Electrochemical signal response for vitamin B1 using terbium luminescent nanoscale building blocks as optical sensors

Sensors and Actuators B 188 (2013) 1176–1182

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Sensors and Actuators B: Chemical journal homepage: www.elsevier.com/locate/snb

Electrochemical signal response for vitamin B1 using terbium luminescent nanoscale building blocks as optical sensors Zhan Zhou b , Chaoliang Tan b , Yuhui Zheng b , Qianming Wang a,b,c,∗ a Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China b School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China c Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006, China

a r t i c l e

i n f o

Article history: Received 20 June 2013 Received in revised form 29 July 2013 Accepted 3 August 2013 Available online xxx Keywords: Vitamin B1 Gold Cyclic voltammetry Terbium Nanoprobes

a b s t r a c t A luminescent terbium complex was covalently modified onto anisotropic gold nanostructures (nanoparticles and nanorods) respectively. Two novel emissive gold nanoprobes were successfully developed for selective and rapid determination of vitamin B1 in water. More significantly, electrochemical sensing performances were investigated based on green emissive gold nanoparticles and nanorods which were fabricated by anchoring gold nano-sensors on the surface of glassy carbon electrodes. Both the fluorescence spectra and cyclic voltammetry curves exhibited selective signal changes in the presence of vitamin B1 in comparison with vitamin B2, B3, B4, B5 and B6. It is considered to be the first example that different dimensional fluorescent nano-probes were selected and applied as dual opto-electrochemical sensors for recognizing the same analyte. © 2013 Elsevier B.V. All rights reserved.

1. Introduction Vitamin B1 (thiamine hydrochloride) is an essential nutrient for humans to maintain normal neural activity because the deficiency of it in the diet will lead to the disease known as beri-beri [1,2]. It is significant in preventing such nervous system ailment and practical techniques for the detection of vitamin B1 have been developed. Due to the wide biological role of thiamine, it is essential for the development of a sensitive technology for its determination. Numerous analytical methods have been applied to vitamin B1 measurement, including high-performance liquid chromatography (HPLC) [3–5], resonance Rayleigh scattering [6], electrochemical analysis [7,8], ultraviolet spectrophotometry [9,10], fluorimetric analysis [11,12], etc. Among the methods reported for the determination of thiamine we can point out fluorimetric method had high sensitivity and was simple and rapid for sensing trace vitamin B1. In the field of fluorescent sensors, lanthanide ions as a group of special elements have very narrow emissions with high color purity due to the internal nature of f–f forbidden transitions. More importantly, they have long excited lifetimes that can extend to

∗ Corresponding author at: Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China. Tel.: +86 20 39310258; fax: +86 20 39310187. E-mail address: [email protected] (Q. Wang). 0925-4005/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.snb.2013.08.032

micro-second or even mille-second range which may minimize the influence of background fluorescent signals (usually in the scale of nano-seconds). As far as suitable hosts that could accommodate the luminescent species are concerned, anisotropic gold (Au) nanomaterials have been paid much attention recently and their chemical/physical properties are directly related to their structures [13–17]. It was found that functionalized gold nanomaterials have many potential applications in bio-sensing, intracellular gene regulation, photonics and catalysis, owning to their unique size- and shape-dependence, and optoelectronic properties [18–22]. Concomitantly, it has been shown that lanthanide-based luminescence complexes constituted an emerging class of optical probes that were examined for imaging and sensing of biological analytes [23–28]. Previous studies demonstrated that the potential of lanthanide-based sensors for the optical sensing of biological species can be further improved by attaching lanthanide complexes to nanomaterials, including silica, polystyrene, quantum dots, or carbon nanotubes [29–32]. More specifically, the combination of luminescent species with AuNPs for the development of nanohybrids has been achieved and enhanced photo-luminescent and sensing performances can be observed [33–35]. Another fascinating property of gold materials is their outstanding conductivities, which endowed them with great potential as electrode materials. Therefore, the application of gold nanomaterials in electrochemical sensors has gained a great deal of interests in recent years because of their good catalysis, stability,

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and biocompatibility [20–22]. Herein, two novel terbium-based Au nanoprobes (AuNP-TbM-EDTA and AuNR-TbM-EDTA) with regular shapes were designed by covalently grafting the sensing moiety (terbium complex), which have characteristic green luminescence, onto the surface of 0D and 1D gold nanostructures. Luminescence quenching effects of both target materials can be rapidly observed in the presence of vitamin B1 but not vitamin B2, B3, B4, B5 and B6. The detailed molecular structures of these analytes were given in Fig. S1. More significantly, the two sensing materials were loaded onto the glassy carbon (GC) electrodes and their sensing properties were studied through electrochemical measurements. We discovered that only vitamin B1 could give rise to electric potential signal changes during the redox processes. Therefore, terbium-based 0D and 1D Au nanoprobes showed potential applications as dual signal (opto-electrochemical) sensors in the detection of vitamin B1. 2. Experimental

Fig. 1. Schematic representation of the luminescent terbium complex covalently modified gold nanoparticles (AuNP-TbM-EDTA) and nanorods (AuNR-TbM-EDTA).

