Enhanced Sensitivity for Electrochemical Detection Using Screen

Subscriber access provided by Flinders University Library

Article

Enhanced Sensitivity for Electrochemical Detection Using ScreenPrinted Diamond Electrodes via the Random Microelectrode Array Effect Takeshi Kondo, Ikuto Udagawa, Tatsuo Aikawa, Hironori Sakamoto, Isao Shitanda, Yoshinao Hoshi, Masayuki Itagaki, and Makoto Yuasa Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.5b03986 • Publication Date (Web): 10 Jan 2016 Downloaded from http://pubs.acs.org on January 17, 2016

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 8

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

Enhanced Sensitivity for Electrochemical Detection Using ScreenPrinted Diamond Electrodes via the Random Microelectrode Array Effect Takeshi Kondo,*,†,‡,§ Ikuto Udagawa,† Tatsuo Aikawa,† Hironori Sakamoto,† Isao Shitanda,†,‡ Yoshinao Hoshi,† Masayuki Itagaki†,‡ and Makoto Yuasa†,‡,§ †

Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan ‡ Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan § ACT-C/JST, 4-1-8 Honcho, Kawaguchi, Saitama 333-0012, Japan ABSTRACT: The electrochemical properties of screen-printed diamond electrodes with various insulating polyester (PES) resin binder/boron-doped diamond powder (BDDP) ratios were investigated for high sensitivity electrochemical detection. For PES/BDDP weight ratios in the range of 0.3 – 0.5, the BDDP-printed electrodes exhibited cyclic voltammetry (CV) characteristics for Fe(CN)63−/4− that are typical of a planar electrode, while microelectrode-like characteristics with sigmoidal CV curves were observed for PES/BDDP ratios of 1.0 – 2.0. Cu elemental mapping images of copper-electrodeposited BDDP-printed electrodes indicated the formation of island structures with conductive BDDP domains surrounded by an insulating PES matrix for large PES/BDDP ratios. The electrochemical detection of ascorbic acid (AA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) was also investigated using polycrystalline BDD thin-film and BDDP-printed electrodes (PES/BDDP ratio = 0.3 and 1.0). As a result, the signal-to-background (S/B) ratios for the voltammetric detection of AA and 8-OHdG were in the order BDDP-printed electrode (PES/BDDP = 1.0) > BDDP-printed electrode (PES/BDDP = 0.3) > polycrystalline BDD thin film electrode, based on the large faradaic current with respect to the background current. Therefore, the BDDP-printed electrode with a large insulating binder/BDDP ratio has the potential for use as a disposable electrode for electrochemical detection. The electrode is cheaper, lighter, and more sensitive than conventional BDD electrodes.

Boron-doped diamond (BDD) electrodes are expected to be used for high sensitivity electrochemical detection based on their unique electrochemical properties, which include a wide potential window and low background current.1 BDD thin films are typically deposited on a limited number of substrate material types, such as silicon wafers and niobium plates, which results in high production costs and poor processability of the BDD electrodes. Thus, we have developed a screenprinted diamond electrochemical electrode to achieve lowcost, light-weight, disposability and high sensitivity.2,3 An ink containing BDD powder (BDDP) and an insulating polyester (PES) resin binder was screen-printed on a polyimide substrate to fabricate the BDDP-printed electrode. The BDDP-printed electrode had a lower background current than a conventional carbon-printed electrode, which resulted in a larger signal-tobackground (S/B) ratio.2 A cobalt phthalocyanin (CoPc)modified BDDP-printed electrode prepared with a BDDP ink containing CoPc can be used for the electrochemical detection of hydrogen peroxide (H2O2) based on the electrocatalytic effect of CoPc. A glucose sensor was also fabricated by depositing a glucose oxidase-immobilized film on the CoPc/BDDPprinted electrode surface.3 The microelectrode method is an effective approach to enhancing the S/B ratio for electrochemical detection based on a large faradaic current by efficient mass transport with respect to a small capacitive background current. Microelectrodes also

