Research Article Electrochemiluminescence Biosensor Based...

Research ArticleElectrochemiluminescence Biosensor Based onThioglycolic Acid-Capped CdSe QDs for Sensing Glucose

Eun-Young Jung,1 Jun-Hee Ye,1 Sung-Hee Jung,2 and Seong-Ho Choi1

1Department of Chemistry, Hannam University, Daejeon 305-811, Republic of Korea2Division of Radioisotope R&D, Korea Atomic Energy Research Institute, Daejeon 305-600, Republic of Korea

Correspondence should be addressed to Seong-Ho Choi; [email protected]

Received 19 February 2016; Revised 18 August 2016; Accepted 25 October 2016

Academic Editor: Marinella Striccoli

Copyright © 2016 Eun-Young Jung et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited.

In order to detect low level glucose concentration, an electrochemiluminescence (ECL) biosensor based on TGA-capped CdSequantum dots (QDs) was fabricated by the immobilization of CdSe QDs after modifying the surface of a glassy carbon electrode(GCE) with 4-aminothiophenol diazonium salts by the electrochemical method. For the detection of glucose concentration,glucose oxidase (GOD) was immobilized onto the fabricated CdSe QDs-modified electrode.The fabricated ECL biosensor based onTGA-capped CdSe QDs was characterized using a scanning electron microscope (SEM), UV-vis spectrophotometry, transmissionelectron microscopy (TEM), a fluorescence spectrometer (PL), and cyclic voltammetry (CV). The fabricated ECL biosensor basedon TGA-capped CdSe QDs is suitable for the detection of glucose concentrations in real human blood samples.

1. Introduction

Electrogenerated chemiluminescence (ECL) has become animportant and valuable detectionmethod in analytical chem-istry in recent years [1]. ECL is well known because ofits good stability against photo bleaching, high sensitivity,favorable spatial qualities, time controllability, low cost, andlow background noise. Since the first detailed studies in themid-1960s, over 1000 papers, patents, and book chapters havebeen published on ECL, ranging from the very fundamentalto the very applied. Recently, ECL has been used exten-sively as a powerful analytical tool in many areas such asimmunoassay [2–4], clinical diagnosis [5, 6], and the analysisof food and water [7]. Luminophores can be divided intoorganic and inorganic luminophores such as luminol, luci-genin, tris(bipyridine)ruthenium(II), and Ru(bpy)

3

2+, andthey have been widely used in immunoassay and DNAanalysis because they result in light emission and allow fordetection of the emitter at very low concentrations [8, 9].

Semiconductor nanocrystals such as quantumdots (QDs)have attracted considerable interest because of the advantagesof their size-dependent electronic and optic properties, whichhave been extensively studied and applied in recognition

and detection in biometry [10, 11]. A remarkable increasein ECL intensity has been reported for quantum dot (QD)composites with carbon nanotubes deposited on electrodesurfaces, graphene, carbon paste electrodes, and nanopar-ticles. Among the detection techniques in the biomedicalfield, ECLs based on a QD system have been known foroffering a wide range of advantages such as broad excitationspectra, narrow emission spectra, and low cost [12–14]. Ina previous paper, we also prepared an ECL biosensor usingCdSe QDs as a luminophore for detection of acetylcholinein human blood. In this experiment, we used L-cystein asthe capping chemicals of the QD surface [15]. However, withL-cystein as the capping chemicals, there is a decrease ofECL intensity because of quenching effects. Therefore, thereis a need for advanced CdSe QDs with capping chemicalswithout quenching effects to enable the effective use ofluminophore materials. Furthermore, we need an easy andsimple preparation method of CdSe QDs.

In this study, a novel ECL biosensor based on thioglycolicacid- (TGA-) capped CdSe QDs was prepared to provideimproved sensitivity, selectivity, serviceability, and stabilityalong with low cost. First, the TGA-capped CdSe QDs weresynthesized in an aqueous solution using thioglycolic acid

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2016, Article ID 5760327, 9 pageshttp://dx.doi.org/10.1155/2016/5760327

2 Journal of Nanomaterials

SH SH

GCE

MWNT

MWNT/GCE

N≡N+Cl−

SH SH

SH/MWNT/GCE

QDs Glucose oxidase

CdSe/SH/MWNT/GCE GOD-immobilized biosensor

Scheme 1: Preparation procedure of the glucose oxidase- (GOD-) immobilized biosensor based on QDs.

