Intermetallic PtPb Nanoplates Composites for Boosting

Subscriber access provided by University of Newcastle, Australia

Article

Graphene/Intermetallic PtPb Nanoplates Composites for Boosting Electrochemical Detection of H2O2 Released from Cells Yingjun Sun, Mingchuan Luo, Xiangxi Meng, Jing Xiang, Lei Wang, Qiushi Ren, and Shaojun Guo Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.7b00248 • Publication Date (Web): 16 Feb 2017 Downloaded from http://pubs.acs.org on February 18, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Analytical Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Analytical Chemistry

Graphene/Intermetallic

PtPb

Nanoplates

Composites

for

Boosting

Electrochemical Detection of H2O2 Released from Cells Yingjun Sun+‡, Mingchuan Luo+, Xiangxi Meng,§ Jing Xiang,§ Lei Wang,‡ Qiushi Ren,§ Shaojun Guo+*# +Department

of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871,

China. ‡ College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, P. R. China. §

Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China.

#

BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China.

ABSTRACT Rational design and construction of electrocatalytic nanomaterials is vital for improving the sensitivity and selectivity of non-enzymatic electrochemical sensors. Here, we report a novel graphene supported intermetallic PtPb nanoplates (PtPb/G) nanocomposite as enhanced electrochemical sensing platform for high-sensitivity detection of H2O2 in neutral solution and also released from the cells. The intermetallic PtPb nanoplates are first synthesized via a simple wet-chemistry process, and subsequently assembled on graphene via a solution-phase self-assembly approach. The obtained nanocomposite exhibits excellent electrocatalytic activity for the electrochemical reduction of H2O2 in a half-cell test, and can detect H2O2 with a wide linear detection range of 2 nM to 2.5 mM and a very low detection limit of 2 nM. Under the same condition, the sensitivity of PtPb/G for the detection of H2O2 is more than 12.7 times higher than that of commercial Pt/C. The high-density of electrocatalytic active sites on the unique PtPb nanoplates and the synergistic effect between PtPb nanoplates and graphene appear to be the main factors in contributing the outstanding electroanalytical performance. The PtPb/G can be also used for the practical detection of H2O2 released from Raw 264.7 cells. KEYWORDS: nanoplate; graphene; sensors; hydrogen peroxide; cells

INTRODUCTION

Hydrogen peroxide (H2O2) is one of the most general yet important molecules existed in different biological tissues.1-3 Maintaining the H2O2 concentration at a normal level is critical to achieve the normal physiological 1 / 19

ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

activities of cells, otherwise might trigger diseases like angiocardiopathy, tumor, neurodegeneration and so on.4,5 As a result, it is very important to develop detective technologies to effectively and accurately monitor the H2O2 concentration in a living cell, prior to taking the subsequently balancing steps. To date, numerous methods such as fluorescenct,6 photocolorimetric,7 chemiluminescenct8 and electrochemical9 ones have been developed for the effective detection of H2O2. Among them, the electrochemical sensor is considered as the most promising technique, due to its high sensitivity, low detection limit, as well as high convenience.10,11 Depending on whether the enzymes exist or not, the electrochemical H2O2 sensors can be subdivided into two categories, i.e. enzymatic and nonenzymatic sensors.12 Although the enzymes, such as the horseradish peroxidase (HRP),13 have shown impressive selectivity in the conventional electrochemical detection of H2O2, they generally suffer from low durability due to their sensitivity to ambition conditions, rendering them difficulty and expensive in practical applications.14 Alternatively, efforts have been devoted to replacing the enzymes with low-cost and robust inorganic nanocatalysts, including precious metals,15 non-precious metals,16 metal-free carbon-based materials17 and so on. Among them, nanocomposites based on Pt18 and PtM alloys (M represents other transition metals)19 were widely used as non-enzymatic sensors due to their high sensitivity and capability of practically detecting H2O2 in cells. Impressive performance has been achieved in these Pt-based electrochemical sensors, including Pt-graphene,20 dumbbell-like PtPd-Fe3O4,4 Pt-carbon nanotube,21 PtAu-graphene-carbon nanotube22 and so on. However, there are two limitations, which constrain the further application of these Pt-based electrochemical sensors: (1) it is usually challenge to meet the detective limit as low as nM in a living cell by using currently available Pt-based composites; (2) these sensors normally show poor selectivity to H2O2 due to the undesirably high sensitivity of Pt to other interfering molecules.23,24 To address these issues, we herein report a new class of Pt-based nanomaterials composed of intermetallic PtPb nanoplates25 and graphene as enhanced electrochemical sensing platform for the high-sensitivity detection of H2O2. Herein, graphene was chosen as the supporting material not only because of its large surface area and high conductivity, but also due to the facility for assembling target metal nanostructures on the surface.26-29 However, to the best of our knowledge, there are no reports on combining 2D metallic nanostructures with graphene for constructing high-sensitivity biosensors, probably due to the great challenges in synthesizing 2D metallic nanostructures. Based on the superior electrocatalytic performance of nanoplates,30,31 the intermetallic PtPb nanoplates are first assembled on graphene as an effective electrode materials to construct a high-sensitivity H2O2 2 / 19


