Science Bulletin

, Volume 61, Issue 22, pp 1739–1745 | Cite as

Peroxidase-like properties of Ruthenium nanoframes

  • Haihang Ye
  • Jacob Mohar
  • Qingxiao Wang
  • Massimo Catalano
  • Moon J. Kim
  • Xiaohu Xia
Article Materials Science
  • 198 Downloads

Abstract

This work reports the inherent peroxidase-like properties of Ruthenium (Ru) nanoframes. After templating with Palladium (Pd) seeds, Ru nanoframes with an octahedral shape, average edge length of 6.2 nm, and thickness of 1.8 nm were synthesized in high purity (>95 %) and good uniformity. Using the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 as a model catalytic reaction, the Ru frames were demonstrated to be approximately three times more active than natural peroxidases in catalyzing the formation of colored products. As compared to their natural counterparts, Ru frames have a stronger binding affinity to TMB as well as a weaker binding affinity to hydrogen peroxide during the catalysis. The Ru frames as peroxidase mimics proved to be chemically and thermally stable. This work represents the first demonstration of Ru nanostructure-based peroxidase mimics and is therefore expected to inspire future research on bio-applications of Ru nanomaterials.

Keywords

Ruthenium Nanoframes Peroxidase Enzyme mimic Catalysis 

摘要

本研究报道了钌纳米框架的过氧化物酶属性。选用钯纳米晶种为模板,可以制备得到具有八面体形貌的钌纳米框架,其平均边长为6.2纳米,厚度为1.8纳米,产物产率高(>95 %)并且形貌均匀。以过氧化氢氧化3,3′,5,5′-四甲基联苯胺分子(TMB)反应为催化模型,钌纳米框架的过氧化物酶活性比天然过氧化物酶高出接近3倍。和天然过氧化物酶相比,钌纳米框架在催化反应的过程中对3,3′,5,5′-四甲基联苯胺的结合力较强,但是对过氧化氢的结合力较弱。同时,钌纳米框架在催化反应中展示出较好的化学和热力学稳定性能。本研究首次提出了一种基于钌纳米晶的过氧化物模拟酶, 为钌纳米结构在生物应用方向的发展提供新的思路和前景。

1 Introduction

Peroxidase mimics of inorganic nanomaterials hold great potential for replacing natural peroxidases in diagnostic, sensing, and imaging applications, providing enhanced performance [1, 2, 3, 4, 5, 6, 7, 8]. Since the first demonstration of ferromagnetic nanoparticles as peroxidase mimics [9], a vast variety of inorganic nanomaterials have been reported to show peroxidase-like properties, including nanostructures made of metal oxides [10, 11, 12, 13, 14], noble metals [15, 16, 17, 18, 19, 20, 21], carbon materials [22, 23, 24], and a combination of them [25, 26]. Among them, noble-metal mimics are particularly intriguing because: (1) they are ultra-stable owing to their chemical inertness, enabling them to survive harsh environments; and (2) their surfaces can be conveniently functionalized with biomolecules by means of metal-thiolate bonding [27], facilitating biomedical applications. While peroxidase-like properties have been demonstrated for noble-metal nanostructures of Au, Pt, Pd, Ir and their alloys [15, 16, 17, 18, 19, 20, 21], to the best of our knowledge, there is no literature report on Ru nanostructure-based peroxidase mimics. Ru is quite unique compared to other noble metals. For example, Ru is chemically super stable and is even invulnerable to aqua regia [28]; Ru is the only noble metal that normally takes the hexagonal close-packed (hcp) crystal structure [29]. These unique features of Ru inspired us to explore Ru nanostructure-based peroxidase mimics.

