an original means for the fabrication of superparamagnetic Fe3O4 nanofibers and demonstrates their delightful potential applications in the fields of biosensing, environmental monitoring, and medical diagnostics.

Synthesis of hierarchical Co3O4@NiO core-shell nanotubes with a synergistic catalytic activity for peroxidase mimicking and colorimetric detection of dopamine

Fabrication of core-shell nanostructured catalyst is a promising way for tuning its catalytic performance due to the highly active interface and rich redox properties. In this work, hierarchical Co3O4@NiO core-shell nanotubes are fabricated by the deposition of NiO shells via a chemical bath treatment using electrospun Co-C composite nanofibers as templates, followed by a calcination process in air. The as-prepared Co3O4@NiO core-shell nanotubes exhibit a uniform and novel hollow structure with Co3O4 nanoparticles attached to the inner wall of NiO nanotubes and excellent catalytic activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Due to the synergistic effect, the peroxidase-like activity of the Co3O4@NiO core-shell nanotubes is much higher than that of individual Co3O4 and NiO components. Owing to the superior peroxidase-like activity, a simple and rapid colorimetric approach for the detection of dopamine with a detection limit of 1.21µM and excellent selectivity has been developed. It is anticipated that the prepared Co3O4@NiO core-shell nanotubes are promising materials applied for biomedical analysis and environmental monitoring.

Hierarchical NiCo₂O₄ Hollow Sphere as a Peroxidase Mimetic for Colorimetric Detection of H₂O₂ and Glucose.

In this work, the hierarchical NiCo2O4 hollow sphere synthesized via a “coordinating etching and precipitating” process was demonstrated to exhibit intrinsic peroxidase-like activity. The peroxidase-like activity of NiCo2O4, NiO, and Co3O4 hollow spheres were comparatively studied by the catalytic oxidation reaction of 3,3,5,5-tetramethylbenzidine (TMB) in presence of H2O2, and a superior peroxidase-like activity of NiCo2O4 was confirmed by stronger absorbance at 652 nm. Furthermore, the proposed sensing platform showed commendable response to H2O2 with a linear range from 10 μM to 400 μM, and a detection limit of 0.21 μM. Cooperated with GOx, the developed novel colorimetric and visual glucose-sensing platform exhibited high selectivity, favorable reproducibility, satisfactory applicability, wide linear range (from 0.1 mM to 4.5 mM), and a low detection limit of 5.31 μM. In addition, the concentration-dependent color change would offer a better and handier way for detection of H2O2 and glucose by naked eye.

High-index {hk0} faceted platinum concave nanocubes with enhanced peroxidase-like activity for an ultrasensitive colorimetric immunoassay of the human prostate-specific antigen.

Developing simple, high-efficiency non-enzyme bioassays is of great importance for modern analytical systems, but remains a significant challenge. One promising route is to utilize highly efficient nanocatalysts with the exposure of active crystal facets. Herein, we for the first time propose a novel colorimetric immunoassay for the ultrasensitive detection of the human prostate-specific antigen (PSA) based on using a unique type of nanolabel - high-index {hk0} faceted platinum concave nanocubes (HIF-Pt-CNCs). The proposed HIF-Pt-CNCs exhibit superior peroxidase-like catalytic activity that is ∼1500- and ∼4-fold higher than that of natural horseradish peroxidase and Pt nanospheres, respectively, and thereby can provide powerful signal amplification by catalyzing the oxidation of peroxidase substrates in the presence of hydrogen peroxide. Using the HIF-Pt-CNC-labelled anti-PSA detection antibody as a signal probe, the immunoassay is carried out in anti-PSA capture antibody-immobilized microplate wells in a sandwich-type detection mode. Under optimal conditions, the developed immunoassay is able to achieve high sensitivity and specificity for PSA detection in a linear range of 20-2000 pg mL-1 and with an ultralow detection limit of 0.8 pg mL-1, which is much lower than that of conventional enzyme-linked immunosorbent assay (ELISA). Moreover, the method is validated for the analysis of 10 PSA clinical serum specimens, and the results agree very well with those obtained by using a commercialized ELISA kit. Therefore, this new, facile and efficient immunoassay is a promising technique with potential applications in medical science research and clinical diagnosis.

Boosting the Peroxidase-Like Activity of Nanostructured Nickel by Inducing Its 3+ Oxidation State in LaNiO3 Perovskite and Its Application for Biomedical Assays.

