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Sensors and Actuators B 177 (2013) 555– 561

Contents lists available at SciVerse ScienceDirect

Sensors and Actuators B: Chemical

journa l h o mepage: www.elsev ier .com/ locate /snb

elf-made non-enzymatic silver electrode from recordable CDs for fast detectionf glucose in blood

uxing Chena, Lin Liua, Meirong Wanga, Chengyin Wanga,∗, Xiaoya Hua, Guoxiu Wangb

College of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Environmental Engineering and Monitoring, Yangzhou University, 180 Si-Wang-Ting Road,angzhou 225002, ChinaDepartment of Chemistry and Forensic Science, University of Technology, Sydney, City Campus, Broadway, Sydney, NSW 2007, Australia

r t i c l e i n f o

rticle history:eceived 11 August 2012eceived in revised form8 November 2012ccepted 19 November 2012vailable online 29 November 2012

a b s t r a c t

An electrochemical sensor based on a self-made electrode from recordable CDs was developed for thenon-enzymatic detection of glucose by chronoamperometry. We discussed the amperometric currentresponse of glucose with the change of potential, pH and electrode area, and determined the optimumdetection conditions. The current response measurements were performed in a phosphate buffered solu-tion (pH 6.5) with a potential of −0.50 V, and presented a linearity over the range of 0.5–13 mmol/L(r = 0.996). The experimental results of the designed sensor demonstrate that this method has merits

eywords:ecordable CDson-enzymatic sensorhronoamperometry

such as simple operation, low cost and rapid responses. The results of detecting glucose in blood sampleswere satisfactory.

© 2012 Elsevier B.V. All rights reserved.

lucoselood

. Introduction

Glucose detection is extremely important in the diagnoses andreatment of diabetes patients. Diabetes is a disease resulting fromyperglycemia and insulin deficiency, and leads to complicationsuch as renal, retinal, cardiac and neural pathema [1]. The compli-ations can be reduced through strictly controlled personal bloodlucose [2]. Increasingly, more diabetic patients have to measureheir blood glucose levels regularly each day. Therefore, a fast andeliable method of monitoring the blood glucose level is needed [3].ecently, many techniques have been undertaken for the determi-ation of blood glucose. For example, Ayupe de Oliveira et al. [4]eveloped a spectrophotometric method for the determination oflood glucose, and used an on-line tubular reactor with glucosexidase immobilized on resin. Der and Dattelbaum [5] constructed

fluorescent glucose/galactose binding protein (GGBP) biosensor,sed to set up double-cysteine mutations that allowed the selec-ive covalent attachment of thiol-reactive dyes. Pleitez et al. [6]stablished a new infrared spectroscopic analysis approach to non-nvasive glucose measurement. However, there has been more

ocus on electrochemical methods of glucose detection in recentears because of numerous advantages, such as simple and rapidperation, high sensitivity and low detection limits.

∗ Corresponding author. Tel.: +86 514 87888454; fax: +86 514 87975244.E-mail addresses: wangcy@yzu.edu.cn, yzswcy@yzcn.net (C. Wang).

925-4005/$ – see front matter © 2012 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.snb.2012.11.061

Electrochemical glucose sensors began with glucose enzymeelectrodes, which were quickly developed. The sensors are basedon the enzyme glucose oxidase (GOx); and the GOx worksthrough redox reactions with glucose. During the interaction,hydrogen peroxide is generated, which is formed as a redoxmediator, and produces the redox signal. Many glucose biosen-sors are dependent on the electrochemical oxidation of hydrogenperoxide, and can be detected through oxidation at high poten-tials. Zhou et al. [7] proposed a new glucose sensor, containingm-phenylenediamine and glucose oxidase (GOx), by the elec-tropolymerization of m-phenylenediamine in the phosphate buffersolution. Liu [8] fabricated an enzyme electrode, based on a self-assembled Prussian Blue (PB) and glucose oxidase (GOD) modifiedelectrode. However, there may be interferences from commoninterfering species, such as ascorbic acid (AA) and uric acid (UA),which cause serious difficulties for the determination of glucose[9]. In addition, the catalytic activity of GOx is impacted by environ-mental conditions such as temperature, humidity, pH value, organicreagents, and oxygen restriction, which would affect the sensitivityand specificity [10]. Furthermore, GOx is relatively expensive. Thedisadvantages limit the widespread use of the enzyme-modifiedelectrodes. Therefore, the development of non-enzymatic glucosesensors is necessary.