2.1. Materials and methods All solvents and chemicals were purchased from commercial sources and used without further purification. Tb4 O7 (99.9%) was purchased from Shanghai yuelong company. Terbium perchlorate was obtained by dissolving Tb4 O7 in concentrated perchloric acid [36]. Vitamin B1, B2, B3, B4, B5 and B6 were purchased from Sigma–Aldrich. 11-Mercaptoundecanoic acid, ethylenediaminetetraacetic acid and 4-(dimethylamino)pyridine (DMAP) were purchased from TCI. Unless otherwise stated, all measurements were performed at 298 K. UV–vis absorption spectra were measured in 1 cm quartz cuvettes on Agilent 8453 spectrophotometer and baseline correction was applied for all spectra. Fluorescence spectra were recorded on an Edinburgh FLS920 spectrometer. TEM was measured using a JEOL JEM-2100HR transmission electron microscope. Voltammetric measurements (including cyclic voltammetry and differential pulse voltammetry) were performed on a CHI660a electrochemical system with a corresponding software package. Elemental analyses of C, H, N and S were determined with a Thermo FlashEA112 elemental analyzer. 2.2. Synthesis of terbium complex functionalized gold nanoparticle (AuNPs) and nanorods (AuNRs) AuNPs and AuNRs were prepared according to a previously published method [37]. Ethylenediaminetetraacetic acid (EDTA, 29.2 mg, 0.1 mmol), 11-mercaptoundecanoic acid (MA, 21.8 mg, 0.1 mmol) and Tb(ClO4 )3 ·6H2 O (56.3 mg, 0.1 mmol) were dissolved in 10 mL ethanol, and the whole mixture was titrated by 3–5 drops of aq. NH3 ·H2 O and was refluxed at 90 ◦ C for 1 h. Then it was cooled to room temperature. The resulting precipitate was collected and washed twice with water to give the titled complex (TbM-EDTA) as white powder. EA found C21 H33 N2 O10 STb: C, 37.74; H, 5.02; N, 4.41; S, 4.75%, Anal. Calcd for: C, 37.96; H, 5.01; N, 4.22; S, 4.83%. Chemical modification of TbM-EDTA on AuNRs and AuNRs were performed by the two-phase Brust method which gave 4-(dimethylamino)pyridine (DMAP) stabilized gold nanoparticles (DMAP-AuNPs) and nanorods (DMAP-AuNRs) [35,38,39]. Briefly, exchange of DMPA on the surface of AuNPs/AuNRs with the terbium complex was achieved upon stirring DMAP-AuNPs/DMAP-AuNRs with TbM-EDTA for 12 h at room temperature, followed by centrifugation and washed with water three times to remove any unbound TbM-EDTA. The obtained two probes were noted AuNP-TbM-EDTA and AuNR-TbM-EDTA, respectively. In order to estimate the number of bound Tb complexes per AuNP (or AuNR), the terbium binary complex,

