Go

CSa

b

c

ARRAA

KGSLHO

1

robattaowcuaspl

f

Sf

s

0h

Sensors and Actuators B 183 (2013) 144– 149

Contents lists available at SciVerse ScienceDirect

Sensors and Actuators B: Chemical

journa l h om epage: www.elsev ier .com/ locate /snb

reen synthesis of silver nanoparticles and their application for the developmentf optical fiber based hydrogen peroxide sensor

handrakant K. Tagada,b, Sreekantha Reddy Dugasanic, Rohini Aiyerb, Sungha Parkc, Atul Kulkarnib,∗,ushma Sabharwala,b,∗∗

Biochemistry Division, Department of Chemistry, University of Pune, Pune 411007, IndiaCentre for Sensor Studies, Department of Electronic Science, University of Pune, Pune 411007, IndiaSungkyunkwan Advanced Institute of Nanotechnology (SAINT) and Department of Physics, Sungkyunkwan University, Suwon 440746, South Korea

a r t i c l e i n f o

rticle history:eceived 27 December 2012eceived in revised form 21 March 2013ccepted 25 March 2013vailable online xxx

a b s t r a c t

Green synthesis of nanoparticles and their applications in sensing area is of great interest to the researchcommunity. Herein we report a green approach for the synthesis of silver nanoparticles (Ag NPs) by usinglocust bean gum (LBG) polysaccharide and its application to detect hydrogen peroxide (H2O2). Ag NPswere synthesized by mixing optimized weight percent of LBG with a known quantity of silver nitrate(AgNO3) at 55–60 ◦C. Synthesized Ag NPs were characterized by UV–vis spectroscopy and atomic force

eywords:reen synthesisilver nanoparticlesocust bean gumydrogen peroxide

microscopy (AFM). The size of synthesized Ag NPs was in the range of 18–51 nm depending upon theconcentration of LBG and AgNO3. Further, a low cost and portable optical fiber based sensor using LBGstabilized Ag NPs was developed for monitoring the H2O2 concentration as low as 0.01 mM.

© 2013 Elsevier B.V. All rights reserved.

ptical fiber sensor

. Introduction

Nanoparticles (NPs) have received considerable attention inecent years due to their wide range of applications in the fieldf catalysis, optoelectronics, chemical sensing, bio-sensing andiotechnology [1,2]. In most of the cases, the chemical route isdopted for the synthesis of various NPs; however, this has poten-ial hazards to health and environment. Hence in recent yearshe green synthesis approach has emerged as one of the activereas of research. Green synthesis of NPs has several advantagesver chemical synthesis, such as simplicity, cost effectiveness asell as compatibility for biomedical and pharmaceutical appli-

ations [3]. Green synthesis of silver nanoparticles (Ag NPs) bysing plant leaf extracts, seed extracts, plant latex, microorganismsnd some biopolymers have been reported earlier [4]. Polymers

uch as polyethylene glycol [5], polyvinylpyrrolidone (PVP) [6],olyacrylonitrile (PAN) [7], poly(methyl methacrylate) [8], polyani-

ine [9] and poly (vinyl alcohol) [10]. have been widely used as

∗ Corresponding author. Tel.: +91 20 25601414;ax: +91 20 25699841.∗∗ Corresponding author at: Centre for Sensor Studies, Department of Electroniccience, University of Pune, Pune 411007, India. Tel.: +91 20 25696061;ax: +91 20 25691728.

E-mail addresses: atul.css@unipune.ac.in (A. Kulkarni),sab@chem.unipune.ac.in (S. Sabharwal).

925-4005/$ – see front matter © 2013 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.snb.2013.03.106

reducing and stabilizing agent for synthesis of well-dispersed AgNPs. Biopolymers like natural rubber [11], polysaccharides [12],cellulose [13], gum acacia polymer [14], and starch [15] have beenused as matrices or stabilizers for the synthesis of NPs because oftheir biocompatibility and nontoxic nature. However, locust beangum (LBG) has not been explored yet as a reducing and stabilizingagent for Ag NPs.