In this work, we demonstrate the peroxidase-like properties of Ru nanoframes with an octahedral shape and size <10 nm. Specifically, uniform Ru nanoframes were first synthesized using a method based on seeded growth and chemical etching [29]. The peroxidase-like activity of the frames was then demonstrated by the catalytic reactions between hydrogen peroxide and different peroxidase substrates. Using 3,3′,5,5′-tetramethylbenzidine (TMB [30]) as a model substrate, we have quantified the catalytic efficiency of the Ru frames. Finally, superior stabilities of the Ru frames as peroxidase mimics were demonstrated. This work represents the first attempt to explore Ru-based peroxidase mimics and, in a sense, offers a promising prospect for the application of Ru nanomaterials in biocatalysis.

2 Materials and methods

2.1 Chemicals and materials

Ruthenium (III) chloride hydrate (RuCl3·xH2O), sodium tetrachloropalladate(II) (Na2PdCl4, 98 %), potassium bromide (KBr, ≥99 %), l-ascorbic acid (AA, ≥99 %), poly(vinylpyrrolidone) (PVP, M W ≈ 55,000), hydrochloric acid (HCl, 37 %), iron(III) chloride (FeCl3, 97 %), 3,3′,5,5′-tetramethylbenzidine (TMB, >99 %), 3,30-diaminobenzidine (DAB, > 99 %), o-phenylenediamine (OPD, > 98 %), hydrogen peroxide solution (30 wt. % in H2O), sodium chloride (NaCl, 99.5 %), sodium phosphate dibasic (Na2HPO4, 99 %), potassium phosphate monobasic (KH2PO4, 99 %), tris base (99.9 %), citric acid (99 %), acetic acid (HOAc, 99.7 %), and sodium acetate (NaOAc, 99 %) were all obtained from Sigma-Aldrich. Ethylene glycol (EG) was obtained from J. T. Baker. All aqueous solutions were prepared using deionized (DI) water with a resistivity of 18.0 MΩ cm.

2.2 Preparation of Ru nanoframes

Ru nanoframes were prepared using our recently published procedure with minor modifications [29]. In brief, Ru was selectively deposited to the edge and corner sites of Pd truncated octahedra as the seeds, leading to the formation of Pd–Ru core-frame octahedra. The Pd cores were then removed through chemical etching, leaving Ru octahedral nanoframes as the final product. Specifically, three steps were involved in a standard synthesis:
  1. 1.

    Preparation of 5.6 nm Pd truncated octahedra to be used as the seeds. The Pd seeds were produced according to our previously published procedure [31]. The final Pd seeds were dispersed in 1.0 mL of EG for future use. Particle concentration for the Pd seeds was estimated to be 7.8 × 10−6 M (1 M = 1 mol L−1) with the combination of transmission electron microscope (TEM) imaging and ICP-OES analysis [31].

     
  2. 2.

    Deposition of Ru on Pd seeds. 8 mL of an EG solution containing 105 mg of PVP and 66.6 mg of AA was combined in a 50-mL three-neck flask and preheated to 200 °C in an oil bath under magnetic. Then, 1.0 mL of the already synthesized Pd seeds were added to the flask using a pipette. After 5 min, 10.0 mL of RuCl3·xH2O solution (0.4 mg/mL, in EG) was injected to the flask at a rate of 2.0 mL/h using a syringe pump. The products (i.e., Pd–Ru core-frame octahedra) were collected by centrifugation, washed once with acetone, twice with water, and finally re-dispersed in 1.0 mL of DI water.

     
  3. 3.

    Removal of Pd cores from Pd–Ru core-frame octahedra. KBr (200 mg), PVP (40 mg), FeCl3 (40 mg), HCl (0.2 mL, 37 %), DI water (3.8 mL), and an aqueous suspension of the as-prepared Pd–Ru core-frame octahedra (0.5 mL) were mixed together in a 20-mL glass vial under magnetic stirring at room temperature for 10 min. Then, the solution was heated to 80 °C in an oil bath under magnetic stirring. After 1 h, the solution was cooled down with a water bath to room temperature and the products (i.e., Ru frames) were collected by centrifugation, washed once with ethanol, twice with water, and finally re-dispersed in 0.5 mL of DI water or EG for future use.