11-mercaptoundecanoic acid terbium (TbM), was attached onto the surface of AuNP/AuNR to obtain water soluble gold nanoparticles (AuNP-TbM)/nanorods (AuNR-TbM) in the similar process. 2.3. Preparation of AuNP-TbM-EDTA and AuNR-TbM-EDTA modified glassy carbon (GC) electrodes Prior to the preparation of gold nanomaterials modified GC electrode, the GC disk electrode (3 mm in diameter, 0.071 cm2 ) was polished with 3 ␮m and 0.1 ␮m alumina paste on a polishing cloth (Buehler) and then subjected to ultrasonic cleaning for about 10 min in distilled water [40]. The AuNP-TbM-EDTA/AuNRTbM-EDTA suspension was prepared by dispersing 5 mg AuNPs or AuNRs in 5 mL water with the aid of ultrasonic agitation. Next, the modified electrode was prepared by dropping 5 ␮L above solution onto the GC electrode surface. Then the solvent was evaporated under an infrared lamp. The electrode properties were tested in a three-electrode system using the prepared electrodes as working electrode, Pt as the auxiliary electrode, Ag/AgCl as the reference electrode in the range of 0–1.4 V at a sweep rate of 0.1 V s−1 . And the buffer solution was 10 mmol L−1 Tris/50 mmol L−1 NaCl of pH 7.2, prepared with doubly distilled water. 3. Results and discussion Because the surface of gold nanomaterials owns high affinity for sulfur atom, so 11-mercaptoundecanoic acid was applied as linkages through Au-S bond to graft terbium complex onto 0D and 1D Au nanostructures. It is noteworthy that 11-mercaptoundecanoic acid has a long and soft alkyl chain, which will be beneficial for the attachment. Meanwhile, it could coordinate terbium ions firmly to obtain AuNP-TbM and AuNR-TbM. However, both of them were restricted by instability in water due to the unsaturation of terbium ion. Therefore, in order to satisfy coordinated number, a frequently used ethylenediaminetetraacetic acid (EDTA) was applied as a second ligand to coordinate with terbium ion. The target materials, AuNP-TbM-EDTA and AuNR-TbM-EDTA, which had intense green emission, were successfully prepared (see the synthetic process in Fig. 1). The covalent functionalization of terbium complex onto Au nanomaterials was evidenced by UV–vis spectroscopy. Spectra of pure Au nanoparticles and nanorods had two broad absorption bands around 250 and 530 nm (Fig. 2); however, a new band can be detected in the spectra of AuNP-TbM-EDTA and AuNR-TbMEDTA, which may correspond to the terbium complex (Fig. 2, inset). The amount of bound terbium (III) complexes per AuNP/AuNR

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intensity / a.u.

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AuNPs AuNPs

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300

300

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400

530 nm

400

500

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wavelength / nm Fig. 2. UV–vis spectra of the gold nanoparticles, nanorods, AuNP-TbM-EDTA and AuNR-TbM-EDTA. Inset: UV–vis spectrum of terbium complex. Spectra were recorded in water at 1 mg/L.

was estimated to be ca. 280/350 (Figs. S2 and S3, further details were described in Supporting Information) [35,41]. These results proved the terbium complex had been loaded onto the surface of Au nanostructures. Stability experiments were also carried out. Fig. S4 shows the dependence of integrated intensity ratio on the time duration (100 h). The results indicated that the leaching of the emissive species in the hybrid material could be avoided and the reduction in luminescence ratio was within 5%. The morphology of AuNP-TbM-EDTA and AuNR-TbM-EDTA were studied by transmission electron microscopy (TEM). The functionalized Au nanoprobes were stable in solution, and no aggregation was observed after several days. Mono-dispersed spherical nanoparticles with diameter about 10–20 nm were clearly observed (Fig. 3a). TEM image of AuNR-TbM-EDTA indicated the presence of distributed nanorods with an average diameter of ∼10 nm and length of 30–50 nm (Fig. 3b). It has been shown that chemical modification of terbium complex on Au nanomaterials had insignificant influence on their morphology. The photoluminescence and sensing abilities of AuNP-TbMEDTA were investigated by fluorescence spectroscopy (1 mg/L in H2 O). The excitation spectrum was characterized by a broad band from 220 to 260 nm with maximum at 238 nm, which was recorded by fixing the emission wavelength of the Tb3+ at 547 nm (Fig. 4a, inset). Narrow-width emission bands (ex = 238 nm) with maxima at 492, 547, 587, and 625 nm can be observed in Fig. 4a. These bands are attributed to the 5 D4 → 7 F6 , 5 D4 → 7 F5 , 5 D4 → 7 F4 , and

Fig. 4. Emission spectra of AuNP-TbM-EDTA (1 mg/L, ex = 238 nm) upon addition of 0 to 10−4 M vitamin B1 in water (a). Inset: excitation spectrum of AuNP-TbMEDTA (em = 547 nm). Relative intensity of AuNP-TbM-EDTA at 547 nm with the concentration over a vitamin B1 concentration range from 5 × 10−6 to 10−4 M (b).

5D 4

→ 7 F3 transitions of Tb3+ ions, respectively. Upon the addition of vitamin B1 at concentrations ranging from 5 × 10−6 to 10−4 mol L−1 , the emission intensities from AuNP-TbM-EDTA were rapidly quenched. The relative value of luminescence decreased from 976 to 85 within 2–3 s due to the addition of vitamin B1. The detection limit was calculated according to the equation DL = 3 × SD/slope [42]. SD corresponds to the standard deviation of the blank sample (obtained by 10 consecutive scans of the blank sample). Accordingly, the detection limit of this probe for vitamin B1 is 5.2 × 10−7 M (Fig. 4b).

Fig. 3. Transmission electron microscope of AuNP-TbM-EDTA (a) and AuNR-TbM-EDTA (b).

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Fig. 5. Progressive DPVs of AuNP-TbM-EDTA (a) and AuNR-TbM-EDTA (b) upon the addition of vitamin B1 at different pH values.