Non-enzymatic amperometric sensors for direct determinationof glucose has attracted great interest from researchers in recentyears, and many enzymeless glucose sensors have been developedwith noble metal nanoparticles (Pt, Au and Pd) [11,12], metal oxides

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and reference electrodes covered onto a PVC substrate. For counterand reference electrode, the metallic layer was printed using theplatinum and Ag/AgCl inks. For working electrode, a sheet of Agfilm (3 mm × 3 mm) was adhered to the working electrode site

56 Y. Chen et al. / Sensors and A

CuO, Co3O4, NiO, etc.) [13–15], metal alloys (Pt–Pb, Pt–Ru, Pt–Au,i–Pd, etc.) [16–18], and nano-composites [19,20]. These non-nzymatic glucose sensors have been reported to have remarkableualities, such as lower cost, faster response time, stability and the

ndependence of oxygen. But there is no report on glucose detectionirectly with Ag-NPs modified electrodes.

Compact discs (CDs) are a form of optical data storage contain-ng a nanometric metal layer such as gold, silver or aluminum. The

etal layers from CDs as electrodes can be called CDtrodes. TheDtrodes have many advantages, such as low-cost, easy handling,nd disposable surface. Because of the many benefits, CDtrodesave been applied to electrochemical and biochemical analysis.

variety of literature is reported to show the applications ofDtrodes. Banuls et al. [21] demonstrated several approaches tohe covalent modification of CDs and applied them to DNA probemmobilization, hybridization, and SNP (single nucleotide poly-

orphisms) discrimination assays on polycarbonate disc surfaces.orais et al. [22] performed high-density competitive indirecticroimmunoassays based on a low-reflectivity compact disc as

nalytical platform. Challener et al. [23] designed a surface plas-on resonance (SPR) gas sensor using a rotating optical disc to

etect ammonia, which can easily be extended to multiple channelsnd is inexpensive. Tamarit-López et al. [24] presented an analyt-cal potential for polystyrene (PS) spin-coated modified compactisc (CD) surfaces as platforms for the development of microar-ay immunoassays. Alexandre et al. [25] proposed a compact discs a support for constructing DNA microarrays suited to genomicnalysis.

In this paper, we developed a non-enzymatic glucose sensor forDs by coating a reflective metal layer with silver, which performedith the same advantages of metal nanoparticles modified elec-

rodes. The extreme significance of this work is the recycling ofecordable CDs, as well as the simple and easy preparation of theDtrodes. What is important is that the low cost of CDtrodes andhe electrode area can be easily modified according to the needs ofhe experiments. The response of the proposed electrode to glucoseoncentrations was linear over the range of 0.5–13 mmol/L. TheDtrode can be used to determine the blood glucose directly, andhe interference of ascorbic acid (AA) and uric acid (UA) are effec-ively avoided. Here we provide a possible method for the detectionf glucose in human blood.

. Experimental

.1. Reagent

Concentrated nitric acid, uric acid, and sodium dihydrogenhosphates were purchased from Sinopharm Chemical Reagento. Ltd. (Shanghai, China). Ascorbic acid and uric acid were pur-hased from Guangzhou Chemical Reagent Company (Guangzhou,hina). The phosphate buffer solutions (PBS) (0.1 mol/L) were pre-ared from NaH2PO4 and Na2HPO4. All the other chemicals were ofnalytical reagent grade, and used without further purification. Allater used for preparing the solutions in this work was re-distilled.