Hydrogen peroxide (H2O2) is widely used in water treatmentplants, for disinfection, cleaning microcircuits and other indus-tries [16]. The determination of H2O2 level is of great importance,as it is found to induce many kinds of cellular damages even atrelatively low concentration. Also its concentration needs to bemonitored especially in food and pharmaceutical industries andclinical laboratories [16–18]. Detection of H2O2 has been carriedout using several analytical techniques like spectrophotometer [19]and chemiluminescence [20]. Several reports are available on appli-cation of Ag NPs for detection of H2O2 by amperometric [21] as wellas electrochemical [22,23] methods. In addition H2O2 sensing basedon decolorization of Ag NPs using spectrophotometer has also beenreported [18,24]. However, these instruments are bulky, costly andnot portable. Therefore there is a need to develop a portable andeasy-to-use sensor for the detection of H2O2.

Currently fiber optic sensors have gained considerable attentionin bio-chemical fields due to their unique characteristics such assmall size, light weight and high flexibility [25]. Most of the fiberoptic chemical sensor principles are based on the monitoring of

Actuators B 183 (2013) 144– 149 145

aa

bdv

2

2

fwfAi

2

1flAE6A7bNctcower1

2

trwA(u

2

scbUwTStiictt

at 424 nm, indicated the formation of Ag NPs [15].Absorbance wasfound to increase as a function of reaction time and was highest for72 h of incubation. This increase in absorption intensity with time

C.K. Tagad et al. / Sensors and

bsorbance, reflectance, luminescence, change in refractive indexnd light scattering [26–29].

In the present work, we describe the green synthesis of Ag NPsy using LBG. Further, we report the application of Ag NPs for theevelopment of a portable optical fiber based sensor to monitorariations in the H2O2 concentration.

. Experimental

.1. Materials

Silver nitrate (AgNO3, analytical-reagent-grade) was purchasedrom Sisco Research Laboratory, India. 30% (w/v) H2O2 solutionas purchased from Qualigens Fine Chemicals, India. LBG extracted

rom the seeds of Ceratonia siliqua was purchased from Sigmaldrich India and used without any pretreatment. All solutions used

n the experiments were prepared using deionized water.

.2. Synthesis of silver nanoparticles

For the synthesis of Ag NPs, 0.1 gm of LBG was dissolved in00 ml deionized water by heating at 80 ◦C under constant stirringor dissolution of LBG to achieve 0.1% (w/v) solution. After disso-ution, LBG solution was brought to room temperature. 25 ml ofg NO3 (1 mM) solution was then added to the LBG solution inrlenmeyer flask at room temperature and the mixture was kept at0 ◦C in an incubator to carry out the reaction of Ag NPs synthesis.liquots from the reaction bulk were withdrawn at 6, 24, 48, and2 h of time interval and the synthesis of Ag NPs was monitoredy UV–vis spectroscopy. The effect of AgNO3 concentration on AgPs synthesis was evaluated by carrying out reaction at differentoncentrations of AgNO3 (1 mM–5 mM) where the LBG concentra-ion was kept constant at 0.1% (w/v). Similarly the effect of LBGoncentration on the synthesis of Ag NPs was studied by carryingut reactions at various concentrations of LBG (0.1 to 0.4% (w/v))here the AgNO3 concentration was kept constant at 1 mM. The

ffect of pH on the synthesis of Ag NPs was studied by carrying outeactions at different pH (pH 4, 6, 8, 10 and 12) using 0.1% LBG and

mM Ag NO3.

.3. Characterization

UV–vis analysis was performed on Shimadzu 1800 UV spec-rophotometer operated at a resolution of 1 nm as a function ofeaction time during the synthesis of Ag NPs. A control was run inhich only AgNO3 solution was used without the reducing agent.FM images were obtained by Digital Instruments Nanoscope III

Vecco, USA) with a multimode fluid cell head by liquid tappingsing a NP-S oxide-sharpened silicon nitride tip (Vecco, USA).

.4. Fabrication of optical fiber sensor

The polymer optical fiber (POF) was used to fabricate a U bentensing probe for the detection of H2O2. The protecting jacket andlad of 2 cm was removed [26] and the un-cladded region wasent in U-shape keeping the bend diameter to 5 mm to form the-bent fiber optic sensing probe. A similar U-bent sensing probeas reported earlier for humidity sensing [27,28] by our group.

he RED light is launched in the fiber by using transmitter (660 nm,FH 756 V, Siemens) and the light through the fiber is received byhe photo detector (200–1100 nm, SFH350, Siemens) as depictedn Fig. 1. The sensing region of fiber optic probe was then dipped

n a cell containing reaction mixtures (Ag NPs and different con-entrations of H2O2 in 1:1 proportion) and the output voltage fromhe detector was recorded as a function of time using a multime-er (2000, Keithley, USA). The reaction was monitored for up to

Fig. 1. Experimental set up for optical fiber based sensor for detection of hydrogenperoxide.