Similarly, the sensing capability of AuNR-TbM-EDTA was also studied through fluorescence spectroscopy (Fig. S5a). The excitation of AuNR-TbM-EDTA was very similar to AuNP-TbM-EDTA, as shown in Fig. S5a (insert). In its emission spectrum, Tb3+ emissions in both cases were evident from the appearance of line-like emission bands at 492, 547, 587, and 625 nm, respectively, corresponding to the deactivation of the Tb3+ excited states 5 D4 → 7 FJ (J = 6, 5, 4 and 3) (excited at 238 nm). In a similar fashion, the gradual quenching effects of AuNR-TbM-EDTA can be detected upon the addition of vitamin B1 from 5 × 10−6 to 10−4 mol L−1 . According to the same calculations, the detection limit of this probe for vitamin B1 is 6.3 × 10−7 M (Fig. S5b). It can be seen that there was not too much difference for the detection limits between the two morphological materials. Analogous experiments for AuNP-TbM-EDTA and AuNR-TbMEDTA in the presence of concentrated vitamin B2, B3, B4, B5, or B6 (10−4 M) water solution were explored by fluorescence spectroscopy. Only minor changes were observed in the emission spectra after adding these analytes (Figs. S6 and S7, black bars). When we added 10−4 M of vitamin B1 to the above solution, it gave rise to drastic quenching in accordance with the addition of 10−4 M of vitamin B1 alone (Figs. S6 and S7, gray bars). These observations indicate that both AuNP-TbM-EDTA and AuNR-TbM-EDTA have an excellent selectivity to vitamin B1, and the response process was not disturbed by other vitamin B. This undesired efficient deactivation of terbium luminescence has been discussed and several reasons may contribute to these sensing processes. It is known that the inner-shell 4f-4f transitions of lanthanide ions are forbidden and the usually observed energy migration path goes through the harvested energy from coordinated ligands [43,44]. If the added analytes could interfere with the sensitization processes or affect the energy absorbed by the organic ligands, the metal-centered luminescence derived from antenna effects would be substantially reduced. Here we investigated the titration experiments between ligand EDTA and the six kinds of vitamins (VB1 to B6). It has been found that only vitamin B1 could induce emission quenching effects of the ligand (Fig. S8). Then the intra-molecular energy transfer was restricted because the emitted light of the organic fluorophore has been dissipated. Finally, the terbium emission was quenched. In addition, vitamin B1 possessed larger ring systems and size compared with vitamin B3, B4 and B5. Moreover, the methylene group between the two heterocyclic rings will allow the two moieties more flexible. They may have chances to rotate and disturb the coordination interactions of original terbium complex. It was mentioned before in the literature that the high frequency vibrations such as NH2 would dissipate the lanthanide emissions [45], so the emission from terbium ions might partially be quenched by NH2 group from VB1. Certainly, the acidity

of vitamin B1 may be also involved in the luminescence changes. But this reason was not the decisive factor because we have carried out the luminescence detection experiments in buffer solution (0.1 M) at pH = 7.4 in order to rule out the influence of pH changes. Facts proved that the two terbium-based Au nanoprobes still could have responses to vitamin B1. The detection limits (AuNP-TbMEDTA 8.5 × 10−5 M, AuNR-TbM-EDTA 9.6 × 10−5 M) were relatively higher than in water (AuNP-TbM-EDTA 5.2 × 10−7 M, AuNR-TbMEDTA 6.3 × 10−7 M) (Figs. S9 and S10). Electrochemical analysis technique as a practical method has been widely applied in chemical and biological analysis in recently years. It is well accepted that gold is a classic noble metal, which possesses excellent conductivity. Consequently, gold nanomaterials as electrode materials have generated a great deal of interests in the field of electrochemistry. Au nanoprobes are considered as striking candidates for nano-electrodes. The two nanoprobes were successfully assembled onto GC electrodes and their electrochemical sensing properties were tested in a three-electrode system using Pt as the auxiliary electrode, Ag/AgCl as the reference electrode. Differential pulse voltammetry (DPV; pulse width 0.05 s, step potential 4 mV, amplitude 25 mV) was used to carry out the electrochemical performance of the functionalized GC electrodes. The differential pulse voltammograms (DPVs) of AuNP-TbMEDTA (or AuNR-TbM-EDTA) in the presence of vitamin B1 (10 ␮M) at different pH value solutions are shown in Fig. 5a and b. When the pH value was remained to be 7.2, the oxidative wave grows gradually with the increasing concentration of vitamin B1. Particularly, under the alkaline environment (pH 9.0), it was observed that the significant difference of anodic peak potentials. It is accepted that vitamin B1 is stable at acidic pH, but is unstable in alkaline solutions [46]. Therefore, in order to maintain the stability of vitamin B1 and the appropriate biological environment, we chose the pH buffer solution as 7.2. Cyclic voltammogram (CV) was utilized to investigate the electrochemical behavior of 10 ␮M vitamin B1 in Tris buffer solution (pH 7.2) with a bare GCE (Fig. 6), an AuNP-TbM-EDTA/GCE and an AuNR-TbM-EDTA/GCE at a sweep rate of 0.1 V s−1 . Two anodic and cathodic peak potentials were observed in the potential range from 0 to 1.4 V, revealing that vitamin B1 underwent a quasi reversible process on the electrodes. The CV of vitamin B1 showed a weak oxidation peak at 0.401 V on the bare glass carbon electrode (abbreviated as GCE). On the AuNP-TbM-EDTA/GCE or AuNP-TbMEDTA/GCE, more intense oxidation wave occurred at 0.430 V or 0.542 V with a positive shift of 0.029 V or 0.141 V, showing the electro-chemical active effect of the AuNP-TbM-EDTA/AuNR-TbMEDTA will reinforce the signal response. In detail, the oxidation on the two catalytic surfaces showed 1.4-fold (AuNP-TbM-EDTA/GCE) and 2.1-fold (AuNR-TbM-EDTA/GCE) enhancement in the peak current compared with the bare GCE, which can be related to the