.2. Apparatus

Electrochemical experiments were performed with a CHI 1232lectrochemical workstation (Chenhua Instruments Company,hanghai, China) with a conventional three-electrode system. Theelf-made CD silver electrodes, an Ag/AgCl and a platinum electrode

ere used as the working electrode, reference and the auxil-

ary electrode, respectively. Scanning Electron Microscope (SEM)easurements were conducted on an S-4800|| FESEM (Hitachiigh-Technologies Corporation, Japan) at an accelerating voltage of

ors B 177 (2013) 555– 561

20 kV. 85-1 magnetic stirrers (KeEr Instruments Company, Nanjing,China) and a Mettler-Toledo FE20 pH meter (Shanghai, China) wereadopted. All experiments were carried out at room temperature(25 ◦C).

2.3. Composition of recordable compact disc and preparation ofthe CD electrode

Recordable CDs used in this work were obtained from RITEK Cor-poration (CD-R 52X, 5.25 in.). This kind of CD contains four parts:(a) a polycarbonate of high durability provides the mechanical sup-port to the unit and offers protection for the discs [26,27]. (b) On theabove-mentioned layer, a thin layer of photosensitive organic dyeis deposited, which can be constituted with azogroups, phthalocya-nine, or metal-stabilized cyanine [28]. (c) Over the second layer, therecording progress was performed by use of a reflective metal layerof between 50 and 100 nm. This layer usually is made of gold, silver,or aluminum [29], but in recent years more CDs have silver or goldinstead of aluminum as the reflective layer, with silver reflectorsshowing better performance. (d) This metal layer is covered againwith two polymeric protecting films: one film is a lacquer that pro-tects the reflective film and the other accepts the ink from printers[30].

The compact disc was divided into many parts, and each partoffered several electrodes. To obtain the thin reflective layerdemanded, a pair of scissors was employed. The CDs were cutinto 10–16 slices, like a pizza. To construct the CD electrodes,it was necessary to remove the protective film from its surface.Some researchers reported the process to expose the reflectivelayer after a chemical attack to protecting films [26,28]. In ourexperiment, the thin metal film with irregular shape was easilypeeled off with a knife and tweezers. Subsequently, the Ag filmwas cut into strips with widths of 0.5 cm and lengths of 2.0 cmin order to be convenient on next cleaning step. The film stripswere washed with absolute alcohol to remove organics. Andthen, 3 mm × 3 mm Ag film was tailored from the strip as theworking electrode according to our electrochemical cell designed(Fig. 1(A)). We referred to a screen printed structure based on the3-electrode electrochemical cell to propose our sensor, but theregular working electrode was replaced by Ag film from CD-R.Details of its fabrication are provided as below: working, counter

Fig. 1. Images of the portable glucose sensor (A) and the portable glucose sensorconnected to the USB port (B). (a) the self-made silver CDs electrode, (b) a platinumelectrode, (c) Ag/AgCl electrode, (d) an insulating coat, (e) PVC substrate.

ctuators B 177 (2013) 555– 561 557

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ith a kind of conducting glue. Then an insulator layer was placedver the conducting paths (1 mm width). The proposed sensor is

portable glucose sensor, which is like a USB flash with a USBort to connect to an electrochemical workstation, as shown inig. 1(B). This device was applied directly to detect blood glucose.his strategy will probably be commercialized in the future.

.4. Electrochemical test

The electrochemical characterization of the CDtrode was evalu-ted by using cyclic voltammetry (CV) in 0.1 mol/L PBS. The currentesponse measurements were performed in a phosphate bufferedolution (pH 6.5, C = 0.1 mol/L) with a potential of −0.50 V, and theetection of glucose concentration in human blood was performednder the same conditions.

. Results and discussion

.1. Characterization of the CD electrode

A representative SEM image of a CDtrode, as shown in Fig. 2,learly indicates nanoparticles uniformly attached to the electrodeurface, with an average diameter of about 20 nm. The Energy Dis-ersive X-ray spectroscopy (EDX) date image of the CDtrode in Fig. 3hows that the substance in the film was Ag nanoparticles. Whenhis film was used as an electrode material, the CDtrode became ang nanoparticles electrode.