Catalytic nanomaterials with intrinsic enzyme-like activities, called nanozymes, have recently attracted significant research interest due to their unique advantages relative to natural enzymes and conventional artificial enzymes. Among the nanozymes developed, particular interests have been devoted to nanozymes with peroxidase mimicking activities because of their promising applications in biosensing, bioimaging, biomedicine, etc. Till now, lots of functional nanomaterials have been used to mimic peroxidase. However, few studies have focused on the Ni-based nanomaterials for peroxidase mimics. In this work, we obtained the porous LaNiO3 nanocubes with high peroxidase-like activity by inducing its 3+ oxidation state in LaNiO3 perovskite and optimizing the morphology of LaNiO3 perovskite. The peroxidase mimicking activity of the porous LaNiO3 nanocubes with Ni3+ was about 58~fold and 22~fold higher than that of NiO with Ni2+ and Ni nanoparticles with Ni0. More, the porous LaNiO3 nanocubes exhibited about 2-fold higher activity when compared with LaNiO3 nanoparticles. Based on the superior peroxidase-like activity of porous LaNiO3 nanocubes, facile colorimetric assays for H2O2, glucose, and sarcosine detection were developed. Our present work not only demonstrates a useful strategy for modulating nanozymes' activities but also provides promising bioassays for clinical diagnostics.

Facile synthesis of iridium nanoparticles with superior peroxidase-like activity for colorimetric determination of H2O2 and xanthine

A facile and efficient method was developed for the preparation of iridium nanoparticles (Ir NPs) with superior peroxidase-like activity. Under the catalytic action of the Ir NPs, the peroxidase substrate 3,3,5,5-tetramathylbenzidine (TMB) can be oxidized by H2O2 to form a blue-colored production oxTMB. Kinetic analysis indicated that the catalytic behavior was in accordance with the typical Michaelis-Menten kinetics and the catalytic reaction followed the ping-pang mechanism. Electron Spin Resonance (ESR) experiment showed that no hydroxyl radical formed in the reaction process. Peroxide substrates with different electron withdrawing ability (benzoyl peroxide, H2O2 and artemisinin) were used to study the catalytic reactions and results indicated that H2O2 can oxidize TMB with much faster rate than artemisinin and slower rate than benzoyl peroxide. These results suggest an electron transfer mechanism was involved in the system of TMB-H2O2-Ir NPs. By using TMB as the colorimetric substrate, H2O2 can be rapidly determined and the method was extended for the determination of xanthine based on its production of H2O2 in the presence of xanthine oxidase. The prepared Ir NPs exhibit good stability in wide range of pH and temperature. The Ir NPs retained at least 90% of their initial catalytic activity after stored at ambient temperature for three months. The high specificity for H2O2 and the excellent stability of the peroxidase-like Ir NPs showed the great application potential in biotechnology field.

Montmorillonite-loaded ceria nanocomposites with superior peroxidase-like activity for rapid colorimetric detection of H2O2

An efficient novel colorimetric sensor for H2O2 based on peroxidase-like CeO2-montmorillonite (MMT) nanocomposites that were successfully prepared by a facile one-pot approach, was realized. In comparison with other nanomaterials as peroxidase mimics, the catalytic reaction by the well-dispersed CeO2-MMT nanocomposites was in accordance with typical Michaelis–Menten kinetics, which exhibited a higher affinity to 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2, bringing about a superior peroxidase-like activity (a distinct blue color change was observed rapidly within 30s, by the naked eye.) than that of pure CeO2 nanoparticles, MMT and their hybrid materials, respectively. Under the optimized conditions, CeO2-MMT nanocomposites were used to establish a colorimetric biosensor for the detection of H2O2 in a relative wide range of 9×10−6M to 5×10−4M with a lower detection limit of 7.8×10−6M. The sensor was successfully applied in H2O2 detection in milk samples.

Cu0.89Zn0.11O, A New Peroxidase-Mimicking Nanozyme with High Sensitivity for Glucose and Antioxidant Detection.

Nanomaterial-based enzyme mimetics (nanozymes) is an emerging field of research that promises to produce alternatives to natural enzymes for a variety of applications. The search for the most cost-effective and efficient inorganic nanomaterials, such as metal oxides, cannot be won by pristine CuO. However, unlike CuO, the Zn-doped CuO (Zn-CuO) nanoparticles reported in this paper reveal superior peroxidase-like enzyme activity. This places Zn-CuO in a good position to participate in a range of activities aimed at developing diverse enzyme applications. The peroxidase-like activity was tested and confirmed against various chromogenic substrates in the presence of H2O2 and obeyed the Michaelis-Menten enzymatic pathway. The mechanism of enhanced enzymatic activity was proved by employing terephthalic acid as a fluorescence probe and by electron spin resonance. The nanozyme, when tested for the detection of glucose, showed a substantial enhancement in the detection selectivity. The limit of detection (LOD) was also decreased reaching a limit as low as 0.27 ppm. Such a low LOD has not been reported so far for the metal oxides without any surface modifications. Moreover, the nanozyme (Zn-CuO) was utilized to detect the three antioxidants tannic acid, tartaric acid, and ascorbic acid and the relative strength of their antioxidant capacity was compared.