1200 s. Different concentrations of H2O2 (0.01 mM, 0.1 mM, 1 mMand 10 mM) were used to measure the sensing response. The exper-iments were carried out at normal room temperature and pressure.

3. Results and discussion

3.1. Synthesis of silver nanoparticles

In this study low cost LBG has been used as a reducing and sta-bilizing agent for the synthesis of Ag NPs. Scheme 1 gives a briefillustration of the synthesis of Ag NPs embedded in LBG polymermatrix. The mixture of optimized concentrations of LBG and AgNO3was incubated for 6–72 h around 60 ◦C to achieve the synthesis ofAg NPs (orange color spheres). LBG is a polyhydroxylated biopoly-mer consisting of (1 → 4)-linked �-d-mannopyranose backbonewith branch points from their 6-positions linked to �-d-galactose(that is, 1 → 6-linked �-d-galactopyranose) [30]. Polyhydroxylatedmacromolecules possess inter and intramolecular hydrogen bond-ing resulting in network formation within the polymer chain whichacts as templates for nanoparticle growth [15]. The extensive num-ber of hydroxyl groups and a hemiacetal reducing ends on LBGpolysaccharide act as active reaction centers to facilitate the reduc-tion of Ag+ to Ag0. Ag NPs thus formed, get embedded and stabilizedwithin the polymer matrix.

UV–vis absorption spectra of Ag NPs synthesized using 1 mMAgNO3 solution and 0.1% LBG at 60 ◦C, recorded as a function of reac-tion time is shown in Fig. 2. The appearance of a single, bell shaped,surface plasmon band at the wavelength of maximum absorbance

Fig. 2. UV–vis spectra recorded as a function of reaction time for Ag NPs synthesizedusing 1 mM AgNO3 and 0.1% LBG solution at 60 ◦C.

146 C.K. Tagad et al. / Sensors and Actuators B 183 (2013) 144– 149

S trix. T6 rprett

siww

3n

fciitrmwsow

ic2

Foi

cheme 1. Brief illustration of synthesis of Ag NPs embedded in LBG polymer ma0 ◦C for 6–72 h to achieve the synthesis of Ag NPs (orange color spheres). (For intehe article.)

ignifies enhanced reduction of Ag+ to form Ag NPs. No significantncrease in absorbance was observed after 72 h of reaction time,

hich indicates the completion of reaction. Hence the reaction timeas optimized to 72 h.

.2. Effect of AgNO3 concentration on synthesis of silveranoparticles

The UV–vis absorption spectra of Ag NPs prepared using dif-erent concentrations of AgNO3 (1 mM–5 mM), where the LBGoncentration was kept constant at 0.1% (w/v) is depicted in Fig. 3. Its observed that the absorption intensity increases with an increasen AgNO3 concentration, which shows efficient reduction of Ag+

o Ag NPs at higher concentration of AgNO3. The data reveal thategardless of the AgNO3 concentration used, similar surface plas-on bands are formed with the formation of the ideal bell shapehich is characteristic for the formation of Ag NPs. Inset of Fig. 3

hows change in color of Ag NPs colloid at different concentrationsf AgNO3. The color of the solutions is increasingly becoming brownith an increase in the concentration of AgNO3.

An increase in the number of Ag NPs was observed with anncrease in the concentration of AgNO3. The nanoparticles size wasalculated from the AFM images. The size of nanoparticles is around2 ± 6 nm for 1 mM silver nitrate as shown in Fig. 4(a). For other

ig. 3. UV–vis spectra of silver nanoparticles synthesized at different concentrationsf AgNO3 and 0.1% LBG at 60 ◦C. Inset figure shows change in color of Ag NPs withncrease in concentration of AgNO3.

he mixture of optimized concentrations of LBG and AgNO3 was incubated aroundation of the references to color in text, the reader is referred to the web version of

concentrations of Ag NO3, the size of Ag NPs was observed rela-tively in wide range with increase in particle density as shown inFig 4b–d.