have some advantages in electrochemical analysis, such as a steady-state response current and small IR drop, which enables electrochemical measurements in a solution with high resistivity, and they can be used for electroanalysis with small sample volumes or at microscopic locations. There have been many reports on diamond-based microelectrodes.4-9 For example, Fierro et al. fabricated a needle-type diamond microelectrode by deposition of a BDD film on the tip of a tungsten wire, and demonstrated the high sensitivity electrochemical detection of dopamine6 and glutathione7 in the living body. Microelectrode arrays can provide an enhanced current density when a diffusion layer of each microelectrode in the array is isolated from each other without overlap. The fabrication of diamond-based microelectrode arrays using different techniques has also been reported, such as micromachining10,11 and photolithograpy techniques.12-14 Fabrication of microelectrodes or microelectrode arrays often requires proficient skills and/or complicated techniques such as photolithograpy. In contrast, random microelectrode arrays (or microelectrode ensembles) can be fabricated with simple procedures. One typical way to fabricate random microelectrode arrays is to partially cover a macro-electrode, such as gold,15,16 carbon,17,18 copper,19 and BDD20 with an insulating mask. Another is to use composites of micrometersized particle/disks of conducting materials with an insulating matrix.21-25 For example, Ilinoiu et al. reported the fabrication

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

of a quasi-microelectrode with a zeolite-modified graphiteepoxy composite,26 where conducting graphite particles are dispersed in an insulating epoxy resin matrix to form a random microelectrode array structure on the electrode surface. In this study, the electrochemical properties of BDDPprinted electrodes with a large PES/BDDP ratio was investigated for highly sensitive electrochemical detection based on the random microelectrode array effect. To fabricate a typical planar electrode, the PES/BDDP ratio should be as small as possible, and a ratio of 0.3 is optimal with good printing reproducibility, as reported in our previous study.2 However, when the PES/BDDP ratio is significantly large, exposed conductive BDDP should be dispersed in the insulating matrix (PES) on the electrode surface to achieve microelectrode array-like electrochemical behavior. A microelectrode array generally exhibits a larger diffusion-controlled faradaic current with respect to the background (double-layer) current by the hemispherical diffusion mode than that for a planar electrode with a linear diffusion mode. In the present study, BDDPprinted electrodes were prepared using a BDDP ink with a PES/BDDP ratio of 0.3 – 2.0 and the electrochemical properties were investigated toward the fabrication of a random microelectrode array-type electrode. The electrochemical detection of ascorbic acid (AA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) by the BDDP-printed electrode was then compared with a conventional BDD thin film electrode.

Page 2 of 8

scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS, JSM-7600F, JEOL).

Resist BDDP Resist Silver paste Carbon

Polyimide film

Figure 1. Schematic illustration of the procedure for fabrication of the BDDP-printed electrode.

EXPERIMENTAL SECTION BDDP was prepared by microwave plasma-assisted chemical vapor deposition of BDD on the surface of diamond powder (DP; Micron+SND, diameter BDDP-printed electrode (PES/BDDP = 0.3) > polycrystalline BDD electrode