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I/A

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E/V Fig. 6. CV of GC (black solid line), AuNPs/GCE (red dot line), AuNP-TbM-EDTA/GCE (red solid line), AuNRs/GCE (blue dot line) and AuNR-TbM-EDTA/GCE (blue solid line) in the presence of 10 ␮M vitamin B1 in the Tris buffer (pH = 7.2) with a scan rate of 0.1 V s−1 . (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

specific catalytic effect of nano-Gold. It is estimated that the incorporation of terbium inorganic–organic hybrid structures might facilitate the electron transfer and the bonded chemical species would have a significant influence on the interface properties of the electrode or accelerate the electron transfer efficiency (Fig. S11). The surface of gold particles was attached by numerous terbium trivalent cation (electron deficient) and organic molieties such as EDTA and 11-mercaptoundecanoic acid which could have more chances to entrap large amounts of electrons. Therefore, the affinity to electrons would improve and the electrochemical responses were enhanced. For the sake of confirming this point, we also carefully studied the redox processes of pure gold nanoprobes (both nanoparticle and nanorod). The peak currents were much lower than the terbium complex containing hybrid materials (Fig. 6). It firmly supported that the covalently bonded organic structures and terbium ions may fasten rapid transport of electrons and induce the improvement of electrochemical properties. CVs were also applied to check the relationship between the peak currents and the amounts of AuNP-TbM-EDTA/AuNR-TbMEDTA on the GCE. The oxidation peak currents (Fig. 7a and b) increased stepwise when the amounts of AuNP-TbM-EDTA/AuNRTbM-EDTA in the suspension increased from 1 to 5 ␮L. When we continued to increase the concentration (10 ␮L), the peak current

a b

Current / μΑ

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Fig. 8. Cyclic voltammograms of AuNP-TbM-EDTA assembled on a GC electrode in the presence of 0.1 to 10 ␮M vitamin B1 in the buffer solution (pH = 7.2). Inset shows the relations of anodic peak currents (peak A) with the concentration of vitamin B1 (CVB1 ).

went down gradually. This phenomenon may be caused by the thicker Gold film that will restrict the efficiency of electrical conductivity. A close examination for the electrochemical sensing of vitamin B1 was performed. As shown in Fig. 8, the redox signals of AuNPTbM-EDTA/GCE were responsive to the increasing concentrations of vitamin B1. Both the oxidation and reduction currents increased gradually upon addition of vitamin B1 from 0.1 to 10 ␮M. This result suggests that the electrochemical signal of AuNP-TbM-EDTA/GCE depends on the vitamin B1 concentration as indicated by the relation curve in the inset of Fig. 8, with the detection limit of 80 nM based on S/N = 3. Similarly, we also investigated the electrochemical properties of AuNR-TbM-EDTA at GC electrode under the same condition. The signal responses of AuNR-TbM-EDTA were similar to AuNP-TbM-EDTA in the presence of vitamin B1 (Fig. S12), while its detection limit (10 nM) was much lower than that of AuNP-TbMEDTA. It is proposed that 1D dimensional nanostructure with large aspect ratio will speed up the diffusion process and increase the electron transfer rates. The effect of other vitamins on the peak current of a solution containing of 1 ␮M vitamin B1 was evaluated. The signal changes for B2, B3, B4, B5 and B6 (the concentrations of B2–B6 were 10 ␮M) were within 4% and the corresponding curves were provided in Figs. S13 and S14. The related reference methods and their results were also compared and summarized in Table S1 [3,5–12]. Although the detection limits of some fluorimetry approaches were even lower than the hybrid terbium luminescent sensors, these terbium-based Au nanoprobes still needs to be studied due to their specific optical properties. Firstly, the long-lived lanthanide luminescence would be readily distinguished from most of the short-lived (nanoseconds scale) background signals in future practical systems. Secondly, the narrow emissive bands of terbium ions with high color purity might be more sensitive to human eyes compared with normal broad band emissions. 4. Conclusions