3.3. Effect of LBG concentration on synthesis of silvernanoparticles

UV–vis absorbance spectra of Ag NPs prepared using differentconcentrations of LBG (0.1, 0.2, 0.3 and 0.4%) where the AgNO3concentration was kept constant at 1 mM is shown in Fig. 5 Theabsorption peak was observed in the visible range at 424 nm and418 nm for 0.1% and 0.2% LBG respectively which indicates blueshift with increasing concentration of LBG and thus reduction inthe particle size as observed for other polymers [31]. No significantabsorption peak was observed for Ag NPs synthesized with 0.3%and 0.4% LBG solution. Absorption intensity expected to increasewith increase in concentration of LBG as it is a reducing andstabilizing agent. But it is found to decrease with increased con-centration of LBG. This suggests that at a higher concentration ofLBG, nanoparticles were more strongly capped and deeply embed-ded in the viscous polymer matrix. Under these conditions lightmay not effectively interact with nanoparticles. This retards thecoalescence process and decreases UV–vis absorption peak inten-sity as observed for other viscous solutions [32]. Secondly the AgNPs formation may reduce at high concentration of LBG. This isbecause of high viscosity of LBG at its higher concentrations. As LBGis a biopolymer, at its lower concentrations, the polymer chainsare free to expand and expose the functional groups which arereadily available for the reduction of Ag+. As concentration of LBGis increased, viscosity of the solution also increases reducing themovement and diffusion of the Ag+ to get access for the functionalgroups. Hence less reduction of Ag+ to Ag0 takes place resulting inreduced absorption peak intensity.

3.4. Effect of pH on the synthesis of Ag NPs.

The pH of solution plays a crucial role in the synthesis of Ag NPs[33]. The effect of pH on the synthesis of Ag NPs was studied bycarrying out reactions at different pH (pH 4, 6, 8, 10 and 12) using0.1% LBG and 1 mM Ag NO3. At acidic pH (pH 4 and 6), no surfaceplasmon peak was observed in the visible region which is a charac-teristic for Ag NPs. This suggests that acidic pH is not favorable forthe Ag NPs synthesis. As seen in Fig. 6, an increase in the intensityof surface plasmon peak was observed under alkaline conditions(pH 8, 10 and 12) due to the increased formation of Ag NPs. Yellow-

ish color appears at pH 8 which gradually changes to dark yellowat pH 10 and further brown at pH 12. However at pH 12, agglom-eration of Ag NPs was observed whereas no agglomeration wasobserved at pH 10. This indicates poor stability of Ag NPs at extreme

C.K. Tagad et al. / Sensors and Actuators B 183 (2013) 144– 149 147

F ons of

ae

3

iAcs[

FtN

ig. 4. AFM analysis of Ag-NPs synthesized using 0.1% LBG and different concentrati

lkaline pH. These observations are well in agreement with thearlier reports [33].

.5. Evaluation of optical fiber based H2O2 sensor

H2O2 is a strong oxidizing agent. It oxidizes Ag NPs and convertst from Ag0 to Ag+ form loosing the characteristics of nanoparticles.

s a result, the Ag NPs solution, originally yellow in color, graduallyhanged to colorless. Hence, a remarkable change in the localizedurface plasmon resonance absorbance strength was also observed18,24].

ig. 5. UV–vis spectra of silver nanoparticles synthesized using different concen-rations of LBG and 1 mM AgNO3 at 60 ◦C. Inset figure shows change in color of AgPs at different LBG concentrations.

AgNO3. Size of Ag NPs with 1–5 mM AgNO3 is shown in images (a)–(e), respectively.

The optical fiber sensor response for different concentrations ofH2O2 is shown in Fig. 7. It is observed that the output voltage forblank (Ag NPs without H2O2) increases for certain time (∼400 s)and then reaches to a constant value. During this time, backscat-tered light from Ag NPs colloid gets confined in the optical fiberwaveguide to give maximum power output in the form of volt-age. This is mainly due to mirror like behavior of Ag NPs presentaround the sensing area of the optical fiber probe. Therefore allthe comparisons, after addition of H2O2 in the Ag NPs, were made

at 400 s. It was observed that, in presence of H2O2 output volt-age decreases linearly as a function of reaction time. Inset of Fig. 7shows decrease in output voltage as a function of H2O2 concentra-tion. In order to confirm that the change in output voltage of the

Fig. 6. UV–vis spectra of Ag NPs synthesized at different pH.