Page 2 of 19

Page 3 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


sensor in this work. The monodisperse, ultra-thin PtPb nanoplates are able to guarantee vast active sites and strong interaction with support, which can boost enhance the performance of electroanalysis. Our experiments show that this biosensor indeed displays very high sensitivity and selectivity toward the reduction of H2O2 with a low detection of 2 nM at −0.2 V vs Ag/AgCl, and we also demonstrate the optimized PtPb/G is successfully used to detect the trace amount of H2O2 released from Raw 264.7 cells.

EXPERIMENTAL SECTION Regents and Materials. Platinum ( ) acetylacetonate (Pt(acac)2), lead ( ) acetylacetonate (Pb(acac)2), oleylamine (OAm), 1-octadecene (ODE), N-formylmethionyl-leucyl-phenylalanine (fMLP) were all purchased from SigmaAldrich. L-ascorbic acid (L-AA), acetic acid and isopropanol were obtained from J&K Scientific. The commercial Pt/C catalyst (20 wt%) was obtained from Johnson-Matthey. Ethanol, cyclohexane, ammonia solution (25 wt%), hydrogen peroxide

(H2O2)

were

supplied

by

Beijing

Tongguang

Fine

Chemicals

Company.

Sodium dihydrogen phosphate (NaH2PO4), disodium hydrogen phosphate (Na2HPO4), sodium chloride (NaCl) and potassium chloride (KCl) were provided by Xilong Chemical Factory Co, Ltd. N-N-dimethylformamide (DMF) was purchased from Tianjin Kangkede technology Co, Ltd and Nafion (5%) was bought from Alfa Aesar. Iron ( ) chloridehexahyclrate (K3[Fe(CN)6]), L-Cysteine (L-Cys), glucose (GLU), uric acid (UA) were obtained from Sinopharm Chemical Regent Co, Ltd. A 0.1 M phosphate buffer solution (PBS, pH 7.4) containing NaH2PO4, Na2HPO4 and NaCl was used as the electrolyte in the electrochemical experiment. All regents were used without further purification and all solutions were freshly prepared with ultrapure water (18.2 MΩ/cm). Apparatus. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) images were taken from a Tecani-G2 T20 operating at 200 KV. The concentration of catalysts were determined by the inductively coupled plasma mass spectrometry (ICP-MS) on a Prodigy. Synthesis of PtPb nanoplates. The PtPb nanoplates were synthesized as reported with a slight modification.25 10 mg Pt(acac)2, 8 mg Pb(acac)2, 35.6 mg L-AA, 2.5 mL OAm and 2.5 mL ODE were fist added into a 25 mL roundbottomed flask and capped with a stopper-rubber. Then the mixture was ultrasound for 1 h to get a transparent solution. Subsequently, the resulting solution was heated from room temperature to 160 oC at 3 oC min−1 and kept that temperature for 5 h. Before it was naturally cooled to temperature, the black colloidal products were collected by centrifugation and washed three times with an ethanol/cyclohexane mixture. 3 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Synthesis of grapheme (G). The graphite oxide (GO) was synthesized according to the modified Hummers method.32 Then, 40 mg of GO was dispersed in 80 mL DMF solution by sonication. Then, 2 mL ammonium solution was added into the above solution, and the resulting solution was refluxed at 150 oC for 6 h to convert GO to G. After cooled down to room temperature, the solution color turned brown to black.33 Synthesis of PtPb/G composites. The PtPb nanoplates (0.7 mg/mL) dispersed in 10 mL of cyclohexane and G (0.5 mg/mL) dispersed in 10 mL of DMF were then mixture and ultrasound for 1 h. Then, 6 mL of ethanol was added, and the as-obtained PtPb/G was collected by centrifugation for 10 min at 9500 rpm. The PtPb/G was dried under ambient conditions for further use. Catalyst Preparation. The PtPb/G was cleaned with a mixture of 10 mL acetic acid and 10 mL ethanol to remove residual OAm. After sonicating for 20 min, the solution was transferred to stirring for 1 h under ambient conditions. The catalyst was separated by centrifugation and washed with ethanol three times before it was redispersed in a mixture of solvents