(TGA). An ECL biosensor based on TGA-capped CdSeQDs was prepared by the modification of the GCE withmultiwalled carbon nanotubes (MWNTs) and TGA-cappedCdSe QDs, and then glucose oxidase (GOD) was immobilizedon the surface for reaction with glucose. Furthermore, thefabricated ECL biosensor can be applied to the quantitativeand qualitative analysis of glucose concentration.

2. Experimental

2.1. Reagents. MWNTs (95%; length 10 𝜇m) were obtainedfrom Hanwha Nanotech (South Korea). Cadmium sulfatehydrate (CdSO

4⋅(3/8)H

2O)was obtained from Junsei Chemi-

cal (SouthKorea), and seleniumpowder (Se powder), sodiumnitrite (NaNO

2), 4-aminothiophenol (4-ATP), sodium boro-

hydride (NaBH4), D-(+)-glucose, and glucose oxidase (GOD,

17300 unit/g) were purchased from Sigma-Aldrich (USA).Phosphate buffer solution (PBS) was prepared by mixingstock solutions of NaH

2PO4and Na

2HPO4and then adjust-

ing to pH = 7.0. All solutions for the experiments were pre-pared with water purified in a Milli-Q plus water purificationsystem (Millipore, USA). Glassy carbon electrodes (GCEs)were purchased from Bioanalytical Systems (USA) (modelMF-2012).

2.2. Preparation of Biosensor Based on TGA-Capped CdSeQDs for Detecting Glucose. The fabrication procedure of theglucose oxidase- (GOD-) immobilized biosensor based onTGA-capped CdSe QDs is exhibited in Scheme 1. The GCEwas modified by the following steps. Prior to modification,the surface of the GCE was cleaned by polishing with 0.3𝜇m𝛼-Al2O3powder and then rinsed with distilled water and

cleaned ultrasonically in acetonitrile for 3min. MWNT wasultrasonicated at room temperature in a 3 : 1 mixture ofsulfuric acid and nitric acid. The obtained MWNT wasdispersed in a nafion solution, which was a mixture of 1.0mLmethanol and 40 𝜇L nafion, to give an MWNT suspension.Then a 20𝜇LMWNT suspensionwas dropped onto a cleanedGCE (MWNT/GCE). Meanwhile, 0.07 g 4-aminothiophenol

(4-ATP) and 0.2 g sodium nitride (NaNO2) were dissolved

in 40mL distilled water at 0∼5∘C. After the two reagentswere mixed, 6.0M cooled hydrochloride solution was slowlyadded to the mixture solution. After vigorous stirring, abright yellow 4-aminothiophenol diazonium salt solutionwas obtained. The synthesized 4-aminothiophenol diazo-nium salts were deposited electrochemically on the surface oftheMWNT/GCE electrode at constant potential of−0.7 V for1200 s (named as SH/MWNT/GCE). To immobilize theTGA-capped CdSe QDs onto the surface of the SH/MWNT/GCEby self-assembly, the SH/MWNT/GCE was immersed for10∼15 h in 5mL synthesized TGA-capped CdSe QD suspen-sion (CdSe/SH/MWNT/GCE). Finally, 2.0 𝜇L glucose oxidase(GOD, 3.0mg/mL) was dropped on the surface of theCdSe/SH/MWNT/GCE to fabricate an ECL biosensor basedon TGA-capped CdSe QDs for clinical diagnosis with adiabetic.