600

BG 0

50 40 30 y = 141.9 x - 1.9

20 10 0

50

100

150

200

250

0

Time / s

0.1

140

14 12

120

10 8

100

6 4

80

40 20 0 -20 -50

2

500 μM 400 200 100

60

0 0

200

400

600

AA concentration / μM

BG 0

100

150

200

c 8

2

500 μM 400 200 100

1.5 1 0.5 0 0

200

400

600

AA concentration / μM 2

30 y = 116.49x + 2.7

20 10

0

0.1

0.2

0.3

0.4

t−1/2 / s−1/2 5 4 3

y = 4.4 x + 2.5

2 1 0

BG 0

40

f

3 2.5

-50

0.4

50

250

Time / s

4

0.3

0 50

6

0.2

t−1/2 / s−1/2

e

b

50

100

Time / s

0.731

400

AA concentration / μM

20

0

3.739

0

Current density / μA cm−2

20


0.0

40


-0.5

60


40

500 μM 400 200 100

80


60

100

(Table 2). Similar to the CV results, the faradaic currents at the polycrystalline BDD and BDDP-printed (PES/BDDP = 0.3) electrodes were comparable and the background current was smaller at the BDDP-printed electrode (PES/BDDP = 0.3) than at the polycrystalline BDD electrode, which resulted in a larger S/B ratio at the BDDP-printed electrode. The largest S/B ratio among the three electrodes was observed for the BDDP-printed electrode (PES/BDDP = 1.0), which is considered to be based on the random microelectrode array effect. This is also supported by the Cottrel (i vs. t−1/2) plot shown in Fig. 7d–7f. According to the Cottrell equation, the diffusioncontrolled faradaic current for the linear diffusion mode (planar electrode) il is directly proportional to t−1/2, where t is time after the potential step. However, for the hemispherical diffusion mode (microelectrode), the faradaic current ih is expressed by ih = il + iconst, where iconst is a time-independent term.29 For the polycrystalline BDD and BDDP-printed (PES/BDDP = 0.3) electrodes, the approximate straight line of the Cottrel plot passed through the origin practically (Fig. 7d and 7e), indicating the linear diffusion mode. In the case of the BDDP-printed electrode (PES/BDDP = 1.0), however, the intercept of the approximate line was significantly large (2.5 µA cm−2) with respect to the slope (4.4 µA cm−2 µM−1), implying the hemispherical diffusion mode or an intermediate state between the linear and hemispherical diffusion modes.


80



120


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


150

200

250

0

0.1

0.2

0.3

0.4

t−1/2 / s−1/2

Figure 7. CA for 0.1 M Na2SO4 containing various concentrations of AA using (a) the polycrystalline BDD thin film electrode, and BDDP-printed electrodes with PES/BDDP ratios of (b) 0.3 and (c) 1.0. The electrode potential was +0.8 V vs. Ag/AgCl. Insets show plots of anodic current density (200 s after potential step) vs. AA concentration. (d–f) Cottrel (i vs. t−1/2) plots created from the CA data (a–c), respectively.

Differential pulse voltammetry for 8-OHdG. Differential pulse voltammetry (DPV) for 8-OHdG detection was performed to demonstrate an electroanalytical application of the BDDP-printed electrode. 8-OHdG is known to be the most


Analytical Chemistry abundant product generated by oxidative DNA damage,30,31 and high sensitivity electroanalysis of this oxidative stress marker, e.g., from urine, is desirable for biomedical applications.32-35 DPV measurements with the polycrystalline BDD and BDDP-printed (PES/BDDP = 0.3) electrodes showed single anodic peaks and the peak current densities were linear with respect to the 8-OHdG concentration (3 – 35 µM) (Figs. 8a and 8b). In contrast, sigmoidal DPV curves were observed for the BDDP-printed electrode (PES/BDDP = 1.0), which indicates the microelectrode array effect (Fig. 8c). The S/B ratio was also larger for this electrode in the order of BDDPprinted electrode (PES/BDDP = 1.0) > BDDP-printed electrode (PES/BDDP = 0.3) > polycrystalline BDD electrode, which is consistent with the CV and CA results for AA. The results indicate that BDDP-printed electrodes with a large PES/BDDP ratio (e.g., 1.0) would be useful for high sensitivity electrochemical detection of AA and other electroative analytes with different techniques (CV, CA and DPV), due to a larger S/B ratio than that obtained for conventional polycrystalline BDD electrodes, which is known to be a functional electrode material for electroanalysis. 10

15

10

35 μM 17 7 3

5

0 0.0



20

BG

0.2

0.4

0.6

0.8

8

2

AUTHOR INFORMATION

BG

0.2

0.4

0.6

0.8

1.0

Potential / V vs. Ag/AgCl

0.6

6

0.5

5

0.3

S/B ratio

35 μM 17 7 3

0.2

BDDP-printed (PES/BDDP = 1.0)

4

ACKNOWLEDGMENT

BDDP-printed (PES/BDDP = 0.3)

3 2

This work was supported in part by KAKENHI (Nos. 24750208 and 26410246) grants from the Japan Society for the Promotion of Science (JSPS).

1

0.1

Polycrystalline BDD

BG

0.0 0.0

Corresponding Author *E-mail: [email protected].

d

0.4

Supporting Information

4


c

ASSOCIATED CONTENT

CVs for ferricyanide at BDDP-printed electrode (PES/BDDP = 2.0) at various potential sweep rate (PDF)

35 μM 17 7 3

6

0 0.0

1.0

ered to be responsible for the microelectrode behavior. The S/B ratios for CV and CA measurements of AA were larger and in the order of BDDP-printed electrode (PES/BDDP = 1.0) > BDDP-printed electrode (PES/BDDP = 0.3) > polycrystalline BDD electrode. This trend can be explained by a combination of the faradaic current based on the diffusion mode (linear or hemispherical) and the background current, which is directly proportional to the total conductive surface area. Highly sensitive electroanalysis of 8-OHdG with DPV at the BDDP-printed electrode was also demonstrated, and the behavior was consistent with the results of CV and CA for ferri/ferrocyanide and AA. Therefore, the BDDP-printed electrode with a larger binder/BDDP ratio has potential as a cheaper, more light-weigh and sensitive disposable electrode with respect to the conventional polycrystalline BDD electrode.

