Anal. Chem. 2009, 81, 7271–7280
Nonenzymatic Electrochemical Detection of Glucose Based on Palladium-Single-Walled Carbon Nanotube Hybrid Nanostructures Ling Meng, Juan Jin, Gaixiu Yang, Tianhong Lu, Hui Zhang,* and Chenxin Cai* Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, P. R. China A new electrocatalyst, palladium nanoparticle-singlewalled carbon nanotube (Pd-SWNTs) hybrid nanostructure, for the nonenzymatic oxidation of glucose was developed and characterized by X-ray diffraction (XRD) and the transmission electron microscope (TEM). The hybrid nanostructures were prepared by depositing palladium nanoparticles with average diameters of 4-5 nm on the surface of single-walled carbon nanotubes (SWNTs) via chemical reduction of the precursor (Pd2+). The electrocatalyst showed good electrocatalytic activity toward the oxidation of glucose in the neutral phosphate buffer solution (PBS, pH 7.4) even in the presence of a high concentration of chloride ions. A nonenzymatic amperometric glucose sensor was developed with the use of the Pd-SWNT nanostructure as an electrocatalyst. The sensor had good electrocatalytic activity toward oxidation of glucose and exhibited a rapid response (ca.3 s), a low detection limit (0.2 ( 0.05 µM), a wide and useful linear range (0.5-17 mM), and high sensitivity (∼160 µA mM-1 cm-2) as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, uric acid, 4-acetamidophenol, 3,4-dihydroxyphenylacetic acid, and so forth did not cause any interference due to the use of a low detection potential (-0.35 V vs SCE). The sensor can also be used for quantification of the concentration of glucose in real clinical samples. Therefore, this work has demonstrated a simple and effective sensing platform for nonenzymatic detection of glucose. Glucose detection is of great interest from several points of view ranging from medical applications of blood glucose sensing to ecological approaches, such as in wastewater treatment, in food and textile industries, in environmental monitoring,1-4 and so forth. Much effort has been focused on developing suitable techniques for precisely monitoring the glucose level with high sensitivity, high reliability, fast response, good selectivity, and low * Corresponding author. E-mail:
[email protected] (H.Z.); cxcai@ njnu.edu.cn (C.C.). (1) Lee, S.-R.; Lee, Y. -T.; Sawada, K.; Takao, H.; Ishida, M. Biosens. Bioelectron. 2008, 24, 410–414. (2) Newman, J. D.; Turner, A. P. F. Biosens. Bioelectron. 2005, 20, 2435–2453. (3) Wu, L.; Zhang, X.; Ju, H. Biosens. Bioelectron. 2007, 19, 141–147. (4) Shoji, E.; Freund, M. S. J. Am. Chem. Soc. 2001, 123, 3383–3384. 10.1021/ac901005p CCC: $40.75 2009 American Chemical Society Published on Web 08/10/2009
cost. There are now many approaches to measure glucose concentration, such as the optical techniques including infrared spectroscopy, Raman spectroscopy, and photo acoustic spectroscopy,5-8 surface plasmon resonance biosensor,9 capacitive detection,10 electrochemiluminescene,11 colorimetry,12 the electrochemical method,1,4,13-17 and so forth. Among these techniques, the electrochemical approach has attracted significant attention and has become a promising method for its simplicity, high reliability, sensitivity and selectivity, low detection limit, low cost, compatibility for miniaturization, and ease of use. Electrochemical detection of glucose is usually based on glucose dehydrogenase (GDH)18 or glucose oxidase (GOx).13,16,17,19-22 The GDH-based biosensors involve the electrochemistry of NADH (reduced form of β-nicotinamide adenine dinucleotide). Therefore, this kind of biosensor requires the addition of a soluble NAD+ cofactor, which complicates the analysis system. Moreover, the