148 C.K. Tagad et al. / Sensors and Actuators B 183 (2013) 144– 149

Fig. 7. Change in output voltage for different concentrations of H2O2 as a functiono1

sLctioonssNtitos

two(a

csHAtrt

sitHibetob

f time. Inset figure shows output voltage for different samples at 400 s. Samples–5 represents 0.0 mM, 0.01 mM, 0.1 mM, 1 mM, and 10 mM H2O2.

ensor is due to H2O2 only, deionized water was introduced intoBG stabilized Ag NPs which was used as a blank or reference. Nohange in voltage was observed for the reference. Three major fac-ors are contributing to the sensitivity: (a) degradation of Ag NPsn presence of H2O2, (b) change in the refractive index by additionf H2O2 and (c) backscattering of light due to Ag NPs. Oxidationf Ag NPs by H2O2 leads to the degradation and decolorization ofanoparticles. Decreased concentration of Ag NPs and color of theuspension result in to change in the refractive index of mediumurrounding the sensing region. As the effective concentration of AgPs is decreased with increased concentration of H2O2, backscat-

ering of light from the nanoparticle surface also decreases resultingn decreased power output from the detector. This is mainly dueo mirror like behavior of Ag NPs present around the sensing areaf the optical fiber probe and backscattering of light from metalurface [34].

In order to evaluate the degree of degradation of Ag NPs duringhe reaction between Ag NPs and H2O2, % sensitivity factor (% SF)as calculated and plotted as a function of different concentration

f H2O2 as depicted in Fig. 8(a). % SF is calculated by using formulaV0 − (V1/V0)) × 100. Where, V0 and V1 refer to the output voltaget 400 s for Ag NPs without and with H2O2 respectively.

A sharp increase in % SF was observed with increase in con-entration of H2O2 from 0.01 mM to 1 mM. However a relativelymaller change was observed for 10 mM as compared to 1 mM of2O2 concentration. This suggests that the degree of conversion ofg NPs increases sharply with increase in concentration of H2O2 up

o 1 mM. Beyond this concentration total number of Ag NPs withespect to the concentration of H2O2 were less for the reaction toake place.

To calibrate the sensor response, the output voltage of the sen-or was plotted as a function of concentration of H2O2 as shownn Fig. 8(b). The graph clearly shows that up to the concentra-ion of 1 mM, output voltage decreased linearly as a function of2O2 whereas at the concentration of 10 mM of H2O2, the decrease

n output voltage was nonlinear. This may be attributed to theackscattering/non-specular reflection of the scattered light in the

vanescent waves due to Ag NPs. When H2O2 concentration is zero,he maximum transmitted light intensity in terms of voltage wasbserved. When H2O2 was added, the output voltage decreasedecause the Ag NPs were getting oxidized to Ag+ form with the loss

Fig. 8. (a) Relative change in % sensitivity factor for different concentrations of H2O2.(b) Change in output voltage of the sensor with increase in the concentrations ofH2O2 at 400 s.

of the characteristic color of the Ag NPs. Since the Ag NPs reducedin number with increasing concentration of H2O2, a reduction inbackscattering of the light led to a decreased in transmitted light.

4. Conclusion

In this work, we have reported a simple, eco-friendly, one-potsynthetic route to prepare silver nanoparticles, by using LBG asa reducing and stabilizing agent. The Ag-NPs synthesized by thismethod were found to be stable over 7 months of period understudy. The LBG stabilized Ag NPs were successfully employed inthe fabrication of optical fiber based sensor for the detection ofH2O2. The developed fiber optic sensor for the detection of H2O2 issimple, cost effective and portable and can be adopted in variousindustrial/research applications.

References

[1] N. Krasteva, I. Besnard, B. Guse, R.E. Bauer, K. Mullen, A. Yasuda, et al., Self-assembled gold nanoparticle/dendrimer composite films for vapor sensingapplications, Nano Letters 2 (2002) 551–555.

Actua

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

C.K. Tagad et al. / Sensors and

[2] T. Prow, J.N. Smith, R. Grebe, J.H. Salazar, N. Wang, N. Kotov, et al., Construction,gene delivery, and expression of DNA tethered nanoparticles, Molecular Vision12 (2006) 606–615.

[3] E.S. Abdel-Halim, M.H. El-Rafie, S.S. Al-Deyab, Polyacrylamide/guar gum graftcopolymer for preparation of silver nanoparticles, Carbohydrate Polymers 85(2011) 692–697.

[4] V.K. Sharma, R.A. Yngard, Y. Lin, Silver nanoparticles: green synthesis and theirantimicrobial activities, Advances in Colloid and Interface Science 145 (2009)83–96.