     

2.3 Evaluation of the peroxidase-like activities of Ru frames

The experiments were performed at room temperature in 1.5 mL tubes. The catalytic reactions were carried out in different buffer solutions (i.e., 1.0 mL 0.2 M NaOAc/HOAc buffer solution pH 4.0 for TMB, 1.0 mL 0.2 M Na2HPO4 + 0.1 M citric acid buffer solution pH 7.8 for DAB, and 1.0 mL Tris–HCl + 0.15 M NaCl buffer solution pH 7.8 for OPD). Each contained ~1 × 10−11 M Ru frames, 2 M H2O2, and 0.8 mM TMB, DAB, or OPD. Control experiments were conducted under the same conditions except for the absence of Ru frames.

2.4 Kinetic assays

The steady-state kinetic assays [9, 20] were performed at room temperature (~22 °C) in 1.0 mL 0.2 M NaOAc/HOAc solution (pH 4.0). Upon the addition of substrates (TMB and H2O2) in the buffer system containing Ru frames (1.06 × 10−11 M), the absorbance at 653 nm of the reaction solution as a function of time were recorded using a spectrophotometer for 2 min (interval of 6 s). The initial reaction velocity (ν) was derived through ν = SlopeInitial/(ε TMB-653 nm × l), where SlopeInitial was obtained from the first derivation of each “absorbance vs. time” plots, ε TMB-653 nm was the molar extinction coefficient of TMB at 653 nm that equals 3.9 × 104 M−1 cm−1 [32], and l is the length of cuvettes that equals 1.0 cm. The “ν versus substrate concentrations” plots were then fitted with the Michaelis–Menten equation ν = V max × [S]/(K m + [S]), where V max represents the maximal reaction velocity, [S] is the substrate concentration, and K m is the Michaelis constant. Kinetic parameters K m and V max were determined from the double reciprocal plot (or Lineweaver–Burk plot [33]).

2.5 Characterizations

Transmission electron microscope images were taken using a JEOL JEM-2010 microscope. High-resolution TEM (HRTEM) and high-angle annular dark-field scanning TEM (HAADF-STEM) images were performed using a JEOL ARM200F with STEM Cs corrector operated at 200 kV. The UV–Vis spectra of the catalytic reaction solutions were recorded using an Agilent Cary 60 UV–Vis spectrophotometer. The concentrations of Pd ions were determined using an inductively coupled plasma-optical emission spectroscopy (ICP-OES, Perkin Elmer Optima 7000DV), which could be converted to the particle concentration of Pd once the particle shape and size had been resolved through TEM imaging. pH values of solutions were measured using an Oakton pH 700 Benchtop Meter. Photographs of samples in tubes were taken using a Canon EOS Rebel T5 digital camera.

3 Results and discussion

Figure 1 shows the TEM images of the Ru frames produced from a standard synthesis. As indicated by the low-magnification TEM image (Fig. 1a), the Ru frames were obtained with a high purity (>95 %) and good uniformity. The magnified TEM image in Fig. 1b clearly reveals the frame structure with an octahedral shape for the products. By randomly analyzing 200 individual particles, the average edge length and thickness of the Ru frames equaled 6.2 and 1.8 nm, respectively. The HRTEM and HAADF-STEM images shown in Fig. 1c and d clearly reveal the face-centered cubic (fcc) crystal structure and octahedral frame morphology for the Ru frames. The lattice spacing of Ru frame in Fig. 1c was determined to be 0.22 nm, which could be indexed to the {111} plane of face-centered cubic (fcc) Ru crystal structure. Since the Ru frames were grown from the ~5.6 nm Pd seeds with a well-defined truncated octahedral shape [29], the total amount of the frames produced from a standard synthesis should be equal to that of the initial Pd seeds, which was estimated to be 4.7 × 1015 particles/mL based on the inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis. Therefore, the particle concentration for the Ru frame suspension obtained from a standard synthesis was estimated to be 4.7 × 1015 particles/mL or 3.9 × 10−6 M. This data is essential to quantitative understanding of the peroxidase-like activity of the Ru frames (see more discussions below).
Fig. 1