electrochemical oxidation of NADH is not straightforward and requires high overpotential (usually 0.7 to 1.0 V) owing to its sluggish electron transfer kinetics.23-28 The GOx-based glucose (5) Song, C.; Pehrsson, P. E.; Zhao, W. J. Mater. Res. 2006, 21, 2817–2823. (6) Barone, P. W.; Parker, R. S.; Strano, M. S. Anal. Chem. 2005, 77, 7556– 7562. (7) Waynant, R. W.; Chenault, V. M. LEOS Newsletter 1998, 3, 3–6. (8) Spanner, G.; Niessner, R. Fresenius J. Anal. Chem. 1996, 354, 306–310. (9) Shen, X. W.; Huang, C. Z.; Li, Y. F. Talanta 2007, 72, 1432–1437. (10) Cheng, Z.; Wang, E.; Yang, X. Biosens. Bioelectron. 2001, 16, 179–185. (11) Kremeskotter, J.; Wilson, R.; Schiffrin, D. J.; Luff, B. J.; Wilkinson, J. S. Meas. Sci. Technol. 1995, 6, 1325–1328. (12) Morikawa, M.; Kimizuka, N.; Yoshihara, M.; Endo, T. Chem.sEur. J. 2002, 8, 5580–5584. (13) Du, P.; Zhou, B.; Cai, C. X. J. Electroanal. Chem. 2008, 614, 149–156. (14) Kandimalla, V. B.; Tripathi, V. S.; Ju, H. Biomaterials 2006, 27, 1167– 1174. (15) Xian, Y.; Hu, Y.; Liu, F.; Xian, Y.; Feng, L.; Jin, L. Biosens. Bioelectron. 2007, 22, 2827–2833. (16) Wang, Z.; Liu, S.; Wu, P.; Cai, C. X. Anal. Chem. 2009, 81, 1638–1645. (17) Zhao, M.; Wu, X.; Cai, C. X. J. Phys. Chem. C 2009, 113, 4987–4996. (18) Du, P.; Wu, P.; Cai, C. X. J. Electroanal. Chem. 2008, 624, 21–26. (19) Jia, W. Z.; Hu, Y. K.; Song, Y. Y.; Wang, K.; Xia, X. H. Biosens. Bioelectron. 2008, 23, 892–898. (20) Kohma, T.; Oyamatsu, D.; Kuwabata, S. Electrochem. Commun. 2007, 9, 1012–1016. (21) Xiao, F.; Zhao, F.; Zhang, Y.; Guo, G.; Zeng, B. J. Phys. Chem. C 2009, 113, 849–855. (22) Shan, C.; Yang, H.; Song, J.; Han, D.; Ivaska, A.; Liu, L. Anal. Chem. 2009, 81, 2378–2382. (23) Meng, L.; Wu, P.; Chen, G.; Cai, C. X. J. Electrochem. Soc. 2008, 155, F231– F236. (24) Chen, J.; Bao, J.; Cai, C. X.; Lu, T. Anal. Chim. Acta 2004, 516, 29–34. (25) Liu, S.; Cai, C. X. J. Electroanal. Chem. 2007, 602, 103–114. (26) Du, P.; Liu, S.; Wu, P.; Cai, C. X. Electrochim. Acta 2007, 53, 1811–1823.
Analytical Chemistry, Vol. 81, No. 17, September 1, 2009
7271
biosensor catalyzes the oxidation of glucose to gluconolactone in the presence of oxygen, producing H2O2 simultaneously.13,19,20 Quantification of glucose is achieved via electrochemical oxidation of the liberated H2O2. Nevertheless, the oxidation of H2O2 usually requires a relatively high positive potential (usually over +0.6 V vs SCE).20,29 Many other electroactive species commonly coexisting in the biological fluids, such as ascorbic acid (AA), uric acid (UA), and 4-acetamidophenol (AP), can also be oxidized at such a high potential and their electrochemical signals, thus, severely affect the selectivity of the biosensors. The greatest drawback of these enzymatic glucose sensors is their lack of stability originating from the intrinsic nature of the enzymes, which is hard to overcome. The activity of these enzymes can also be easily affected by temperature, solution pH, humidity, and toxic chemicals. Although GOx is quite stable compared with other enzymes, GOx-based glucose sensors are always exposed to possible thermal and chemical deformation. To address these issues, many attempts have been made to determine glucose without the use of enzymes. The majority of these nonenzymatic electrochemical glucose sensors rely on the current response of glucose oxidation directly at the electrode surface. Early research on this subject have focused on the use of noble metals such as Pt30-32 and Au33,34 for developing nonenzymatic sensors. However, in glucose solution, these electrodes lose their activity quickly by accumulation of chemisorbed intermediates, which block the electrocatalyst surface. In addition, these