containing water, isopropanol and Nafion (5%) (v/v/v = 1/1/0.005) to form a 2 mg/mL suspension. The commercial Pt/C and G were also dispersed in the above solution to form 2 mg/mL suspension as comparison. Electrochemical measurements. Electrochemical experiments were performed with a CHI760 Electrochemical Workstation (Shanghai Chenhua Instrument Corporation, China) in a conventional three-electrode cell. The modified glass carbon electrode (GCE), Ag/AgCl, Pt wire were used as the working electrode, reference electrode and counter electrode, respectively. Before the measurement, the GCE (3 mm) was carefully polished with 0.5 μm and 50 nm Al2O3 powder, cleaned by ultra-pure water, sonicated in water, and dried under high-purity nitrogen blow. 3 μL of the catalyst ink was dropped onto the GCE surface and dried at ambient condition. The G modified GCE (G/GCE) and the commercial Pt/C-modified GCE ((Pt/C/GCE) were prepared in the same way. All solutions were purged with high-purity nitrogen for at least 20 min to remove residential oxygen and cleaned in 0.1 M PBS (pH 7.4) by prescanning between −0.6 V and 0.6 V for 200 cycles at a scan rate of 500 mV/s under a saturated N2 atmosphere. Measuring the H2O2 released from cells of Raw 264.7. The Raw 264.7 cells were purchased from China Infrastructure of Cell Line Resource and grown in 5% CO2 in 75 cm2 flasks. They were collected by centrifugation and washed with PBS three times after growing to 90% confluence. The number of the cells was counted by a hemocytometer. The final packed cells were redispersed in 30 mL PBS (pH = 7.4) for the real-time electrochemical experiments at an applied potential of −0.2 V vs Ag/AgCl. 0.3 μM N-formylmethionyl-leucyl-phenylalanine (fMLP) 4 / 19


Page 4 of 19

Page 5 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


was added as a stimulant, making the cells release H2O2. As a comparison, the fMLP was also injected into the PBS without cells.

RESULTA AND DISCUSSION The morphology and structure of the obtained PtPb alloys were investigated by TEM and HRTEM (Figure 1). Transmission electron microscopy (TEM, Figure 1a and 1b) confirmed the PtPb alloy takes a hexagonal nanoplate shape, with an average edge length of 18 nm and average thickness of 5 nm (as measured from the vertical nanoplates on the grid). A closer observation from high-resolution TEM (HRTEM, Figure 1c) showed that the atomic arrangement along the edge is obviously different from that on the center facet. The fast Fourier transform (FFT) of partial area in nanoplate (Figure c1-c2) clearly indicate that the nanoplate owns a core/shell structure with an intermetallic PtPb core and a Pt shell. The center facet showed well-resolved lattice fringes with a spacing of 0.212 nm, ascribed to the PtPb (110) facet. To perform the subsequent electrochemical tests, the obtained PtPb nanoplates were assembled on graphene via a solution-phase self-assembly approach (see Experimental section for details). The PtPb nanoplates were well dispersed on the surface of graphene (Figure 1d). Before the electrochemical oxidation of H2O2, the Fe(CN)63−/4 redox probe was selected to characterize the surface properties of bare glassy carbon electrode (GCE), graphene on GCE (G/GCE), and PtPb/G on GCE (PtPb/G/GCE). The cyclic voltammograms (CVs) were carried out in 0.1 M KCl solution containing 5 mM K3[Fe(CN)6]. All three electrodes showed the well-defined quasi-reversible redox peaks of ferricyanide ions (Figure 2a). Notably, the peak current increases in the following sequence: GCE < G/GCE < PtPb/G/GCE, suggesting that: (1) the presence of G facilitates the electron transfer to Fe(CN)63−/4 redox pairs due to its high conductivity; (2) the introduction of 2D PtPb nanoplates further enlarges the electroactive surface area (ESA) on the electrode. Indeed, significant enhancements in ESA were further quantitated by the Randled-Sevcik equation34: Ip