2.3. Preparation of TGA-Capped CdSe QDs. The preparationprocedure of the thioglycolic acid- (TGA-) capped CdSe QDsusing reduction reagents is shown in Scheme 2. Se powder(0.02 g) and NaBH

4(0.10 g) in ethanol (15.0mL) were added

in the left side round flask and stirred until dissolved. Inthe other round flask, CdCl

2(0.01 g) and TGA (0.01 g) with

NaOH in 50mL water were dissolved at 90∘C. Next 0.1MH2SO4was dropped in the left side round flask using a drop-

ping funnel in order to prepare H2Se gas. The preparation

mechanism of the TGA-capped CdSe QDs is also shown inScheme 2. The result was that we could obtain TGA-cappedCdSe QDs of various sizes by controlling the reaction time.

2.4. Instrumentation. Cyclic voltammetry (CV) was per-formed using a potentiostat/galvanostat model 283 (AmetekPAR, USA) and a conventional three-electrode system com-prising a composite-coated glassy carbon (diameter 2mm)working electrode, a platinum wire counterelectrode, and anAg/AgCl (saturated KCl) reference electrode. Electrochemi-cal signals were recorded using an H7468-01 photomultipliertube (PMT) system (Hamamatsu Photonics, Japan). The

Journal of Nanomaterials 3

TGA-capped CdSe QDs

H2SO4

N2H2Se

Ethanol solution (Se) TGA-capped metal ions in H2O

NaBH4 + Se + 3C2H5OH NaHSe + B(OC2H5)3 + 3H2

NaHSe + H2SO4 H2Se(g) + NaHSO4

2HSCH2COOH(TGA) + NaOH + CdCl2 HSCH2COO−Cd2+

H2Se(g) + HSCH2COO−Cd2+ CdSe

Scheme 2: Preparation procedure of the thioglycolic acid- (TGA-) capped CdSe QDs using reduction reagents.

entire ECL cell was enclosed in a light-proof dark box. ECLmeasurements were carried out in 0.1M PBS (pH 7). Theapplied working potential ranged from 0 to −2.0V and thecycle scan rate was 100mV/s. A high voltage power supplyof 750V was applied to the PMT and all experiments wereperformed 10 times.

3. Results and Discussion

3.1. Synthesis and Characterization of TGA-Capped CdSeQDs.Quantum dots are widely used not only in the photoelec-trochemical field but also in biosensors, biological imaging,and bioconjugates because of their remarkable electronic andoptic properties. First, TGA-capped CdSe QDs were easilysynthesized using reducing agents. The morphology andparticle size of the TGA-capped CdSe are shown in Figure 1.Overall, the TGA-capped CdSe QDs were spherical particleswith an aggregation of small particles of 3∼5 nm size.TheUV-vis spectrum, photoluminescence (PL) spectrum, and DLSdata of TGA-capped CdSe QDs are shown in Figure 2. Theabsorbance spectrum displays an excitation peak at 428 nm.The luminescence spectra at 610 nm are confirmed. In theUVspectrum, the band gap and the size of the TGA-capped CdSeQDs were calculated as 2.24 eV and 10.8 nm, respectively, asfollows:

Band gap (eV) = 1240/𝑥 (2.24 eV) ,

Size (nm) = (−6.6521 × 10−8) 𝜆uv3

+ (1.9557 × 10−4) 𝜆uv2

− (9.2352 × 10−2) 𝜆uv

+ 13.29 (10.8 nm) .

(1)

In the DLS data, the size of the TGA-capped CdSe QDswas 84 nm because of the aggregation of small QDs of 6 nmwith each other. The results showed that the TGA-capped

CdSe QDs in aqueous solution were aggregated at roomtemperature.