Synthesis of Cu2O nanowire mesocrystals using PTCDA as a modifier and their superior peroxidase-like activity

Cu2O nanowire mesocrystals (NWMCs), which possess well-defined octahedral morphology and high-porosity architecture with anisotropic interpenetrating nanowires, have attracted considerable attention owing to their superior physical and chemical properties. However, the current synthetic approach for Cu2O NWMCs using graphene oxide as modifier leads to uncontrollable products and low productivity (~30 %), which largely hinder their further industrial application. Herein, we report a modified synthetic approach for controllable and large-scale preparation of Cu2O NWMCs using perylene-3,4,9,10-tetracarboxylic dianhydride molecule as modifier. The effects of growth time and initial pH on the morphology of final products have been systemically investigated. Under the optimal reaction condition with initial pH of 5.3 and reaction time of 15 h, the well-defined octahedral Cu2O NWMCs can be obtained with a productivity as high as ~75 %. In addition, this synthetic approach can be easily scaled up from 50 to 500 mL autoclave. The ability of high productivity and reproducibility in synthesis of Cu2O NWMCs enable us to further study their peroxidase-like activity by catalyzing the oxidation of o-phenylenediamine in the presence of H2O2. The Cu2O NWMCs have exhibited a superior catalytic activity with the K cat of 1.14 × 10−2, 10 times higher than that of horseradish peroxidase. Moreover, the Cu2O NWMCs can also retain 69.5 % of their initial activities after 10-batch redox reactions. Our results provide a facile approach to controllable and large-scale synthesis of Cu2O NWMCs using homogeneous molecule modifier and open up opportunities to use Cu2O NWMCs as nanozyme for future industrial application.

Platinum nanoparticles on reduced graphene oxide as peroxidase mimetics for the colorimetric detection of specific DNA sequence.

In this work, we developed a simple and sensitive colorimetric detection platform for specific DNA sequences by using peroxidase mimetics of platinum nanoparticles supported on reduced graphene oxide. This nanocomposite possessed the combined advantages of platinum nanoparticles (superior peroxidase-like activity) and reduced graphene oxide (π-stacking interaction with single-stranded but not double-stranded DNA). The catalytic activity was strongly dependent on the chloroplatinic acid-to-graphene oxide mass ratio during the synthesis step, with an optimum ratio of 7 : 1. Unlike natural peroxidase, the nanocomposite had excellent stability over wide ranges of temperature (4-90 °C) and pH (1-13). For DNA detection, the nanocomposite had higher affinity for the single-stranded probe (in the absence of target) than the probe-target duplex. The probe-bound nanocomposite was stabilized against salt-induced aggregation and thus upon the addition of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide to the supernatant, an intense blue color was generated. The linear range and limit of detection of this assay platform were 0.5-10 nM and 0.4 nM, respectively. Moreover, this platform featured high specificity that 3-base-mismatched sequence could be distinguished with the naked eye and 1-base-mismatched sequence with absorbance measurement. Furthermore, the applicability for real sample detection was demonstrated by polymerase chain reaction product analysis. Taken together, this new platform is well suited for point-of-care and on-site nucleic acid testing.

Aggregation-induced superior peroxidase-like activity of Cu2−xSe nanoparticles for melamine detection

In this work, Cu2−xSe@PSS NPs conjugated with melamine to form Cu2−xSe@PSS NP–melamine aggregates, which improved the peroxidase-like activity of Cu2−xSe@PSS NPs and catalyzed 3,3′,5,5′-tetramethylbenzidine (TMB) to the oxidized TMB in the presence of H2O2. The sensing platform can quantify detection of melamine from 4.7 nM to 29.7 μM. And the detection limit for melamine was as low as 1.2 nM.