2.69

105AD1/2n3/2γ1/2C

Where A is the area of the electroactive surface area (cm2), D is the diffusion coefficient (cm2s−1), n is the number of electrons transferred, γ is the scan rate (Vs−1), and C is the bulk concentration of the redox probe (mol cm−3). The ESA of PtPb/G/GCE was determined to be 0.1260 cm2, which is around 2 and 1.5 times higher than that of GCE (0.0623 cm2) and G/GCE (0.0831 cm2), respectively. Figure 2b compared the typical CVs of the aforementioned electrodes and commercial Pt/C electrode for H2O2 reduction in N2-saturated 0.1 M phosphate buffered saline (PBS, 5 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

pH＝7.4) containing 10 mM H2O2. As judged from the measured current and onset potential for H2O2 reduction, the PtPb/G/GCE showed much higher activity over other investigated electrodes, with peak current around two times higher than that of the commercial Pt/C electrode. To verify the sensitivity of PtPb/G/GCE towards H2O2 reduction, the CVs were recorded in different H2O2 concentrations range from 0 to 3 mM (Figure 3a). Upon stepwisely adding the amounts of H2O2, both the anodic oxidation current and the catholic oxidation current increased. However, the reduction current increased much slower than the oxidation current, rendering the former more sensitive in the detection of H2O2. Furthermore, a good linear relationship was observed when plotting the peak reduction current as a function of the H2O2 concentration (Figure 3b), indicating fairly good response. We then investigated the effect of scan rates on the recorded CVs to understand the charge transport behavior on the PtPb/G/GCE. As shown in Figure 3c, both the anodic and catholic currents increase with the applied scan rates, while the peak potential showed little dependence. Moreover, the peak currents are proportional to the square root of the scan rate (Figure 3d), indicating fast electron transfer kinetics on PtPb/G/GCE and a typical diffusion controlled process. To acquire the optimum potential for electrochemical detection of H2O2, the amperometric response under different potentials (from –0.4 to 0.1 V vs Ag/AgCl) were studied as the successive additions of 0.2 mM H2O2 (Figure 4a). The recorded current responds extremely fast to the variations in the concentration of H2O2, and reaches the steady state within 2s after each addition, indicating the rapid absorption and activation of H2O2 molecule on the electrode surface. The calibration curves for the current-concentration correlation showed that the linear relationship exists over a wide range of applied potentials (Figure 4b), demonstrating the broad region of available potentials for detecting H2O2. Based on the above results, the potential of −0.2 V was chosen to be the optimum potential. Then, the detection sensitivity on different modified electrodes was further examined. Figure 4c compared the current response of G, commercial Pt/C and PtPb/G on GCE with continuous injection of 0.2 mM H2O2 in buffer solution at −0.2 V. As H2O2 was added, the PtPb/G/GCE responded rapidly to the substrate and exhibited higher current than Pt/C/GCE. Furthermore, there was almost no current response to H2O2 on G/GCE. The sensitivity of G/PtPb (4.05 mA cm−2mM−1) is more than 12.7 times higher than that of commercial Pt/C (0.320 mA cm−2mM−1) (Figure 4d). The reasons why G/PtPb shows much higher sensitivity for H2O2 detection are that 2D bimetallic PtPb nanoplates themselves have very high electrocatalytic activity for H2O2 reduction than commercial Pt, and also graphene can greatly enhance the electron transfer during the H2O2 catalysis process. These results further reveal the excellent 6 / 19