3.2. Fabrication and Characterization of a GOD-ImmobilizedBiosensor Based on CdSe QDs. In our previous study, a con-jugated phenylene polymer with carboxylic acid was graftedonto the MWNT surface of an electrode by electrochemicalpolymerization. Here, the conjugated phenylene polymer-graftedMWNT can be also used as electron transfer supportson electrodes. Furthermore, the thiol group placed on thesupports of the electrode can serve as a binding site forcovalent attachment to crystal metal nanoparticles. The SEMsurface images during the preparation process of the GOD-immobilized biosensor are displayed in Figure 3, where (a)is GCE surface, (b) is surface image of the MWNT/GCEelectrode, (c) is the surface image of the SH/MWNT/GCE,(d) is the surface image of the CdSe/SH/MWNT/GCE, and(e) is the GOD-immobilized biosensor, namely, GOD/CdSe/SH/MWNT/GCE. After modification using MWNT suspen-sion, the surface of the GCE appears as a crystal-like form(b), while the surface of the TH/MWNT/GCE (c), whichmeans the conjugated phenylene polymer-grafted MWNT/GCE, shows a smooth form because of the formation ofgrafted polymer on the MWNT/GCE electrode. As a resultof this step, there were no significant changes in terms of theimmobilization of the CdSe QDs onto the surface of the SH/MWNT/GCE because of differences in nanosize; however,therewas a significant change inmorphology to a crystal solidform after the immobilization of theGODas enzyme onto theCdSe/SH/MWNT/GCE (Figure 3(e)) because of the dry stateGOD.The results confirmed that the GOD-immobilized ECLbiosensor based onCdSeQDs had been prepared successfullyfor the detection of glucose.

The contact angle images of bare GCE (a), MWNT/GCE(b), SH/MWNT/GCE (c), CdSe/SH/MWNT/GCE (d), andGOD/CdSe/SH/MWNT/GCE (e) are shown in Figure 4.From an examination of the water contact angles (Figure 4),the value of the contact angle of the GCE was determinedto be 64.3∘ (Figure 4(a)) and that of the MWNT/GCE was


Figure 1: TEM images of the TGA-capped CdSe QDs.

350 400 450 500 550 600 650

0.00

0.05

0.10

0.15

0.20

0.25

Wavelength (nm)

Abso

rban

ce

−10000

0

10000

20000

30000

40000

50000

60000

70000

Inte

nsity

(a.u

.)

609.8nm

428nm

400 500 600−0.1

0.0

0.1

0.2

0.3

Wavelength (nm)

Abso

rban

ce

x

0 100 200 300 400 500 600

0

2

4

6

8

10

Mas

s (%

)

Diameter (nm)

84nm

6nm

Band gap (eV) = 1240/x (2.24 eV)

Size (nm) = (−6.6521 × 10−8) uv3+ (1.9557 × 10

−4uv2− (9.2352 × 10

−2uv + 13.29 (10.8nm)𝜆 ) uv𝜆 ) 𝜆

Figure 2: UV-visible, PL spectra, and DLS data of the TGA-capped CdSe QDs.


(a) (b)

(c) (d) (e)

Figure 3: SEM images of bare GCE (a), MWNT/GCE (b), SH/MWNT/GCE (c), CdSe/SH/MWNT/GCE (d), and GOD/CdSe/SH/MWNT/GCE (e).

64.27

(a)

64.2

(b)

71.5

(c)

35.4

(d)

49.5

(e)

Figure 4: Contact angle images of bare GCE (a), MWNT/GCE (b), SH/MWNT/GCE (c), CdSe/SH/MWNT/GCE (d), and GOD/CdSe/SH/MWNT/GCE (e).


Spectrum 1

2 4 6 8 10 12 14 16 18 20

COF

S

(keV)Full scale 145 cts cursor: 0.000

(a)

Spectrum 1

2 4 6 8 10 12 14 16 18 20

SeCOF

S

Cd

Se Se

(keV)Full scale 145 cts cursor: 0.000

(b)

Spectrum 1

2 4 6 8 10

(keV)12 14 16 18 20

Full scale 145 cts cursor: 0.000

SeCO

F

S

Cd

Se Se

(c)

Figure 5: EDS results of SH/MWNT/GCE (a), CdSe/SH/MWNT/GCE (b), and GOD/CdSe/SH/MWNT/GCE (c).

determined to be 64.2∘ (Figure 4(b)). After electrochem-ical reduction of 4-aminothiophenol on the surface of theGCE, the contact angle of the SH/MWNT/GCE increased to71.5∘ (Figure 4(c)), while the contact angle of the CdSe/SH/MWNT/GCE decreased to 49.5∘ (Figure 4(d)) owing toimmobilization of CdSe QDs onto the electrode. This resultmeans that the GCE was modified successfully by elec-trochemical reduction and immobilization of CdSe QDs;moreover, hydrophilicity was introduced to the surface. Inaddition, the immobilization ofGODon the electrode surfaceled to a slight decrease in the contact angle (Figure 4(e))because of increasing hydrophilicity. From these results, wecould confirm that the GOD-immobilized biosensor wassuccessfully fabricated.