The Supporting Information is available free of charge on the ACS Publications website.

b

a


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 6 of 8

0.2

0.4

0.6

0.8


0

1.0

0

10

20

30

40

8-OHdG concentration / μM

Figure 8. DPV for 0.1 M Na2SO4 containing various concentrations of 8-OHdG using (a) the polycrystalline BDD thin film electrode, and BDDP-printed electrodes with PES/BDDP ratios of (b) 0.3 and (c) 1.0. The potential sweep rate, pulse height and pulse width were 100 mV s−1, 50 mV and 100 ms, respectively. (d) S/B ratio for 8-OHdG detection as a function of the 8-OHdG concentration.

CONCLUSIONS The effect of the PES (binder)/BDDP ratio on the electrochemical properties of BDDP-printed electrodes was investigated. At PES/BDDP ratios in the range of 0.3 – 0.5, the BDDP-printed electrode exhibited CV characteristics typical of a planar electrode with the linear diffusion mode at moderate potential sweep rates (e.g. 100 mV s−1), which is considered to be due to the dense packing of BDDP on the electrode surface. On the other hand, the diffusion mode was found to transition from linear to hemispherical at PES/BDDP ratios in the range of 1.0 – 2.0. EDS mapping of copper-deposited BDDP-printed electrode surfaces revealed the formation of island structures of conductive domains with size of several micrometers to several tens of micrometers, which are consid-

REFERENCES (1) Diamond Electrochemistry; Elsevier-BKC: Tokyo, 2005. (2) Kondo, T.; Sakamoto, H.; Kato, T.; Horitani, M.; Shitanda, I.; Itagaki, M.; Yuasa, M. Electrochem. Commun. 2011, 13, 1546-1549. (3) Kondo, T.; Horitani, M.; Sakamoto, H.; Shitanda, I.; Hoshi, Y.; Itagaki, M.; Yuasa, M. Chem. Lett. 2013, 42, 352-354. (4) Sarada, B. V.; Rao, T. N.; Tryk, D. A.; Fujishima, A. J. Electrochem. Soc. 1999, 146, 1469-1471. (5) Cvačka, J.; Quaiserová, V.; Park, J.; Show, Y.; Muck, A.; Swain, G. M. Anal. Chem. 2003, 75, 2678-2687. (6) Suzuki, A.; Ivandini, T. A.; Yoshimi, K.; Fujishima, A.; Oyama, G.; Nakazato, T.; Hattori, N.; Kitazawa, S.; Einaga, Y. Anal. Chem. 2007, 79, 8608-8615. (7) Fierro, S.; Yoshikawa, M.; Nagano, O.; Yoshimi, K.; Saya, H.; Einaga, Y. Sci. Rep. 2012, 2, 901. (8) Silva, E.; Bastos, A. C.; Neto, M.; Fernandes, A. J.; Silva, R.; Ferreira, M. G. S.; Zheludkevich, M.; Oliveira, F. Sens. Actuat. B 2014, 204, 544551. (9) Silva, E. L.; Gouvêa, C. P.; Quevedo, M. C.; Neto, M. A.; Archanjo, B. S.; Fernandes, A. J. S.; Achete, C. A.; Silva, R. F.; Zheludkevich, M. L.; Oliveira, F. J. Anal. Chem. 2015, 87, 6487-6492. (10) Pagels, M.; Hall, C. E.; Lawrence, N. S.; Meredith, A.; Jones, T. G. J.; Godfried, H. P.; Pickles, C. S. J.; Wilman, J.; Banks, C. E.; Compton, R. G.; Jiang, L. Anal. Chem. 2005, 77, 3705-3708. (11) Simm, A. O.; Banks, C. E.; Ward-Jones, S.; Davies, T. J.; Lawrence, N. S.; Jones, T. G. J.; Jiang, L.; Compton, R. G. Analyst 2005, 130, 13031311. (12) Smirnov, W.; Yang, N.; Hoffmann, R.; Hees, J.; Obloh, H.; MüllerSebert, W.; Nebel, C. E. Anal. Chem. 2011, 83, 7438-7443.