Typical TEM images of Ru frames obtained in a standard synthesis. a Low-magnification TEM image showing the high yield and good uniformity of the sample. b TEM image at a higher magnification showing the frame structure with hollow interiors. c HRTEM image of an individual Ru frame orientated along <110> direction. The inset shows a 3D model of the sample. d HAADF-STEM image showing the 3D octahedral frame morphology of the sample

The peroxidase-like property of the Ru frames was demonstrated by catalyzing the oxidation of peroxidase substrates with hydrogen peroxide (H2O2). As shown in Fig. 2, Ru frames efficiently catalyze the oxidation of TMB (a typical peroxidase substrate [34]) by H2O2, generating blue-colored oxidized TMB with characteristic absorption peaks at 371, 653, and 892 nm (Fig. 2b) [34]. The reaction rate was directly proportional to the particle concentration of Ru frames in the reaction solution (Fig. 2c). In addition to TMB, the Ru frames could also rapidly catalyze the oxidation of other peroxidase substrates such as 3,3′-diaminobenzidine (DAB) and o-phenylenediamine (OPD) [9, 35], yielding brown- and light orange-colored products, respectively (Fig. 2a). These observations clearly demonstrate the peroxidase-like activity of the Ru frames.
Fig. 2

(Color online) Peroxidase-like activity of Ru frames. a A digital photograph taken at the reaction time t = 5 min, demonstrating the capability of Ru frames as peroxidase mimics in catalyzing the oxidation of different substrates (i.e., TMB, DAB, and OPD) by H2O2. b UV–Vis spectrum of the TMB-H2O2 reaction system catalyzed by Ru frames (1.0 × 10−11 M). c Time- and particle concentration-dependent absorbance at 653 nm measured from the reaction solutions containing TMB (0.8 mM), H2O2 (2.0 M), and Ru frames with different concentrations in 0.2 M HOAc/NaOAc buffer (pH 4.0) at room temperature

We also evaluated the effects of various reaction conditions on the catalytic activity of the Ru frames using the oxidation of TMB by H2O2 as a model reaction. We chose to focus on this reaction because its mechanism has been well understood in previous studies and TMB is less toxic compared to other substrates [34]. As shown in Fig. 3, the catalytic efficiency of the Ru frames (1.0 × 10−11 M in particle concentration) had a strong dependent on pH, temperature, and concentrations of TMB and H2O2. Taken all the factors together, the optimal conditions for maximized reaction rate were found to be roughly pH 4.0, 40 °C, 0.8 mM TMB, and 6.0 M H2O2. Since no significant change of catalytic efficiency for temperatures at 20–40 °C (Fig. 3b) and H2O2 concentrations at 2.0–8.0 M (Fig. 3d), for simplicity, we adopted pH 4.0, room temperature (~22 °C), 0.8 mM TMB, 2.0 M H2O2, and 1.0 × 10−11 M Ru frames as the standard conditions for subsequent experiments.
Fig. 3

The effects of (a) pH, (b) temperature, (c) TMB concentration, and (d) H2O2 concentration on the catalytic activity of Ru frames. The experiments were carried out in aqueous solution in the presence of 1.0 × 10−11 M Ru frames as the catalysts. Other reaction conditions were 0.2 M HOAc/NaOAc buffer (pH 4.0), 2.0 M H2O2, 0.8 mM TMB, and room temperature, unless otherwise stated. The maximum absorbance at 653 nm of reaction solutions at t = 5 min in each plot (ad) was set as 100 %