Page 6 of 19

Page 7 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


properties of PtPb/G as a promising catalyst in H2O2 electrochemical sensors. The i-t measurements were carried out to evaluate the detection sensitivity of PtPb/G/GCE for H2O2 at a potential of –0.2 V, (Figure 5a). The result showed that with the injection of H2O2, the current on PtPb/G steadily increases. Meanwhile, the steady-state current can be achieved within several seconds, demonstrating its rapid electrochemical response to H2O2. The amplified graph of the red circled region was shown in Figure 5b, from which we observed the PtPb/G took steep and stable amperometric responses after each small injection of H2O2. The detection limit towards H2O2 using PtPb/G as the enhanced sensing platform was determined to be 2 nM, which enabled the detection at physiological level.4 The detection limit of H2O2 using PtPb/G was significantly lower than those of other reports related to noble metal-based electrochemical sensors, such as the Pt/graphene (0.2 μM),20 the dumbbell-like PtPdFe3O4 nanoparticles (5 nM),4 the PtAu/graphene-multiwalled carbon nanotubes electrode (0.6 μM),22 etc (Table 1).The typical detection current as a function of H2O2 concentration (range from 2 nM to 2.5 mM) was shown in Figure 5c. Firstly, the PtPb/G/GCE sensor showed fairly good response not only in high concentration (mM level) but also in extremely low concentration (nM level). Then, the obtained fitting curve in Figure 5c clearly displayed three similar linear regions (amplified in Figure 5d-f). The reason for three linear regions herein was probably caused by the different H2O2 absorption and activation behavior on G/PtPb catalyst under different H2O2 concentration, as demonstrated in previous report on PtPb-Fe3O4 dumbbell-like nanoparticle catalyst for H2O2 detection.4 The sensitivity was determined to be 1.82, 0.91, and 4.13 mA cm−2 mM−1 for the concentration range from 0.002 to 0.236 μM, from 0.236 to 11.34 μM, and from 11.34 to 2516 μM, respectively. A facile comparison with other electrochemical H2O2 sensors reported was summarized in Table 1, revealing the great potential of 2D PtPb/G as a new kind of electrochemical nanocatalysts for H2O2 detection. The excellent sensing performance can be attributed to the following structural properties of 2D PtPb/G: (1) the 2D nature of PtPb nanoplates and graphene offers much enhanced electroactive sites for the adsorption and reaction of H2O2; (2) more contact sites between 2D PtPb nanoplates and 2D graphene, compared to the conventional composite of 0D nanoparticles and 2D graphene, enable not only faster electron transfer on the electrode but also stronger synergistic effect to boost the interaction with H2O2. A big problem associated with the practical application of Pt-based H2O2 sensors is the poor selectivity, because Pt behaves like a “universal” catalytic material.23 In practical, various interfering species tend to be adsorbed onto the surface of Pt, and subsequently oxidized/reduced, thus generating current interferences for H2O2 detection. To assess the selectivity, the chronoamperometric measurement was conducted on the PtPb/G in 0.1 M PBS under the 7 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

potential of −0.2 V, followed by injecting 0.1 mM H2O2, 1 mM UA, 1 mM L-Cys, 1 mM AA and 1 mM glucose solution. As presented in Figure 6a, except the remarkable current response for the H2O2, there were no distinctive current changes after the injection of the above interferences. These results suggest the PtPb/G/GCE holds high selectivity for the electrochemical detection of H2O2. The possibility of practical application of PtPb/G/GCE sensor was checked by performing real-time detection of H2O2 in the cells. The Raw 264.7 cell was selected as the model for the real-time detection of H2O2 by adding the Nformylmethionyl-leucyl-phenylalanine (fMLP) as the stimulant. The cells were grown at 37 oC in 5% CO2 in 75 cm2 flasks and collected by centrifugation. When growing to 90% confluence, the number of cells was estimated by a hemcytometer to be 3×106 after washing with PBS (7.4) three times. The final packed cells were re-dispersed in 30 mL PBS (pH = 7.4) for the electrochemical experiments. As shown in Figure 6b, with the addition of 0.3 μM fMLP into PBS containing Raw 264.7 cells, the recorded current changed by about 1.1 μA, corresponding to 10 nM H2O2 generating from cells. In contrast, no apparent current changes can be observed in the presence of only fMLP or only cells, confirming the detective H2O2 was produced from the Raw 264.7 cells.