electrodes often suffer from the influence coming from some electroactive species during electrochemical detection of glucose under physiological conditions.35,36 Nowadays, numerous nanostructured materials have been reported, and their distinguishing characteristics certainly provide new opportunities for developing novel nonenzymatic glucose sensors. For instance, glucose detection has been reported using various nanomaterials as the nonenzymatic electrocatalysts.37-43 These nanomaterials (27) Meng, L.; Wu, P.; Chen, G.; Cai, C. X.; Sun, Y.; Yuan, Z. Biosens. Bioelectron. 2009, 24, 1751–1756. (28) Wu, L.; Zhang, X.; Ju, H. Anal. Chem. 2007, 79, 453–458. (29) Shan, D.; Zhu, M.; Xue, H.; Cosnier, S. Biosens. Bioelectron. 2007, 22, 1612– 1617. (30) Vassilyev, Y. B.; Khazova, O. A.; Nikolaeva, N. N. J. Electroanal. Chem. 1985, 196, 105–125. (31) Beden, B.; Largeaud, F.; Kokoh, K. B.; Lamy, C. Electrochim. Acta 1996, 41, 701–709. (32) Bae, I. T.; Yeager, E. B; Xing, X.; Liu, C. C. J. Electroanal. Chem. 1991, 309, 131–145. (33) Hsiao, M. W.; Adzic, R. R.; Yeager, E. B. J. Electrochem. Soc. 1996, 143, 759–767. (34) Adzic, R. R.; Hsiao, M. W.; Yeager, E. B. J. Electroanal. Chem. 1989, 260, 475–485. (35) Wang, J.; Rivas, G.; Chicharro, M. J. Electroanal. Chem. 1997, 439, 55– 61. (36) Celej, M. S.; Rivas, G. Electroanalysis 1998, 10, 771–775. (37) Male, K. B.; Hrapovic, S.; Liu, Y. L.; Wang, D. S.; Luong, J. H. T. Anal. Chim. Acta 2004, 516, 35–41. (38) Watanabe, T.; Ivandini, T. A.; Makide, Y.; Fujishima, A.; Einaga, Y. Anal. Chem. 2006, 78, 7857–7860. (39) Zhao, W.; Xu, J. J.; Shi, C. G.; Chen, H. Y. Electrochem. Commun. 2006, 8, 773–778. (40) Ohnishi, K.; Einaga, Y; Notsu, H.; Terashima, C.; Rao, T. N.; Park, S. G.; Fujishima, A. Electrochem. Solid-State Lett. 2002, 5, D1–D3. (41) Qiu, R.; Zhang, X. L.; Qiao, R.; Li, Y.; Kim, Y.; Kang, Y. S. Chem. Mater. 2007, 19, 4174–4180. (42) Cui, H. F.; Ye, J. S.; Zhang, W. D.; Li, C. M.; Luong, J. H. T.; Sheu, F. S. Anal. Chim. Acta 2007, 594, 175–183. (43) Park, S.; Boo, H.; Chung, T. D. Anal. Chim. Acta 2006, 556, 46–57.
7272
Analytical Chemistry, Vol. 81, No. 17, September 1, 2009
include mesoporous Pt,44 highly ordered Pt nanotube arrays,45-47 three-dimensional dendritic Pt nanostructures,48 nanoporous Au,49-51 CuO nanowire arrays,52 various alloys such as the nanoporous Pt-Ir alloy,53 Pt-Pb nanoparticles,42 and the Pt-Pb nanoarray,54 boron-doped nanocrystalline diamond thin film,55 and carbon nanotubes (CNTs).56 The immobilization of CNTs and various nanostructures including Pt,57 β-Cu2S,58 SnO2,58 Cu nanocluster,59,60 and so forth on the electrode has also been an important strategy in the construction of nonenzymatic glucose sensors. Among these electrocatalysts, Pt2Pb alloy is a particular one, which generates a larger response and higher sensitivity than those at a pure Pt electrode due to their high surfaceroughness factor and particular nanostructure. In addition, electrooxidation of glucose on such an electrode surface takes place at a remarkable negative potential (-0.15 V vs SCE).61 As a result, interference can be effectively avoided. However, the electrocatalytic activity of this catalyst is seriously poisoned by the presence of chloride ions. The electrocatalytic current is almost entirely suppressed by the presence of only 0.01 M Cl- ion in solution. Also, the Pt2Pb electrocatalyst suffers from the Pb dissolution at a potential of more than +0.4 V (vs SCE). Moreover, most of other electrocatalysts catalyze the oxidation of glucose at a relatively high potential (usually at 0.3-0.65 V vs SCE). Although they retain sufficient sensitivity, the influence from those easily oxidizable species cannot always be