To quantitatively understand the catalytic activity of the Ru frames, we determined the apparent steady-state kinetic parameters for the catalytic reaction between TMB and H2O2 [34]. Basically, the initial reaction velocity was determined by quantifying the concentration of colored product (i.e., oxidized TMB with a maximum absorbance at 653 nm [34, 36]) as a function of time with the aid of a spectrophotometer (experimental details were provided in Sect. 2). As shown in Fig. 4, typical Michaelis–Menten curves were observed for both TMB (Fig. 4a) and H2O2 (Fig. 4c) when the initial reaction velocities were plotted against the concentrations of H2O2 and TMB, respectively. The curves could then be fitted to the double-reciprocal or Lineweaver–Burk plots [33] (Fig. 4b, d). From the double-reciprocal plots, the kinetic parameters for Ru frames were determined and summarized in Table 1. For comparison, we also determined the kinetic parameters of initial 5.6 nm Pd octahedral seeds and listed those of HRP from Ref. [9] in Table 1. It can be seen that the catalytic efficiencies (in terms of catalytic constant, K cat, which is defined as the maximum number of chemical conversions of substrate molecules per second per catalyst [37]) of the Ru frames toward TMB and H2O2 were approximately three and two times higher than those of HRP, respectively. Note that the catalytic efficiencies of Ru frames were also several times higher than initial Pd octahedral seeds (Table 1). Since colored products are originated from TMB, it can be concluded that the Ru frames are about three times more efficient in generating a detectable color signal. The Michaelis constant K m (which measures the substrate concentration at which the reaction velocity is half of the maximum velocity, V max) [37] toward TMB for Ru frames was seven times lower than that for HRP, implying that Ru frames had a higher affinity for TMB than HRP. In contrast, the K m toward H2O2 for Ru frames was eighty-six times higher than that for HRP, suggesting a lower affinity for Ru frames in binding to H2O2 as compared to HRP. To examine possible changes of crystal structure for the Ru nanoframes during the catalytic reaction, we analyzed individual frames before and after the catalysis by HRTEM. As indicated by the HRTEM images and corresponding Fourier transform patterns shown in Fig. 5, the fcc crystal structure for Ru frames was well retained after the catalytic reaction.
Fig. 4

Kinetic assays of Ru frames as catalysts for the oxidation of TMB by H2O2. The initial reaction velocity (ν) was measured under standard conditions. Error bars indicate the standard deviations of three independent measurements. a Plot of ν against TMB concentration, in which H2O2 concentration was fixed at 2.0 M; b double-reciprocal plot generated from (a); c plot of ν against H2O2 concentration, in which TMB concentration was fixed at 0.8 mM; d double-reciprocal plot generated from (c)

Table 1

Comparison of kinetic parameters of Ru frames and HRP toward the oxidation of TMB by H2O2

Catalyst

[E] (M)

Substrate

K m (M)

V max (M s−1)

K cat (s−1)

Ru frames

1.06 × 10−11

TMB

6.03 × 10−5

1.34 × 10−7

1.26 × 104

1.06 × 10−11

H2O2

3.18 × 10−1

7.41 × 10−8

6.98 × 103

Pd seeds

1.06 × 10−10

TMB

4.7 × 10−5

3.8 × 10−7

3.6 × 103

1.06 × 10−10

H2O2

7.3 × 10−1

1.4 × 10−7

1.3 × 103

HRP

2.5 × 10−11

TMB

4.3 × 10−4

1.0 × 10−7

4.0 × 103

2.5 × 10−11

H2O2

3.7 × 10−3

8.7 × 10−8

3.5 × 103

[E] represents the catalyst concentration, K m is the Michaelis constant, V max is the maximal reaction velocity, and K cat is the catalytic constant that equals V max/[E]

Fig. 5

Representative HRTEM images of indivudal Ru frames a before and b after they had been used as catalysts for the oxidation of TMB by H2O2. Insets are corresponding Fourier transform patterns