To characterize the electrochemical behavior of the self-madeDtrode, a cyclic voltammogram (CV) of the CDtrode (Fig. 4(A)) in.1 mol/L H2SO4 solution was compared with one of a commercialilver electrode (Fig. 4(B)). The two peaks, one anodic (situated near

Fig. 3. The EDX resu

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ig. 4. The cyclic voltammograms of a CDtrode (A) and a commercial electrode (B) recordate of 50 mV/s.

Fig. 2. SEM image of CDtrode.

to 0.60 V) and the other cathodic (at 0.30 V), were observed. BothCVs presented practically the same shape, which indicated that theself-made CDtrode had the same properties as a commercial silverelectrode.

3.2. Voltammetric response to glucose

Voltammetric responses to different glucose levels wererecorded with scan rate of 50 mV/s and potential range from −0.7 Vto 0 V in Fig. 5. The experimental result indicated that the cur-rent response increased with increasing glucose concentration.

lts of CDtrode.

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

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ed in 0.1 mol/L H2SO4 by sweeping the potential between −0.4 V and 1.3 V at a scan

558 Y. Chen et al. / Sensors and Actuators B 177 (2013) 555– 561

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but stability of the current became worse and noise increased. Thus,the area should be controlled within as small a space as possible.We chose 3 mm × 3 mm of CDtrode area in our experiment.

4

6

8

10

12

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16

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ig. 5. The cyclic voltammograms of the CDtrode in 0.1 mol/L PBS containing glu-ose with scan rate of 50 mV/s and potential range from −0.7 V to 0 V. (a) Blank, (b).1 mmol/L glucose, (c) 0.5 mmol/L glucose, and (d) 3 mmol/L glucose.

he AgNPs electrode gives the high catalytic activity toward glu-ose oxidation in a neutral phosphate buffer provides a tentativelectrode reaction for the oxidation of glucose at −0.5 V. Theoltammetric response on glucose concentration in neutral andlkaline medium might be due to the glucose oxidation on the influxf OH− [17]. In the presence of glucose, glucose molecules werelectro-absorbed on the surface of the CDtrode, forming a layerf glucose intermediates. With the potential scanning to −0.5 V,he adsorbed glucose intermediates were oxidized on the electrodeurface, causing the increase of the current [18]. Referring to a liter-ture [31] a tentative electrode reaction for the oxidation of glucoseas shown in Scheme 1. It has been reasoned that the weakly boundydrogen atom at the carbon C atom is the first to be detached fromhe glucose molecule at the electrode poised at low potentials.

.3. Effect of the potential on the response current

Potential controllability is one of the key parameters inhronoamperometry. Fig. 6 shows the potential effect of the oper-tion on the amperometric response to detect 4.0 mmol/L glucose.n the CDtrode surface, glucose oxidation exhibited strong elec-

rocatalytic activity at a negative potential of −0.50 V. Accordingo Guo et al. [18], this is probably because glucose molecules weredsorbed onto the CDtrode surface and formed a layer of glucosentermediates. The intermediates could be oxidized on the CDtrodeurface when the potential was −0.50 V, resulting in the increasef the current. The response current decreased when the potentialas further moved from −0.50 V. The glucose intermediates were

xidized with difficultly at a more negative potential, and Ag-NPsould be oxidized with the increase of potential. So the potential of0.50 V was chosen as the optimum potential in our experiments.uo et al. proposed a Pt–Pb nanostructures modified electrode toetect glucose at a negative potential of −0.1 V, the interference

f ascorbic acid and uric acid effectively was avoided at a negativeotential [18]. Huang and Zhu reported that the graphene and Au-Ps modified electrode exhibited good amperometric response tolucose at −0.2 V, with good reproducibility [32].

O

R

C OH

H

Ag

Adsorption

O

R

C OH

X

+ H+ + e-

Scheme 1. Electrochemical reaction on the CDtrode.