0 0

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Volume / μL Fig. 7. The relationship between the amount of AuNP-TbM-EDTA (a)/AuNR-TbMEDTA (b) and the oxidation peak current of 10 ␮M vitamin in Tris buffer (pH 7.2).

In summary, we have demonstrated the design and synthesis of terbium complex functionalized 0D and 1D nanoprobes for the rapid and selective detection of vitamin B1 in aqueous solution. Luminescence quenching effects of these sensing materials can be rapidly observed in the presence of vitamin B1 compared with vitamin B2, B3, B4, B5 and B6. More importantly, the two nanosensors were assembled on GC electrodes and their cyclic voltammogram

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curves also exhibited signal changes toward vitamin B1. These opto-electrochemical sensors used in this system provided a potential way for vitamin B1 measurement in biological science. Acknowledgments This study was supported by the Scientific Research Foundation of Graduate School of South China Normal University. (2012kyjj240). Q.M. appreciates National Natural Science Foundation of China (21002035). Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.snb.2013.08.032. References [1] R.D. Williams, H.L. Mason, R.M. Wilder, B.F. Smith, Observations on induced thiamine (vitamin B1) deficiency in man, Arch. Intern. Med. 66 (1940) 785–799. [2] B.C. James, G. Knight, The nutrition of Staphylococcus aureus; nicotinic acid and vitamin B1 , BioChem. J. 31 (1937) 731–737. [3] C.K. Markopoulou, K.A. Kagkadis, J.E. Koundourellis, An optimized method for the simultaneous determination of vitamins B1 , B6 , B12 , in multivitamin tablets by high performance liquid chromatography, J. Pharm. Biomed. Anal. 30 (2002) 1403–1410. [4] P.L.M. Lynch, I.S. Young, Determination of thiamine by high-performance liquid chromatography, J. Chromatogr. A 881 (2000) 267–284. ´ [5] M.L. Marszałł, A. Lebiedzinska, W. Czarnowski, P. Szefer, High performance liquid chromatography method for the simultaneous determination of thiamine hydrochloride, pyridoxine hydrochloride and cyanocobalamin in pharmaceutical formulations using coulometric electrochemical and ultraviolet detection, J. Chromatogr. A 1094 (2005) 91–98. [6] S.P. Liu, Z.Y. Zhang, H.Q. Kong, Resonance Rayleigh-scattering method for the determination of Vitamin B1 with methyl orange, Anal. Sci. 18 (2002) 971–976. [7] J. Oni, P. Westbroek, T. Nyokong, Voltammetric detection of vitamin B1 at carbon paste electrodes and its determination in tablets, Electroanalysis 14 (2002) 1165–1168. [8] B. Huang, B.Z. Yu, P.B. Li, M. Jiang, Y.S. Bi, S.F. Wu, Vitamin B1 ion-selective microelectrode based on a liquid–liquid interface at the tip of a micropipette, Anal. Chim. Acta 312 (1995) 329–335. [9] P. Ortega-Barrales, M.L. Fernández-de Córdova, A. Molina-Díaz, Microdetermination of vitamin B1 in the presence of vitamins B2, B6, and B12 by solid-phase UV spectrophotometry, Anal. Chem. 70 (1998) 271–275. [10] S. liu, Z. Zhang, Q. Liu, H. Luo, W. Zheng, Spectrophotometric determination of vitamin B1 in a pharmaceutical formulation using triphenylmethane acid dyes, J. Pharm. Biomed. Anal. 30 (2002) 685–694. [11] J. López-Flores, M.L. Fernández-De Córdova, A. Molina-Díaz, Implementation of flow-through solid phase spectroscopic transduction with photochemically induced fluorescence: determination of thiamine, Anal. Chim. Acta 535 (2005) 161–168. [12] T. Pérez-Ruiz, C. Martínez-Lozano, V. Tomas, I. Ibarra, Flow injection fluorimetric determination of thiamine and copper based on the formation of thiochrome, Talanta 39 (1992) 907–911. [13] X. Huang, X.Y. Qi, Y.Z. Huang, S.Z. Li, C. Xue, C.L. Gan, F. Boey, H. Zhang, Photochemically controlled synthesis of anisotropic Au nanostructures: platelet-like Au nanorods and six-star Au nanoparticles, ACS Nano 4 (2010) 6196–6202. [14] Z.Y. Huo, C.K. Tsung, W.Y. Huang, X.F. Zhang, P.D. Yang, Sub-Two nanometer single crystal Au nanowires, Nano Lett. 7 (2008) 2041–2044. [15] T.K. Sau, C.J. Murphy, Synthesis of multiple shapes of gold nanoparticles in aqueous solution, J. Am. Chem. Soc. 126 (2004) 8648–8649. [16] X.M. Lu, M.S. Yavuz, H.Y. Tuan, B.A. Korgel, Y.N. Xia, Ultrathin gold nanowires can be obtained by reducing polymeric strands of oleylamine–AuCl complexes formed via aurophilic interaction, J. Am. Chem. Soc. 130 (2008) 8900–8901. [17] X. Huang, S.Z. Li, Y.Z. Huang, S.X. Wu, X.Z. Zhou, S.Z. Li, C.L. Gan, B. Freddy, C.A. Mirkin, H. Zhang, Synthesis of hexagonal close-packed gold nanostructures, Nat. Commun. 2 (2011) 292–293. [18] M. Hu, J.Y. Chen, Z.Y. Li, L. Au, G.V. Hartland, X.D. Li, M. Marquez, Y.N. Xia, old nanostructures: engineering their plasmonic properties for biomedical applications, Chem. Soc. Rev. 35 (2006) 1084–1094. [19] N.L. Rosi, D.A. Giljohann, C.S. Thaxton, A.K.R. Lytton-Jean, M.S. Han, C.A. Mirkin, Oligonucleotide-modified gold nanoparticles for intracellular gene regulation, Science 312 (2006) 1027–1030. [20] R. Narayanan, M.A. El-Sayed, Catalysis with transition metal nanoparticles in colloidal solution: nanoparticle shape dependence and stability, J. Phys. Chem. B 109 (2005) 12663–12676.