Relatively dense decoration of the CdSe QDs on theelectrode was observed in the GOD-immobilized biosensor.Energy dispersive X-ray (EDX) analysis (Figure 5) confirmedthat Cd and Se were present in the GOD-immobilizedbiosensor. The calculated atomic ratios of Cd to Se wereshown to be close to 1 : 1 (Figures 5(b) and 5(c)), which is ingood agreement with the stoichiometric ratio of CdSe. Theseresults confirm that the GOD-biosensor based on CdSe QDswas successfully prepared with phenylene polymer-graftedMWNT.

In order to confirm the introduction of the thiol groupand CdSe QDs after immobilization of QDs and electro-chemical reduction of 4-aminothiophenol diazonium salt,a surface analysis was performed (Figure 6) to providehigh resolution XPS spectra of S2p, Cd3d, and Se3d onthe SH/MWNT/GCE (a), CdSe/SH/MWNT/GCE (b), and

GOD/CdSe/SH/MWNT/GCE (c). The doublet XPS spec-trum of S2p on the SH/MWNT/GCE at 163.9 eV and 169.7 eV(Figure 6(a)) was confirmed, which is indicative for thesignal of S in 4-thiophenyl groups, while the unknown peakoriginated from a disulfide or sulfide bond of conjugatedaromatic polymer on the modified carbon electrode. Afterimmobilization of the CdSe QDs, the doublet Cd3d peaksat 406 eV and 414 eV and Se3d at 55 eV appeared for theCdSe/SH/MWNT/GCE and GOD/CdSe/SH/MWNT/GCE,respectively. Also there was a decrease in the intensity of theCd3d and Se3d peaks after immobilization of GOD onto theCdSe/SH/MWNT/GCE. From these results, we confirmedthat the GOD-immobilized biosensor was successfully pre-pared for detection of glucose.

3.3. Characterization of an ECL Biosensor Based on CdSe QDsfor the Detection of Glucose. Cyclic voltammetry and ECLintensity measurements of the fabricated ECL biosensor werecarried out in 0.1M PBS (pH = 7.0) at 100mVs−1 to show theproduct mechanism of H

2O2from glucose by GOD and the

ECL signal mechanism of the ECL biosensor based on CdSeQDs (Figure 7).

The electrochemical behavior of the fabricated ECLbiosensor (GOD/CdSe/SH/MWNT/GCE) was confirmed asa function of glucose concentration under optimized exper-imental conditions (Figure 8). The redox peaks of H

2O2

(below 10−3M) could not be obtained (Figure 8(a)): however,the ECL signals were obtained to show a similar pattern (Fig-ure 8(b)) without any change of glucose concentration. Withan increasing concentration of glucose (Figure 8(c)), there


160 165 170 17514001600180020002200240026002800

Binding energy (eV)

Inte

nsity

S2p

(a)

Binding energy (eV)

Inte

nsity

155 160 165 170 1752500300035004000450050005500

S2p

(b)

Binding energy (eV)

Inte

nsity

155 160 165 170 17522002400260028003000320034003600380040004200

S2p

(c)

(b)

405 410 415 4209000

1000011000120001300014000 Cd3d

Binding energy (eV)

Inte

nsity

(c)

405 410 415 420850090009500

1000010500110001150012000

Cd3d

Binding energy (eV)

Inte

nsity

(b)

45 50 55 60 6519002000210022002300240025002600 Se3d

Binding energy (eV)

Inte

nsity

(c)

45 50 55 6017001800190020002100220023002400 Se3d

Binding energy (eV)

Inte

nsity

Figure 6: High resolution XPS spectra of S2p, Cd3d, and Se3d to SH/MWNT/GCE (a), CdSe/SH/MWNT/GCE (b), and GOD/CdSe/SH/MWNT/GCE (c).