Finally, we evaluated the stability for the Ru frames as peroxidase mimics. It should be noted that stability is a key parameter for a peroxidase mimic because it largely determines the durability and reproducibility of the mimic in certain applications. To test the chemical stability, we incubated Ru frames in solutions of different pH ranging from 0 to 12 for a period of 2 h prior to the measurement of their catalytic activities. As shown in Fig. 6a, the catalytic activity of the Ru frames was fairly stable even though they had been treated with strong acid or base, indicating their outstanding chemical stabilities. We also evaluated the thermal stability of Ru frames by heating them at different temperatures. As shown in Fig. 6b, their catalytic activity essentially kept unchanged after they had been heated for 2 h at temperatures up to 200 °C. The observed stable catalytic performance of the Ru frames might be attributed to their inherent inertness (e.g., ultrahigh resistance to oxidative etching) and the excellent thermal stability of elemental Ru (e.g., with an ultra-high melting point of >2,000 °C) [28, 38].
Fig. 6

a Chemical and b thermal stability tests for the Ru frames in catalyzing the oxidation of TMB by H2O2. In a, Ru frames (3.9 × 10−8 M, in deionized water) were first incubated in solutions with pH of 0 to 12 for 2 h. Their relative catalytic activities (i.e., absorbance at 653 nm of reaction solutions at t = 5 min, standard conditions) were then measured, in which the activity at pH 4.0 was set as 100 %; In (b), Ru frames (3.9 × 10−8 M, in ethylene glycol) were heated at temperatures of 40 to 200 °C for 2 h. Their relative catalytic activities were then measured under standard conditions, in which the activity at room temperature (~22 °C) was set as 100 %

4 Conclusions

In conclusion, we have demonstrated a new kind of peroxidase mimic—Ru nanoframes of sub-10 nm in size. The Ru frames could be produced in a high purity and good uniformity. The catalytic efficiency of the Ru frames was found to be higher than that of natural peroxidase. In addition, the frames displayed excellent chemical and thermal stabilities. This work represents the first demonstration of Ru nanostructure-based peroxidase mimics, and thus opens up a new avenue for exploring the bio-applications of Ru nanomaterials.

Notes

Acknowledgments

This work was partially supported by startup funds from Michigan Technological University, and the Michigan Translational Research & Commercialization Fund (MTRAC), Grant Case-48161 of the 21st Century Jobs Trust Fund received through the Michigan Strategic Fund from the State of Michigan. The MTRAC program is funded by the Michigan Strategic Fund with program oversight by the Michigan Economic Development Corporation.

Conflict of interest

The authors declare that they have no conflict of interest.