Fig. 6. Effect of the potential on the CDtrode response. Steady-state currents weremeasured in 0.1 mol/L phosphate buffer (pH 7.0) containing glucose 4.0 mmol/L.

3.4. Effect of the value of pH on the response current

Fig. 7 shows the effect of pH values on the response currentwhen pH values varied from 5.0 to 9.0 in the solution containing4.0 mmol/L glucose. With the increase of pH, the response currentsof the glucose on the CDtrode were increased, and reached the max-imum value at pH 6.5. While in base solutions, OH− would enhanceAg oxidation, and the CDtrodes were damaged. Therefore, the pHvalue of 6.5 was chosen to detect glucose, which is much closer tophysical conditions in human blood.

3.5. Effect of the CDtrode area on the response current

It is known that the electrode area strongly affects the responsecurrent. In order to get the stable current response, different elec-trode areas were chosen for the detection of glucose. The increase ofelectrode area could generate the increase of the current response,

5 6 7 8 9-4

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2

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Fig. 7. Effect of the pH on the CDtrode response. Steady-state currents were mea-sured at −0.50 V in 0.1 mol/L phosphate buffer containing glucose 4.0 mmol/L.

Y. Chen et al. / Sensors and Actuators B 177 (2013) 555– 561 559

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the same electrode area and in optimum conditions, was estimatedin 0.1 mol/L PBS (pH 6.5) at −0.50 V by the response to 1 mmol/L glu-cose, and yielded a mean current response of 11.1 �A mM−1 cm−2

with a relative standard deviation (RSD) of 3.7%. The repeatability

2.2

2.4

GlucoseGlucose AA UA

ig. 8. (A) The amperometric response of CDtrode for the successive addition of 0.5rea was 3 mm × 3 mm. (B) The corresponding calibration curve for glucose.

.6. Amperometric detection of glucose by the CDtrode

The amperometric response measurements of CDtrode wereerformed for the successive addition of 0.50 mmol/L glucose in.1 mol/L PBS (pH 6.5) at −0.50 V under gentle stirring. Fig. 8(A)hows a typical current–time plot for the CDtrode electrode upononsecutive additions of glucose. The response current increasedith successive additions of glucose. The inset plot displays the

esponse currents reaching a steady-state current signal within 1 s,ndicating a fast response of the sensor. The response time was

uch shorter than other reported glucose sensors [33–37], as sum-arized in Table 1. Fig. 8(B) displays the corresponding calibration

urve for glucose. The linear response range of the biosensor tolucose was from 0.5 mmol/L to 13 mmol/L and the correspondinginearity (R) is 0.996. The detection limit is 0.035 mmol/L. The limitf determination is lower than 1.0 mmol/L, which is the regularhose of commercialized glucometer sensors [38].

.7. Anti-interferent ability, repeatability, reproducibility andtability of the CDtrode

Over the last decades, a number of studies have been conductedo alleviate the drawbacks of enzymatic glucose sensors. The mostommon and serious problem is insufficient stability originatedrom the nature of the enzymes (either glucose oxidase (GOx) orlucose dehydrogenase (GDH)), which is hardly overcome [39]. Alltrips of glucometers in sold can be adversely affected by temper-ture, humidity and light. The strips should be consumed within

months from opening the packet. The glucose oxidase is inex-ensive but requires oxygen as a cosubstrate. Consequently, asxygen is depleted in the sample, performance decreases, whetherne is monitoring oxygen depletion, or hydrogen peroxide produc-

ion. A number of variables can influence the reliability of the testesults, including hematocrit, hypoxemia and hypotension. Thisensor avoided the independence of oxygen. Glucose dehydroge-ase is oxygen independent, and has the added attraction of being

able 1he response time compared with different glucose sensors.