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[21] J.E. Millstone, S.J. Hurst, G.S. Metraux, J.I. Cutler, C.A. Mirkin, Colloidal gold and silver triangular nanoprisms, Small 5 (2009) 646–664. [22] C. Wang, Y. Hu, C.M. Lieber, S. Sun, Ultrathin Au nanowires and their transport properties, J. Am. Chem. Soc. 130 (2008) 8902–8903. [23] J-C.G. Bunzli, Lanthanide luminescence for biomedical analyses and imaging, Chem. Rev. 110 (2010) 2729–2755. [24] M.I.J. Stich, M. Schaeferling, O.S. Wolfbeis, Multicolor fluorescent and permeation-selective microbeads enable simultaneous sensing of pH, oxygen, and temperature, Adv. Mater. 21 (2009) 2216–2220. [25] C.P. Montgomery, B.S. Murray, E.J. New, R. Pal, D. Parker, Cell-penetrating metal complex optical probes: targeted and responsive systems based on lanthanide luminescence, Acc. Chem. Res. 42 (2009) 925–937. [26] C.L. Tan, Q.M. Wang, C.C. Zhang, Optical and electrochemical responses of an anthrax biomarker based on single-walled carbon nanotubes covalently loaded with terbium complexes, Chem. Commun. 47 (2011) 12521–12523. [27] B. Song, G.L. Wang, M.Q. Tan, J.L. Yuan, Europium(III) complex as an efficient singlet oxygen luminescence probe, J. Am. Chem. Soc. 128 (2006) 13442–13450. [28] H. Tsukube, S. Shinoda, Lanthanide complexes in molecular recognition and chirality sensing of biological substrates, Chem. Rev. 102 (2002) 2389–2403. [29] H. Zhang, Y. Xu, W. Yang, Q. Li, Dual-lanthanide-chelated silica nanoparticles as labels for highly sensitive time-resolved fluorometry, Chem. Mater. 19 (2007) 5875–5881. [30] C. Vancaeyzeele, O. Ornatsky, V. Baranov, L. Shen, A. Abdelrahman, M.A. Winnik, Lanthanide-containing polymer nanoparticles for biological tagging applications: nonspecific endocytosis and cell adhesion, J. Am. Chem. Soc. 129 (2007) 13653–13660. [31] L.J. Charbonniere, N. Hildebrandt, R.F. Ziessel, H.G. Loehmannsroeben, Lanthanides to quantum dots resonance energy transfer in time-resolved fluoro-immunoassays and luminescence microscopy, J. Am. Chem. Soc. 128 (2006) 12800–12809. [32] Q.M. Wang, C.L. Tan, W.S. Cai, A targetable fluorescent sensor for hypochlorite based on a luminescent europium complex loaded carbon nanotube, Analyst 137 (2012) 1872–1875. [33] B.I. Ipe, K. Yoosaf, K.G. Thomas, Functionalized gold nanoparticles as phosphorescent nanomaterials and sensors, J. Am. Chem. Soc. 128 (2006) 1907–1913. [34] S. Comby, T. Gunnlaugsson, Luminescent lanthanide-functionalized gold nanoparticles: Exploiting the interaction with bovine serum albumin for potential sensing applications, ACS Nano 5 (2011) 7184–7197. [35] J. Massue, S.J. Quinn, T. Gunnlaugsson, Lanthanide luminescent displacement assays: the sensing of phosphate anions using Eu(III) cyclen-conjugated gold nanoparticles in aqueous solution, J. Am. Chem. Soc. 130 (2008) 6900–6901. [36] Z. Zhou, Q.M. Wang, Two emissive cellulose hydrogels for detection of nitrite using terbium luminescence, Sens. Actuators B: Chem. 173 (2012) 833–838. [37] T.K. Sau, C.J. Murphy, Seeded high yield synthesis of short Au nanorods in aqueous