Page 7 of 8

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


(13) Yang, N.; Smirnov, W.; Hees, J.; Hoffmann, R.; Kriele, A.; Obloh, H.; Müller-Sebert, W.; Nebel, C. E. Phys. Stat. Sol. (a) 2011, 208, 2087-2092. (14) Kiran, R.; Rousseau, L.; Lissorgues, G.; Scorsone, E.; Bongrain, A.; Yvert, B.; Picaud, S.; Mailley, P.; Bergonzo, P. Sensors 2012, 12, 76697681. (15) Macech, P.; Pemberton, J. E. Thin Solid Films 2009, 517, 5399-5403. (16) Valencia, D. P.; de Souza, A. P. R.; Gonçales, V. R.; Antonio, J. L. S.; Cordoba de Torresi, S. I.; Bertotti, M. Electrochem. Commun. 2014, 38, 32-35. (17) Choudhry, N. A.; Kadara, R. O.; Banks, C. E. Phys. Chem. Chem. Phys. 2010, 12, 2285-2287. (18) Choudhry, N. A.; Khairy, M.; Kadara, R. O.; Jenkinson, N.; Banks, C. E. Electroanalysis 2010, 22, 1831-1836. (19) de Souza, A. P. R.; Felix, F. S.; Dantas, L. M. F.; Angnes, L.; Bertotti, M. Sens. Actuat. B 2014, 203, 406-411. (20) Xiao, L.; Streeter, I.; Wildgoose, G. G.; Compton, R. G. Sens. Actuat. B 2008, 133, 118-127. (21) Fletcher, S.; Horne, M. D. Electrochem. Commun. 1999, 1, 502-512. (22) Lacroix, M.; Bianco, P.; Lojou, E. Electroanalysis 1999, 11, 10681076. (23) Ramirez-Garcia, S.; Alegret, S.; Cespedes, F.; Forster, R. J. Analyst 2002, 127, 1512-1519. (24) Cięciwa, A.; Wüthrich, R.; Comninellis, C. Electrochem. Commun. 2006, 8, 375-382. (25) Ghamouss, F.; Tessier, P. Y.; Djouadi, M. A.; Besland, M. P.; Boujtita, M. Electrochem. Commun. 2007, 9, 1798-1804. (26) Ilinoiu, E.; Manea, F.; Serra, P.; Pode, R. Sensors 2013, 13, 7296. (27) Guo, J.; Lindner, E. Anal. Chem. 2008, 81, 130-138. (28) Hees, J.; Hoffmann, R.; Kriele, A.; Smirnov, W.; Obloh, H.; Glorer, K.; Raynor, B.; Driad, R.; Yang, N.; Williams, O. A.; Nebel, C. E. ACS Nano 2011, 5, 3339-3346. (29) Bard, A. J.; Faukner, L. R. In Electrochemical Methods: Fundamentals and Applications; John Wiley & Sons, 2000, pp 161-168. (30) Loft, S.; Vistisen, K.; Ewertz, M.; Tjønneland, A.; Overvad, K.; Poulsen, H. E. Cardnogeoesis 1992, 13, 2241-2247. (31) Halliwell, B. Biochem. J. 2007, 401, 1-11. (32) Gutiérrez, A.; Gutiérrez, S.; García, G.; Galicia, L.; Rivas, G. A. Electroanalysis 2011, 23, 1221-1228. (33) Kato, D.; Komoriya, M.; Nakamoto, K.; Kurita, R.; Hirono, S.; Niwa, O. Anal. Sci. 2011, 27, 703-707. (34) Yao, Q.-H.; Mei, S.-R.; Weng, Q.-F.; Zhang, P.-d.; Yang, Q.; Wu, C.y.; Xu, G.-W. Talanta 2004, 63, 617-623. (35) Wu, L. L.; Chiou, C.-C.; Chang, P.-Y.; Wu, J. T. Clin. Chim. Acta 2004, 339, 1-9.



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 8 of 8

Authors are required to submit a graphic entry for the Table of Contents (TOC) that, in conjunction with the manuscript title, should give the reader a representative idea of one of the following: A key structure, reaction, equation, concept, or theorem, etc., that is discussed in the manuscript. Consult the journal’s Instructions for Authors for TOC graphic specifications.


8

Enhanced Sensitivity for Electrochemical Detection Using Screen

Recommend Documents