Electrode modifier Response time (s) Reference

GOD/ZnO-NPs/GCE <4 Ali et al. [33]GOD/NLDH/CHT/GCE <5 Xu et al. [34]CoONRs/FTO 20–40 Kung et al. [35]Cu-NPs/ZnO/GCE <3 Kumar et al. [36]NiHCF/GCE <4 Wang et al. [37]The proposed CDtrode <1

ol/L glucose in 0.1 mol/L PBS (pH 6.5) at −0.50 V under gently stirring. The CDtrode

a well-established probe for monitoring biochemical reactions. Thedrawback is that the cofactors are relatively expensive and unsta-ble [40]. Also, the use of pyrroloquinoline quinone (PQQ) glucosedehydrogenase may be subjected to interference from a varietyof substances, namely maltose, icodextrin, galactose, xylose. [41].Ascorbic acid (AA) and uric acid (UA), which normally coexist withglucose in human blood, are well-known main interferents to theamperometric response of glucose. To evaluate the selectivity of theproposed biosensor, AA and UA were examined. Considering thatthe concentration of glucose in the healthy human blood is morethan 30 times that of AA and UA [42], 1 mmol/L glucose, 0.1 mmol/LAA and 0.1 mmol/L UA were added to 0.1 mmol/L PBS (pH 6.5) forthe amperometric response measurement of the CDtrode. In Fig. 9,the impact of UA and AA is nearly eliminated. This is because anegative potential can be avoided by the interference of AA andUA. Furthermore, some main coexist ions in human blood (Na+, K+,NH3

+, Ca2+, Fe2+, Cl−, PO43−), maltose, icodextrin, galactose, and

xylose were also been examined, and the effects could be ignored.The results indicated high selectivity of our CDtrode. Therefore, thesensor can be used for blood glucose detection effectively.

The response reproducibility of six CDtrodes, prepared under

0 100 200 300 400 500 600 700 8001.6

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Fig. 9. Current–time curve recorded at the glucose biosensor for addition of1 mmol/L glucose, 0.1 mmol/L ascorbic acid, and 0.1 mmol/L uric acid in 0.1 mol/LPBS (pH 6.5) at −0.50 V under gently stirring. The CDtrode area is 3 mm × 3 mm.

560 Y. Chen et al. / Sensors and Actuators B 177 (2013) 555– 561

Table 2The determination results of glucose in human blood samples.

Sample Glucose concentration (n = 6) (mM) Added (mM) Found (mM) RSD% (n = 6) Recovery%

1 4.263.00 2.87

3.295.7

4.00 3.89 97.25.00 4.91 98.2

2 3.173.00 3.03

3.9101.3

4.00 3.92 98.05.00 4.89 97.8

Table 3Comparison between the values obtained in the hospital and those obtained by using present sensor for the determination of glucose in human blood samples.

Sample number Determined in the hospital (mM) Determined by our biosensor (mM) Bias (mM)

1 4.46 4.72 +0.262 5.39 5.74 +0.353 5.73 5.55 −0.184 6.47 6.18 −0.29

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f the determination was investigated at −0.50 V and 25 ◦C in.10 mol/L PBS containing 1 mmol/L glucose, which yielded a rela-ive standard deviation of 4.8% for six continuous determinations ofhe same sample by using one proposed electrode. The results indi-ate that the CDtrode has good reproducibility and repeatability.hough manufacturers often provide meters at no cost to inducese of the profitable test strips, the consumer cost of each dispos-ble glucose strip ranged from about $0.35 to $1.00. In our work, therice of the used recordable compact disc with silver film is about0.2 in China, and the recordable compact disc can provide the sen-or materials for more than 100 CDtrodes. The present sensor cane used repeatedly according to acceptable results of the repeata-ility test, which suggests that the costs of glucose detections wille low.

The CDtrodes had to be stored in sealed bags in dry environ-ents at normal temperature. Their long-term stability was tested

or 4 months. The measurement results show that the response cur-ent only decreases by 3.2% after 4 months, which indicates that theDtrode is considerably stable.