effectively avoided.48,49,55,58 Furthermore, most of these electrodes were designed to work under high pH conditions (usually in 0.1 M NaOH solution),50,55,59 which inevitably caused surface degradation and limited the lifetime of the electrocatalysts. Therefore, the development of a suitable catalyst for nonenzymatic glucose detection still remains a challenge. Palladium nanostructures are of great interest due to their extensive applications in gas sensor62 and diverse catalytic fields, (44) Park, S.; Chung, T. D.; Kim, H. C. Anal. Chem. 2003, 75, 3046–3049. (45) Yuan, J. H.; Wang, K.; Xia, X. H. Adv. Funct. Mater. 2005, 15, 803–809. (46) Tang, H.; Chen, J.; Yao, S.; Nie, L.; Deng, G.; Kuang, Y. Anal. Biochem. 2004, 331, 89–97. (47) Hrapovic, S.; Liu, Y.; Male, K. B.; Luong, J. H. T. Anal. Chem. 2004, 76, 1083–1088. (48) Shen, Q.; Jiang, L.; Zhang, H.; Min, Q.; Hou, W.; Zhu, J. J. J. Phys. Chem. C 2008, 112, 16385–16392. (49) Li, Y.; Song, Y. Y.; Yang, C.; Xia, X. H. Electrochem. Commun. 2007, 9, 981–988. (50) Bai, Y.; Yang, W.; Sun, Y.; Sun, C. Sens. Actuators, B: Chem. 2008, 134, 471–476. (51) Yin, H.; Zhou, C.; Xu, C.; Liu, P.; Xu, X.; Ding, Y. J. Phys. Chem. C 2008, 112, 9673–9678. (52) Zhuang, Z.; Su, X.; Yuan, H.; Sun, Q.; Xiao, D.; Choi, M. M. F. Analyst 2008, 133, 126–132. (53) Holt-Hindle, P.; Nigro, S.; Asmussen, M.; Chen, A. Electrochem. Commun. 2008, 10, 1438–1441. (54) Bai, Y.; Sun, Y.; Sun, C. Biosens. Bioelectron. 2008, 24, 579–585. (55) Zhao, J.; Wu, D.; Zhi, J. J. Electroanal. Chem. 2009, 626, 98–102. (56) Ye, J. S.; Wen, Y.; Zhang, W. D.; Gan, L. M.; Xu, G. Q.; Sheu, F. S. Electrochem. Commun. 2004, 6, 66–70. (57) Rong, L. Q.; Yang, C.; Qian, Q. Y.; Xia, X. H. Talanta 2007, 72, 819–824. (58) Myung, Y.; Jang, D. M.; Cho, Y. J.; Kim, H. S.; Park, J.; Kim, J. U.; Choi, Y.; Lee, C. J. J. Phys. Chem. C 2009, 113, 1251–1259. (59) Kang, X.; Mai, Z.; Zou, X.; Cai, P.; Mo, J. Anal. Biochem. 2007, 363, 143– 150. (60) Li, X.; Zhu, Q.; Tong, S.; Wang, W.; Song, W. Sens. Actuators, B: Chem. 2009, 136, 444–450. (61) Sun, Y.; Buck, H.; Mallouk, T. E. Anal. Chem. 2001, 73, 1599–1604. (62) Favier, F.; Walter, E. C.; Zach, M. P.; Benter, T.; Penner, R. M. Science 2001, 293, 2227–2231.
such as electrooxidation of formic acid63-65 and ethanol,66 automotive exhaust purification,67 organic synthesis reaction,68-74 and so forth. However, to our best knowledge, there is no report on the electrocatalytic oxidation of glucose using Pd nanostructures as a catalyst. Herein, we report a study on the nonenzymatic glucose detection based on the Pd-single-walled carbon nanotube (Pd-SWNTs) nanostructure catalyst. The high density of Pd nanoparticles was grown on the surface of SWNTs and characterized with transmission electron microscope (TEM) and X-ray diffraction (XRD) techniques. We fabricated highly sensitive, stable, and fast response amperometric glucose sensors operating at physiological conditions (pH 7.4). The modification of a glassy carbon (GC) electrode with the Pd-SWNT nanostructures increases its active area and promotes the electron transfer for the glucose oxidation reaction via the SWNTs. The Pd-SWNT nanostructures not only catalyze glucose oxidation at a remarkably negative potential in enzyme-free solution but also are insensitive to potential interfering agents such as AA, UA, and AP. This study demonstrates that Pd-SWNT nanostructures can be a potential catalyst in fabricating novel nonenzymatic glucose sensors with high sensitivity, selectivity, and stability. EXPERIMENTAL SECTION Chemicals. PdCl2, glucose, ascorbic acid (AA), uric acid (UA), 4-acetamidophenol (AP), and 3,4-dihydroxyphenylacetic acid (DOPAC) were used as received. Prior to use, SWNTs (