CONCLUSIONS In summary, we report a self-assembly method for making a novel 2D PtPb/G composite nanomaterial as enhanced sensing platform for high-sensitivity nonenzymatic H2O2 sensor by firstly synthesizing intermetallic PtPb hexagonal nanoplates via a wet-chemistry approach, and subsequently assembling them onto graphene. Compare to commercial Pt/C, the PtPb/G displayed much enhanced electrocatalytic activity and fast response toward reduction of H2O2 due to the supermassive specific surface area of 2D PtPb nanoplates, ultra-high conductivity of G and synergistic effect between them. The as-made biosensor using the PtPb/G has extremely high sensitivity and good selectivity in neutral solution. The detection limit can reach 2 nM, which can successfully achieve the real-time detect H2O2 released from Raw 246.7 cells. This study highlights the role of compositional and morphological tuning of metallic nanomaterials in developing high-sensitivity non-enzymatic biosensors.

AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected].

8 / 19


Page 8 of 19

Page 9 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Notes The authors declare no competing financial interest.

ACKNOWLEDGMENTS This work was financially supported by the National Natural Science Foundation of China (51671003, 21571112 and 51372125), the National Key Research and Development Program of China (No. 2016YFB0100201), the start-up supports from Peking University and Young Thousand Talented Program.

REFERENCE

(1) Ferri, T.; Poscia, A.; Santucci, R. Bioelectrochem. Bioenerg. 1998, 45, 221-226. (2) Miller, E. W.; Albers, A. E.; Pralle, A.; Isacoff, E. Y.; Chang, C. J. J. Am. Chem. Soc. 2005, 127, 16652-16659. (3) Lambeth, J. D. Nat. Rev. Immunol. 2004, 4, 181-189. (4) Sun, X.; Guo, S.; Liu, Y.; Sun, S. Nano Lett. 2012, 12, 4859-4863. (5) Li, Z.; Xin, Y.; Wu, W.; Fu, B.; Zhang, Z. Anal. Chem. 2016, 88, 7724-7729. (6) Albers, A. E.; Okreglak, V. S.; Chang, C. J. J. Am. Chem. Soc. 2006, 128, 9640-9641. (7) Chen, S.; Hai, X.; Chen, X.-W.; Wang, J.-H. Anal. Chem. 2014, 86, 6689-6694. (8) Kikuchi, K.; Nagano, T.; Hayakawa, H.; Hirata, Y.; Hirobe, M. Journal of Biological Chemistry 1993, 268, 23106-23110. (9) Elzanowska, H.; Abu-Irhayem, E.; Skrzynecka, B.; Birss, V. I. Electroanalysis 2004, 16, 478-490. (10) Bai, J.; Jiang, X. Anal. Chem. 2013, 85, 8095-8101. (11) Wang, T.; Zhu, H.; Zhuo, J.; Zhu, Z.; Papakonstantinou, P.; Lubarsky, G.; Lin, J.; Li, M. Anal. Chem. 2013, 85, 10289-10295. (12) Zhou, J.; Liao, C.; Zhang, L.; Wang, Q.; Tian, Y. Anal. Chem. 2014, 86, 4395-4401. (13) Thiagarajan, S.; Tsai, T. H.; Chen, S.-M. Int. J. Electrochem. Sci. 2011, 6, 2235-2245. 9 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(14) Dong, C.; Zhong, H.; Kou, T.; Frenzel, J.; Eggeler, G.; Zhang, Z. ACS Appl. Mater. Interfaces. 2015, 7, 2021520223. (15) Jv, Y.; Li, B.; Cao, R. Chem. Commun. 2010, 46, 8017-8019. (16) Kong, L.; Ren, Z.; Zheng, N.; Du, S.; Wu, J.; Tang, J.; Fu, H. Nano Res. 2015, 8, 469-480. (17) Guo, C.; Hu, F.; Li, C. M.; Shen, P. K. Biosens. Bioelectron. 2008, 24, 819-824. (18) Evans, S. A. G.; Elliott, J. M.; Andrews, L. M.; Bartlett, P. N.; Doyle, P. J.; Denuault, G. Anal. Chem. 2002, 74, 1322-1326. (19) Yuan, Z.; Janyasupab, M.; Chen-Wei, L.; Po-Yuan, L.; Kuan-Wen, W.; Jiaqiang, X.; Chung-Chiun, L. Int. J. Electrochem. Sci. 2012, 410846-410846. (20) Zhang, Y.; Bai, X.; Wang, X.; Shiu, K.-K.; Zhu, Y.; Jiang, H. Anal. Chem. 2014, 86, 9459-9465. (21) Wen, Z.; Ci, S.; Li, J. J. Phys. Chem. C 2009, 113, 13482-13487. (22) Lu, D.; Zhang, Y.; Lin, S.; Wang, L.; Wang, C. Talanta 2013, 112, 111-116. (23) Niu, X. H.; Shi, L. B.; Zhao, H. L.; Lan, M. B. Analytical Methods 2016, 8, 1755-1764. (24) Stephens, I. E. L.; Bondarenko, A. S.; Gronbjerg, U.; Rossmeisl, J.; Chorkendorff, I. Energy Environ. Sci. 2012, 5, 6744-6762. (25) Bu, L.; Zhang, N.; Guo, S.; Zhang, X.; Li, J.; Yao, J.; Wu, T.; Lu, G.; Ma, J.-Y.; Su, D.; Huang, X. Science. 2016. 354, 1410-1414. (26) Huang, K.-J.; Niu, D.-J.; Liu, X.; Wu, Z.-W.; Fan, Y.; Chang, Y.-F.; Wu, Y.-Y. Electrochim. Acta 2011, 56, 2947-2953. (27) Guo, S.; Sun, S. J. Am. Chem. Soc. 2012, 134, 2492-2495. (28) Guo, S.; Dong, S. Chem. Soc. Rev. 2011, 40, 2644-2672. (29) Guo, S.; Wen, D.; Zhai, Y.; Dong, S.; Wang, E. ACS Nano 2010, 4, 3959-3968. 10 / 19