.8. Detection of glucose in human blood samples

The sensor was used to determine the glucose in human bloodamples. Blood samples were obtained from healthy humans com-lied with fasting blood test requirements. 15 �L blood and 15 �L.1 mol/L PBS with two micropipettes were dropped on the surfacef the present sensor, respectively. And then, the mixture sam-le solution was mixed well in a supersonic generator with 5 s.nd then the amperometric response measurements were per-

ormed under the optimum conditions at an applied potential of0.50 V. The results of glucose concentrations in blood samples are

isted in Table 2. Recoveries in blood samples were from 95.7% to01.3%.

Accuracy tests were performed in one hospital by healthcarerofessionals and diabetic patients. The glucose concentrations

n fresh human blood samples obtained from our experimentsere compared with those measured by the hospital with YSIodel 2300 Glucose Analyzer (Yellow Springs Instruments, Yellow

prings, OH). The YSI analyzer uses a GO based method to mea-ure glucose. The results were listed in Table 3. The bias for eachample is less than 0.4 mM. Within the medical community, home

lood glucose meters are considered clinically accurate if the result

s within 20% of what a lab test would indicate [43]. This compar-son clearly shows that our results agree satisfactorily with thosebtained in the hospital.

7.51 +0.36

4. Conclusions

We have developed a non-enzymatic glucose sensor based onrecordable CDs. The maximum current response for the glucoseelectrode has been observed at pH 6.5, with a potential −0.50 Vin phosphate buffer solution. The response of the proposed elec-trode to glucose concentrations presented a good linearity overthe range of 0.5–13 mmol/L. The study offered an easy way for thedetermination of glucose in human blood directly, and it also pro-vided an approach to recycle waste CDs. The current response timefor a steady-state current was within 1 s. There was no substantialchange in current response in the presence of normal physiolog-ical concentrations of interferents (AA and UA) for the CDtrode.The applicability of the method for the determination of glucosein human blood was demonstrated. As a non-enzymatic sensor,the analytical results were satisfactory for the direct detection ofglucose in human blood. The newly developed non-enzymatic glu-cose sensor shows a number of excellent characteristics such as lowcost, fast response, acceptable sensitivity, reproducibility, selectiv-ity, and long-time stability. Compared with the existing analysisusing sensors of commercialized glucose meters, the present bio-chemical analysis of the novel amperometric sensor has to need thePBS as the supporting electrolyte. For the probable commercializa-tion, we will attempt to design a necessary kit which contains PBSwith a function of volumetric sampling. Further researches will berequired for the commercialization of this sensor.

Acknowledgements

The work was supported by the National Natural Science Foun-dation of China (Grant No. 20975091, 21075107), a project fundedby the Priority Academic Program Development of Jiangsu HigherEducation Institutions (PAPD), and the Innovation Program ofJiangsu Provincial Education Department for Postgraduate students(2011).

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Biographies

Yuxing Chen received the B.S. degree from Dezhou University, China, in 2010. Herwork is focused on the nonenzymatic glucose sensors and their potential applicationfor blood glucose detection as a postgraduate.

Lin Liu is a postgraduate student in Yangzhou University. Her research field is elec-trochemical sensors in health care.

Meirong Wang is doing research for her Master degree in Yangzhou University.Her work is focused on the electrochemical sensors and synthesis of polymers byelectrochemical methods.

Chengyin Wang is a professor in analytical chemistry at the College of Chemistry andChemical Engineering, Yangzhou University. He received his Ph.D. degree in physicalchemistry from Yangzhou University in 2007. His major research interests includebiosensor and chemical sensor, nanomaterials and nanoelectrode, chromatography.

Xiaoya Hu is a professor in analytical chemistry at the College of Chemistry andChemical Engineering, Yangzhou University. He received his Ph.D. degree in ana-lytical chemistry from Nanjing University in 1999. His main research is focused onsensors and nanotechnology.

Guoxiu Wang received his Ph.D. degree in Materials Science and Engineeringin 2001 from University of Wollongong, Australia. He is currently working as a

Professor at School of Chemistry and Forensic Science, University of Technology,Sydney, Australia, and a director of Centre for Clean Energy Technology. His majorresearch interests include nanostructured functional materials, materials chem-istry in energy storage and conversion, and development of chemical and biologicalsensors.