References

  1. 1.
    Wei H, Wang E (2013) Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes. Chem Soc Rev 42:6060–6093CrossRefPubMedGoogle Scholar
  2. 2.
    Kotov NA (2010) Inorganic nanoparticles as protein mimics. Science 330:188–189CrossRefPubMedGoogle Scholar
  3. 3.
    Lin Y, Ren J, Qu X (2014) Catalytically active nanomaterials: a promising candidate for artificial enzymes. Acc Chem Res 47:1097–1105CrossRefPubMedGoogle Scholar
  4. 4.
    Breslow R (1995) Biomimetic chemistry and artificial enzymes: catalysis by design. Acc Chem Res 28:146–153CrossRefGoogle Scholar
  5. 5.
    Li W, Qu X (2015) Cancer biomarker detection: recent achievements and challenges. Chem Soc Rev 44:2963–2997CrossRefGoogle Scholar
  6. 6.
    Xianyu Y, Wang Z, Jiang X (2014) A plasmonic nanosensor for immunoassay via enzyme-triggered click chemistry. ACS Nano 8:12741–12747CrossRefPubMedGoogle Scholar
  7. 7.
    Cheng H, Zhang L, He J et al (2016) Integrated nanozymes with nanoscale proximity for in vivo neurochemical monitoring in living brains. Anal Chem 88:5489–5497CrossRefPubMedGoogle Scholar
  8. 8.
    Wang X, Hua Y, Wei H (2016) Nanozymes in bionanotechnology: from sensing to therapeutics and beyond. Inorg Chem Front 3:41–60CrossRefGoogle Scholar
  9. 9.
    Gao L, Zhuang J, Nie L et al (2007) Intrinsic peroxidase-like activity of ferromagnetic nanoparticles. Nat Nanotechnol 2:577–583ADSCrossRefPubMedGoogle Scholar
  10. 10.
    Zhang X, Gong S, Zhang Y et al (2010) Prussian blue modified iron oxide magnetic nanoparticles and their high peroxidase-like activity. J Mater Chem 20:5110–5116CrossRefGoogle Scholar
  11. 11.
    Liu X, Wang Q, Zhao H et al (2012) BSA-templated MnO2 nanoparticles as both peroxidase and oxidase mimics. Analyst 137:4552–4558ADSCrossRefPubMedGoogle Scholar
  12. 12.
    André R, Natálio F, Humanes M et al (2011) V2O5 nanowires with an intrinsic peroxidase-like activity. Adv Funct Mater 21:501–509CrossRefGoogle Scholar
  13. 13.
    Xiao X, Luan Q, Yao X et al (2009) Single-crystal CeO2 nanocubes used for the direct electron transfer and electrocatalysis of horseradish peroxidase. Biosens Bioelectron 24:2447–2451CrossRefPubMedGoogle Scholar
  14. 14.
    Wei H, Wang E (2008) Fe3O4 magnetic nanoparticles as peroxidase mimetics and their applications in H2O2 and glucose detection. Anal Chem 80:2250–2254CrossRefPubMedGoogle Scholar
  15. 15.
    Su H, Liu DD, Zhao MM et al (2015) Dual-enzyme characteristics of polyvinylpyrrolidone-capped iridium nanoparticles and their cellular protective effect against H2O2-induced oxidative damage. ACS Appl Mater Inter 7:8233–8242CrossRefGoogle Scholar
  16. 16.
    Gao Z, Hou L, Xu M et al (2014) Enhanced colorimetric immunoassay accompanying with enzyme cascade amplification strategy for ultrasensitive detection of low-abundance protein. Sci Rep 4:3966ADSPubMedPubMedCentralGoogle Scholar
  17. 17.
    He W, Wu X, Liu J et al (2010) Design of AgM bimetallic alloy nanostructures (M = Au, Pd, Pt) with tunable morphology and peroxidase-like activity. Chem Mater 22:2988–2994CrossRefGoogle Scholar
  18. 18.
    Jv Y, Li B, Cao R (2010) Positively-charged gold nanoparticles as peroxidiase mimic and their application in hydrogen peroxide and glucose detection. Chem Commun 46:8017–8019CrossRefGoogle Scholar
  19. 19.
    Fan J, Yin J, Ning B et al (2011) Direct evidence for catalase and peroxidase activities of ferritin–platinum nanoparticles. Biomaterials 32:1611–1618CrossRefPubMedGoogle Scholar
  20. 20.
    Xia X, Zhang J, Lu N et al (2015) Pd-Ir core-shell nanocubes: a type of highly efficient and versatile peroxidase mimic. ACS Nano 9:9994–10004CrossRefPubMedGoogle Scholar
  21. 21.
    Manea F, Houillon FB, Pasquato L et al (2004) Nanozymes: gold-nanoparticle-based transphosphorylation catalysts. Angew Chem Int Ed 43:6165–6169CrossRefGoogle Scholar
  22. 22.