Strong coupled palladium nanoparticles decorated on magnetic graphene nanosheets as enhanced peroxidase mimetics for colorimetric detection of H2O2

Herein Pd/Fe3O4-PEI-RGO nanohybrid was synthesized by dispersion of Pd NPs and Fe3O4 NPs on PEI modified graphene oxide sheets. This nanohybrid was found to possess superior peroxidase-like activity, and could efficiently oxidize 3,3′,5,5′-Tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to produce a color reaction. Therefore, this provides a sensing platform for the colorimetric detection of H2O2 in solution. The linear range for H2O2 was from 0.5 to 150 μM and the limit of detection was as low as 0.1 μM. Moreover, the nanohybrids have the advantages of facile preservation and rapid separation. More importantly, comparing with the other catalysts (PEI-RGO, Fe3O4-PEI-RGO and Pd-PEI-RGO), this nanohybrid exhibits the enhanced peroxidase catalytic activity. Thus, it is expected that this nanohybrid could conveniently and efficiently detect H2O2 in the pharmaceutical, environmental and industrial fields.

Highly dispersed CeO₂ on TiO₂ nanotube: a synergistic nanocomposite with superior peroxidase-like activity.

In this report, a novel nanocomposite of highly dispersed CeO2 on a TiO2 nanotube was designed and proposed as a peroxidase-like mimic. The best peroxidase-like activity was obtained for the CeO2/nanotube-TiO2 when the molar ratio of Ce/Ti was 0.1, which was much higher than that for CeO2/nanowire-TiO2, CeO2/nanorod-TiO2, or CeO2/nanoparticle-TiO2 with a similar molar ratio of Ce/Ti. Moreover, in comparison with other nanomaterial based peroxidase mimics, CeO2/nanotube-TiO2 nanocomposites exhibited higher affinity to H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB). Kinetic analysis indicated that the catalytic behavior was in accordance with typical Michaelis-Menten kinetics. Ce(3+) sites were confirmed as the catalytic active sites for the catalytic reaction. The first interaction of surface CeO2 with H2O2 chemically changed the surface state of CeO2 by transforming Ce(3+) sites into surface peroxide species causing adsorbed TMB oxidation. Compared with CeO2/nanowire-TiO2, CeO2/nanorod-TiO2, and CeO2/nanoparticle-TiO2, the combination of TiO2 nanotube with CeO2 presented the highest concentration of Ce(3+) thus leading to the best peroxidase-like activity. On the basis of the high activity of CeO2/nanotube-TiO2, the reaction provides a simple method for colorimetric detection of H2O2 and glucose with the detection limits of 3.2 and 6.1 μM, respectively.

Manganese(iii)meso-tetrakis(4-N-methylpyridyl)-porphyrin and mediator thionine co-decorated DNA nanowires for sensitive electrochemical monitoring of mercury(ii)

We developed a novel electrochemical DNA biosensor for mercury(II) ion (Hg2+) detection on the basis of manganese(III) meso-tetrakis(4-N-methylpyridyl)-porphyrin (MnTMPyP) and electron mediator thionine (Thi) co-decorated DNA nanowires for signal amplification. The T-rich capture DNA assembled on the electrode could successfully immobilize the primer DNA via specific base-pairing, which triggered the hybridization chain reaction (HCR) to form long DNA nanowires with the aim of loading abundant MnTMPyP and electron mediator Thi. In the electrolyte containing H2O2, the MnTMPyP loaded in the DNA nanowires showed superior peroxidase-like activity and electrocatalyzed the reduction of H2O2, promoting the redox reaction of Thi with a dramatically amplified electrochemical signal. However, in the presence of target Hg2+, Hg2+-mediated thymine base pairs (T–Hg2+–T) are formed between the two neighboring T-rich capture DNAs, which resulted in the release of the MnTMPyP and Thi co-decorated DNA nanowires from the electrode surface, providing a reduced readout signal for the quantitative electrochemical detection of Hg2+. The results showed that the proposed electrochemical DNA biosensor was highly sensitive to Hg2+ in the concentration of 1.0 ng L−1 to 107 ng L−1 with a detection limit of 0.5 ng L−1 (2.5 pM), and it also exhibited excellent selectivity against other interferential metal ions.

Protein-directed in situ synthesis of platinum nanoparticles with superior peroxidase-like activity, and their use for photometric determination of hydrogen peroxide

Platinum nanoparticles (Pt-NPs) with sizes in the range from 10 to 30 nm were synthesized using protein-directed one-pot reduction. The model globular protein bovine serum albumin (BSA) was exploited as the template, and the resulting BSA/Pt-NPs were studied by transmission electron microscopy, energy dispersive X-ray spectroscopy, and resonance Rayleigh scattering spectroscopy. The modified nanoparticles display a peroxidase-like activity that was exploited in a rapid method for the colorimetric determination of hydrogen peroxide which can be detected in the 50 μM to 3 mM concentration range. The limit of detection is 7.9 μM, and the lowest concentration that can be visually detected is 200 μM.