solution, Langmuir 20 (2004) 6414–6420. [38] V.J. Gandubert, R.B. Lennox, Assessment of 4-(dimethylamino)pyridine as a capping agent for gold nanoparticles, Langmuir 21 (2005) 6532–6539. [39] D.I. Gittins, F. Caruso, Spontaneous phase transfer of nanoparticulate metals from organic to aqueous media, Angew. Chem. Int. Ed. 40 (2001) 3001–3004. [40] W.Y. Zou, L. Wang, B.Y. Lu, H. Li, H.Y. Chen, Electrochemical assembly of [Ru(bpy)2 tatp]2+ associated with surfactants on the MWNTs/GC electrode, J. Appl. Electrochem. 39 (2009) 2015–2020. [41] L.K. Truman, S. Comby, T. Gunnlaugsson, pH-responsive luminescent lanthanide-functionalized gold nanoparticles with on–off ytterbium switchable near-infrared emission, Angew. Chem. Int. Ed. 51 (2012) 9624–9627. [42] H.T. Niu, D. Su, X. Jiang, W. Yang, Z. Yin, J. He, J.P. Cheng, A simple yet highly selective colorimetric sensor for cyanide anion in an aqueous environment, Org. Biomol. Chem. 6 (2008) 3038–3040. [43] J.C.G. Bunzli, C. Piguet, Taking advantages of luminescent lanthanide ions, Chem. Soc. Rev. 34 (2005) 1048–1077. [44] R.D. Archer, H.Y. Chen, L.C. Thompson, Synthesis, characterization and luminescence of europium (III) schiff base complexes, Inorg. Chem. 37 (1998) 2089–2095. [45] E. Brunet, O. Juanes, J.C. Rodriguez-Ubis, Supramolecularly organized lanthanide complexes for efficient metal excitation and luminescence as sensors in organic and biological applications, Curr. Chem. Biol. 1 (2007) 11–39. [46] L.K. Mahan, S. Escott-Stump, Krause’s Food, Nutrition, & Diet Therapy, W.B. Saunders Company, Philadelphia, 2000.

Biographies Zhan Zhou obtained his bachelor degree in chemistry Department of Shang Qiu Normal University, Henan, China (July, 2010). From September, 2010, he continued his master degree at South China Normal University under the supervision of Prof. Qianming Wang. His current research interests include the synthesis and assembly of smart lanthanide luminescent sensors. Chaoliang Tan obtained his master degree (July, 2012) in School of Chemistry and Environment of South China Normal University under the supervision of Prof. Qianming Wang. His main interests are focused on optical functional materials design and construction.

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Yuhui Zheng obtained her master degree (July, 2009) in Nanchang Hangkong University under the supervision of Prof. Huan Yu. Her main interests in South China Normal University are concentrated on smart responsive materials preparation and applications. Qianming Wang was educated at Tongji University (Shanghai, P.R. China) and received his doctor degree in December 2006. Then he continued the post-doc

research in Ritsumeikan University (Kusatsu, Japan) supported by Japan Society for the Promotion of Science (JSPS) until April 2009. He participated in South China Normal University (Guangzhou, P.R. China) since July of 2009 and has been a Professor of Chemistry since January 2010. He is the author of more than 80 peer-reviewed articles in this field. His research interests are lanthanide functional materials and sensors.