    Shi W, Wang Q, Long Y et al (2011) Carbon nanodots as peroxidase mimetics and their applications to glucose detection. Chem Commun 47:6695–6697CrossRefGoogle Scholar
  23. 23.
    Wang X, Qu K, Xu B et al (2011) Multicolor luminescent carbon nanoparticles: synthesis, supramolecular assembly with porphyrin, intrinsic peroxidase-like catalytic activity and applications. Nano Res 4:908–920CrossRefGoogle Scholar
  24. 24.
    Song Y, Qu K, Zhao C et al (2010) Graphene oxide: intrinsic peroxidase catalytic activity and its application to glucose detection. Adv Mater 22:2206–2210CrossRefPubMedGoogle Scholar
  25. 25.
    Cui R, Huang H, Yin Z et al (2008) Horseradish peroxidase-functionalized gold nanoparticle label for amplified immunoanalysis based on gold nanoparticles/carbon nanotubes hybrids modified biosensor. Biosens Bioelectron 23:1666–1673CrossRefPubMedGoogle Scholar
  26. 26.
    Lei CX, Hu SQ, Shen GL et al (2003) Immobilization of horseradish peroxidase to a nano-Au monolayer modified chitosan-entrapped carbon paste electrode for the detection of hydrogen peroxide. Talanta 59:981–988CrossRefPubMedGoogle Scholar
  27. 27.
    Love JC, Estroff LA, Kriebel JK et al (2005) Self-assembled monolayers of thiolates on metals as a form of nanotechnology. Chem Rev 105:1103–1169CrossRefPubMedGoogle Scholar
  28. 28.
    Balcerzak M, Kaczmarczyk M (2001) Rapid derivative spectrophotometric method for the determination of platinum in Pt-Ru/C catalyst using iodide media. Anal Sci 17:1321–1324CrossRefPubMedGoogle Scholar
  29. 29.
    Ye H, Wang Q, Catalano M et al (2016) Ru nanoframes with an fcc structure and enhanced catalytic properties. Nano Lett 16:2812–2817ADSCrossRefPubMedGoogle Scholar
  30. 30.
    Porter DJT, Bright JH (1982) The horseradish peroxidase-catalyzed oxidation of 3,5,3′,5′-tetramethylbenzidine. J Biol Chem 258:9913–9924Google Scholar
  31. 31.
    Xia X, Figueroa-Cosme L, Tao J et al (2014) Facile synthesis of iridium nanocrystals with well-controlled facets using seed-mediated growth. J Am Chem Soc 136:10878–10881CrossRefPubMedGoogle Scholar
  32. 32.
    Karaseva EI, Losev YP, Metelitsa DI (2002) Peroxidase-catalyzed Oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of 2,4-dinitrosoresorcinol and polydisulfide derivatives of resorcinol and 2,4-dinitrosoresorcinol. Russ J Bioorg Chem 28:128CrossRefGoogle Scholar
  33. 33.
    Lineweaver H, Burk D (1934) The determination of enzyme dissociation constants. J Am Chem Soc 56:658–666CrossRefGoogle Scholar
  34. 34.
    Josephy PD, Eling TE, Mason RP (1982) The horseradish peroxidase-catalyzed oxidation of 3,5,3′,5′-tetramethylbenzidine. Free radical and charge-transfer complex intermediates. J Biol Chem 257:3669–3675PubMedGoogle Scholar
  35. 35.
    Cai Q, Lu S, Liao F et al (2014) Catalytic degradation of dye molecules and in situ SERS monitoring by peroxidase-like Au/CuS composite. Nanoscale 6:8117–8123ADSCrossRefPubMedGoogle Scholar
  36. 36.
    Frey A, Meckelein B, Externest D et al (2000) A stable and highly sensitive 3,5,3′,5′-tetramethylbenzidine-based substrate reagent for enzyme-linked immunosorbent assays. J Immunol Methods 233:47–56CrossRefPubMedGoogle Scholar
  37. 37.
    Hagen J (2006) Industrial catalysis: a practical approach. Wiley-VCH, WeinheimGoogle Scholar
  38. 38.
    Pan C, Pelzer K, Philippot K (2001) Ligand-stabilized ruthenium nanoparticles: synthesis, organization, and dynamics. J Am Chem Soc 123:7584–7593CrossRefPubMedGoogle Scholar

Copyright information

© Science China Press and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Haihang Ye
    • 1
  • Jacob Mohar
    • 1
  • Qingxiao Wang
    • 2
  • Massimo Catalano
    • 2
  • Moon J. Kim
    • 2
  • Xiaohu Xia
    • 1
  1. 1.Department of ChemistryMichigan Technological UniversityHoughtonUSA
  2. 2.Department of Materials Science and EngineeringUniversity of Texas at DallasRichardsonUSA

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