Page 10 of 19

Page 11 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(30) Saleem, F.; Zhang, Z.; Xu, B.; Xu, X.; He, P.; Wang, X. J. Am. Chem. Soc. 2013, 135, 18304-18307. (31) Huang, X.; Tang, S.; Mu, X.; Dai, Y.; Chen, G.; Zhou, Z.; Ruan, F.; Yang, Z.; Zheng, N. Nature Nanotech. 2011, 6, 28-32. (32) Zhao, Y.; Feng, J.; Liu, X.; Wang, F.; Wang, L.; Shi, C.; Huang, L.; Feng, X.; Chen, X.; Xu, L.; Yan, M.; Zhang, Q.; Bai, X.; Wu, H.; Mai, L. Nat. Commun. 2014, 5. (33) Guo, S.; Zhang, S.; Wu, L.; Sun, S. Angew. Chem. Int. Ed. 2012, 51, 11770-11773. (34) Yang, M.; Yang, Y.; Liu, Y.; Shen, G.; Yu, R. Biosens. Bioelectron. 2006, 21, 1125-1131 (35) Lu, W.; Chang, G.; Luo, Y.; Liao, F.; Sun, X. J. Mater. Sci. 2011, 46, 5260-5266. (36) Wang, N.; Han, Y.; Xu, Y.; Gao, C.; Cao, X. Anal. Chem. 2015, 87, 457-463. (37) Fugang, X.; Yujing, S.; Yue, Z.; Yan, S.; Zhiwei, W.; Zhuang, L. Electrochem. Commun. 2011, 13, 1131-4.

11 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 1. TEM (a, b) and high-resolution TEM (c) images of PtPb nanoplates. (d) TEM of PtPb/G composites.