Glucose + O2GOD gluconic acid + H2O2

CdSe + ̇OH + OH− CdSe+ + 2OH−

CdSe(e−)

e−CdSe

Electrode

CdSe(e−)

CdSe∗

hv

CdSe

H2N

H2N

O

O

OH

OH

S

S

S

S

S

O

O

O

HO

HO

HO

NH2

NH2

NH2

∗= excited state

Figure 7: ECL mechanism of TGA-capped CdSe QDs.

was an increase in the concentration of H2O2as a decom-

position product coming from the chemical reaction betweenglucose and theGOD enzyme. For this reason, the ECL signalis increased because the intensity of the ECL signal is affecteddirectly by the concentration of H

2O2. The concentration

of glucose enhanced the intensity of the ECL signal of the

fabricated ECL biosensor based on CdSe QDs in 0.1M pH7.0 (see Figure 8). The calibration curve for glucose wasconstructed using a current ECL biosensor based on CdSeQDs. The signal intensity was linearly proportional to theconcentration of glucose between 1.0 × 10−3 and 1.6 × 10−14M(Figure 8(d)).


−2.0 −1.5 −1.0 −0.5 0.0

−6.0

−4.0

−2.0

0.0

2.0

V/V (vs Ag/AgCl)

I (m

A)

×10−5

(a)

500 1000 15000

100

200

300

400

500

600

Time (s)

Inte

nsity

(a.u

.)

High intensity

(b)

612 614 616 618 620

0

50

100

150

200

250

300

Time (s)

Inte

nsity

(a.u

.)

10−3 M

10−4 M

10−5 M

10−6 M

10−7 M

10−8 M

10−9 M

10−10 M

10−11 M

10−12 M

10−13 M

10−14 M

(c)

6160

50

100

150

200

250

Time (s)

Inte

nsity

(a.u

.)

10−3 M

10−4 M

10−5 M

10−6 M

10−7 M

10−8 M

10−9 M

10−10 M

10−11 M

10−12 M

10−13 M

10−14 M

(d)

Figure 8: Cyclic voltammogram (a) ECL intensity of 10−13M glucose (b) and intensity according to glucose concentration (c and d) in 0.1MPBS (pH = 7.0) GOD-immobilized biosensor with a scan rate 100mV/s.

4. Conclusion

A rapid and sensitive ECL biosensor based on CdSe QDswas developed for the determination of glucose. The CdSeQDs were synthesized using TGA, and their morphologyand electrochemical properties were confirmed by TEM,UV-vis spectrum, and PL analysis. Also, conjugated pheny-lene polymer was formed easily on the surface of theelectrode by an electrochemical method, which was usedfor the immobilization of CdSe QDs and enzymes. In thisluminescence mechanism, the ECL-potential signal of CdSeQDs resulted from the formation of H

2O2, which arises

from a chemical reaction between glucose and glucose oxi-dase (GOD). These results could be applied to the clinical

diagnosis of diabetes. Fabricated ECL biosensors based onCdSeQDs have great potential to provide rapid, sensitive, andcost-effective approaches for the clinical diagnosis of diabe-tes.

Competing Interests

The authors declare that they have no competing interests.

Acknowledgments

This work was partly supported by the National ResearchFoundation of Korea Grant, funded by the Korean Govern-ment (NRF-2015N043).


References

[1] P. Bertoncello and R. J. Forster, “Nanostructured materialsfor electrochemiluminescence (ECL)-based detectionmethods:recent advances and future perspectives,” Biosensors and Bio-electronics, vol. 24, no. 11, pp. 3191–3200, 2009.

[2] H.Dai, G. Xu, S. Zhang et al., “Carbonnanotubes functionalizedelectrospun nanofibers formed 3D electrode enables highlystrong ECL of peroxydisulfate and its application in immunoas-say,” Biosensors and Bioelectronics, vol. 61, pp. 575–578, 2014.