12 / 19


Page 12 of 19

Page 13 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 2. (a) CVs of potassium ferricyanide solution containing 0.1 M KCl and 5 mM K3[Fe(CN)6] on the bare GCE, G/GCE and PtPb/G/GCE. Scan rate: 100 mV/s. (b) CVs of G, Pt/C and PtPb/G electrodes in N2-saturated 0.1 M PBS (7.4) solution containing 10 mM H2O2 at a scan rate of 100 mVs−1.

13 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 3. (a) CVs of PtPb/G/GCE in N2-saturated 0.1 M PBS (pH 7.4) in the absence and presence of H2O2 with different concentrations (0, 0.1, 0.2, 0.5, 0.8, 1, 1.5, 2, 2.5, 3 mM). Scan rate, 100 mV/s. (b) Calibration curve of the amperometric response to the concentration of H2O2 from 0 mM to 3 mM. (c) CVs of G-PtPb/GCE in N2-saturated 0.1 M PBS (pH 7.4) containing 0.5 mM H2O2 at different scan rates (20, 50, 80, 100, 150, 200, 250, 300, 400, 500 mV/s). (d) Plot of electrocatalytic current of H2O2 at 0.1 V versus v1/2.

14 / 19


Page 14 of 19

Page 15 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 4. (a) Amperometric response of PtPb/G electrode at various potentials (vs Ag/AgCl) in 0.1 M PBS (7.4) solution with the successive addition of 0.2 mM H2O2. (b) Calibration curves of the PtPb/G electrode at various potentials with the successive addition of 0.2 mM H2O2 in 0.1 M PBS (7.4) solution. (c) Amperometric response of different electrode (G, Pt/C, PtPb/G) at −0.2V (vs Ag/AgCl) in 0.1 M PBS (7.4) solution with the successive addition of 0.2 mM H2O2. (d) Calibration curves of the different electrode at −0.2V with the successive addition of 0.2mM H2O2 in 0.1 M PBS (7.4) solution.

15 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 5. (a) Amperometric responses of the PtPb/G nanoplate modified GC electrode to the successive addition of H2O2 in PBS at an applied potential of −0.2 V. The inset shows a close look of blue oval region with the H2O2 concentration from 0.14 to 6.34 μM. (b) A close look of red circle with the H2O2 concentration from 2 to 6 nM. (c) The dependence of the response of the electrode on H2O2 concentration. (d) The concentration of H2O2 from 0.002 0.236 μM. (e) The concentration of H2O2 from 0.236 -11.34 μM. (f) The concentration of H2O2 from 11.34 - 2516 μM.

16 / 19


Page 16 of 19

Page 17 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 6. (a) Chronoamperometric curves of the PtPb/G electrode in a 0.1 M phosphate buffer (pH 7.4) with the successive addition of 0.1mM H2O2 ,1 mM UA, 1 mM L-Cys, 1 mM AA, 1mM GLU and 0.1 mM H2O2 with a constant potential at −0.2V. (b) Amperometric responses of the PtPb/G electrode to the addition of 0.3 μM fMLP with and without Raw 264.7 cells as well as in the presence of Raw 264.7 cells without fMLP in the N2 saturated PBS at−0.2 V vs. Ag/AgCl.

17 / 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 19

Table 1. Comparison of the performance of different electrode materials for H2O2 detection electrode materials

detection limit (μM)

detection potential (V)

Linear range (μM)

ref

Ag/graphene oxide

1.9

−0.3 (vs Ag/AgCl)

100-20000

35

graphene/Pt-nanocomposite

0.2

−0.08 (vs Ag/AgCl)

0.5-3475

20

Au67Cu33 nanowire

0.002

0.484 (vs SCE)

0.003-440

36

PtPd-Fe3O4/C

0.005

−0.25 (vs Ag/AgCl)

0.02-67

4

graphene/Pt-nanocomposits

0.5

0 (vs Ag/AgCl)

2-710

37

Pt/carbon nanotube

1.5

−0.1 (vs Ag/AgCl)

5-25000

21

PtAu/graphene-muliwalled carbon nanotubes

0.6

0.6 (vs SCE)

20-40000

22

PtPb/G

0.002

−0.2 (vs Ag/AgCl)

0.002-2516

this work

18 / 19


Page 19 of 19

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


TOC

19 / 19


Intermetallic PtPb Nanoplates Composites for Boosting

Recommend Documents