[3] J. H. Sloan, R. W. Siegel, Y. T. Ivanova-Cox, D. E. Watson,M. A. Deeg, and R. J. Konrad, “A novel high-sensitivity elec-trochemiluminescence (ECL) sandwich immunoassay for thespecific quantitative measurement of plasma glucagon,”ClinicalBiochemistry, vol. 45, no. 18, pp. 1640–1644, 2012.

[4] S. Deng, J. Lei, Y. Huang, Y. Cheng, and H. Ju, “Electrochemilu-minescent quenching of quantum dots for ultrasensitive immu-noassay through oxygen reduction catalyzed by nitrogen-dopedgraphene-supported hemin,” Analytical Chemistry, vol. 85, no.11, pp. 5390–5396, 2013.

[5] A. I. Vinik andC.Chaya, “Clinical presentation and diagnosis ofneuroendocrine tumors,”Hematology/Oncology Clinics of NorthAmerica, vol. 30, no. 1, pp. 21–48, 2016.

[6] T. Wang, S. Zhang, C. Mao et al., “Enhanced electrochemilu-minescence of CdSe quantum dots composited with grapheneoxide and chitosan for sensitive sensor,” Biosensors and Bioelec-tronics, vol. 31, no. 1, pp. 369–375, 2012.

[7] C. S. Robb, “The analysis of abrin in food and beverages,”TrAC—Trends in Analytical Chemistry, vol. 67, pp. 100–106,2015.

[8] X. Yu, Y. Chai, J. Jiang, and H. Cui, “Sensitive ECL sensor forsequence-specific DNA fromMycobacterium tuberculosis basedon N-(aminobutyl)-N-ethylisoluminol functionalized goldnanoparticles labeling,” Journal of Photochemistry andPhotobio-logy A: Chemistry, vol. 241, pp. 45–51, 2012.

[9] B.-J. Hwang, J. Jin, R. Gunther et al., “Association of the Rad9-Rad1-Hus1 checkpoint clamp with MYH DNA glycosylase andDNA,” DNA Repair, vol. 31, pp. 80–90, 2015.

[10] Y.-P. Dong, Y. Zhou, J. Wang, and J.-J. Zhu, “Electrogeneratedchemiluminescence resonance energy transfer between luci-genin and CdSe quantum dots in the presence of bromide andits sensing application,” Sensors and Actuators B: Chemical, vol.226, pp. 444–449, 2016.

[11] M. Yang, Y. Wang, and H. Wang, “𝛽-cyclodextrin functional-ized CdTe quantum dots for electrochemiluminescent detec-tion of benzo[a]pyrene,” Electrochimica Acta, vol. 169, pp. 7–12,2015.

[12] H. Chen, W. Li, P. Zhao, Z. Nie, and S. Yao, “A CdTe/CdSquantumdots amplified graphene quantumdots anodic electro-chemiluminescence platform and the application for ascorbicacid detection in fruits,” Electrochimica Acta, vol. 178, pp. 407–413, 2015.

[13] Y. P. Dong, Y. Zhou, J. Wang, Y. Q. Dong, and C. M. Wang,“Electrogenerated chemiluminescence of quantum dots withlucigenin as coreactant for sensitive detection of catechol,”Talanta, vol. 146, pp. 266–271, 2016.

[14] T. Zhang,H. Zhao,G. Fan, Y. Li, L. Li, andX.Quan, “Electrolyticexfoliation synthesis of boron doped graphene quantum dots: anew luminescent material for electrochemiluminescence detec-tion of oncogene microRNA-20a,” Electrochimica Acta, vol. 190,pp. 1150–1158, 2016.

[15] J.-S. Park, Y. O. Kang, S.-R. Lee, H. Bae, S. Choi, and S.-H.Choi, “Fabrication of an electrogenerated chemiluminescencebiosensor based on CdSe quantum dots for the determinationof Acetylcholine,” Sensor Letters, vol. 13, no. 1, pp. 85–91, 2015.

Submit your manuscripts athttp://www.hindawi.com

ScientificaHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation http://www.hindawi.com Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation http://www.hindawi.com Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials

Research Article Electrochemiluminescence Biosensor Based...

Documents

Transcript of Research Article Electrochemiluminescence Biosensor Based...