[5] C.C. Luo, Y.H. Zhang, X.W. Zeng, Y.W. Zeng, Y.G. Wang, The role of poly(ethyleneglycol) in the formation of silver nanoparticles, Journal of Colloid and InterfaceScience 288 (2005) 444–448.

[6] M.P. Zheng, M.Y. Gu, Y.P. Jin, G.L. Jin, Optical properties of silver-dispersed PVPthin film, Materials Research Bulletin 36 (2001) 853–859.

[7] Z.P. Zhang, L.D. Zhang, S.X. Wang, W. Chen, Y. Lei, A convenientroute to polyacrylonitrile/silver nanoparticle composite by simultaneouspolymerization-reduction approach, Polymer 42 (2001) 8315–8318.

[8] N. Singh, P.K. Khanna, In situ synthesis of silver nano-particles in polymethyl-methacrylate, Materials Chemistry and Physics 104 (2007) 367–372.

[9] P.K. Khanna, N. Singh, S. Charan, A.K. Viswanath, Synthesis of Ag/polyanilinenanocomposite via an in situ photo-redox mechanism, Materials Chemistryand Physics 92 (2005) 214–219.

10] Y. Zhou, S.H. Yu, C.Y. Wang, X.G. Li, Y.R. Zhu, Z.Y. Chen, A novel ultravioletirradiation photoreduction technique for the preparation of single-crystal Agnanorods and Ag dendrites, Advanced Materials 11 (1999) 850–852.

11] N.H.H. Abu Bakar, J. Ismail, M. Abu Bakar, Synthesis and characterization ofsilver nanoparticles in natural rubber, Materials Chemistry and Physics 104(2007) 276–283.

12] H.Z. Huang, X.R. Yang, Synthesis of polysaccharide-stabilized gold and silvernanoparticles: a green method, Carbohydrate Research 339 (2004) 2627–2631.

13] J. Cai, S. Kimura, M. Wada, S. Kuga, Nanoporous, Cellulose as metal nanoparticlessupport, Biomacromolecules 10 (2009) 87–94.

14] Y.M. Mohan, D.K. Joseph, K.E. Geckeler, Poly(N-isopropylacrylamide-co-sodium acrylate) hydrogels: interactions with surfactants, Journal of AppliedPolymer Science 103 (2007) 3423–3430.

15] P. Raveendran, J. Fu, S.L. Wallen, Completely, green synthesis and stabilizationof metal nanoparticles, Journal of the American Chemical Society 125 (2003)13940–13941.

16] J. Wang, Y. Lin, L. Chen, Organic-phase biosensor for monitoring phenol andhydrogen peroxide in pharmaceutical antibacterial products, Analyst 118(1993) 277–280.

17] W. Lei, A. Durkop, Z.H. Lin, M. Wu, O.S. Wolfbeis, Detection of hydrogen peroxidein river water via a microplate luminescence assay with time-resolved (gated)detection, Microchimica Acta 143 (2003) 269–274.

18] P. Vasileva, B. Donkova, I. Karadjova, C. Dushkin, Synthesis of starch-stabilizedsilver nanoparticles and their application as a surface plasmon resonance-based sensor of hydrogen peroxide, Colloid Surface A 382 (2011) 203–210.

19] J.E. Frew, P. Jones, G. Scholes, Spectrophotometric determination of hydro-gen peroxide and organic hydropheroxides at low concentrations in aqueoussolution, Analytica Chimica Acta 155 (1983) 139–150.

20] A. Tahirovic, A. Copra, E. Omanovic-Miklicanin, K. Kalcher, A chemi-luminescence sensor for the determination of hydrogen peroxide, Talanta 72(2007) 1378–1385.

21] M.R. Guascito, E. Filippo, C. Malitesta, D. Manno, A. Serra, A. Turco, A new amper-ometric nanostructured sensor for the analytical determination of hydrogenperoxide, Biosensors and Bioelectronics 24 (2008) 1057–1063.

22] H.H. Chen, Z. Zhang, D.Q. Cai, S.Y. Zhang, B.L. Zhang, J.L. Tang, et al., A hydro-gen peroxide sensor based on Ag nanoparticles electrodeposited on naturalnano-structure attapulgite modified glassy carbon electrode, Talanta 86 (2011)266–270.

23] W. Zhao, H.C. Wang, X. Qin, X.S. Wang, Z.X. Zhao, Z.Y. Miao, et al., A novelnonenzymatic hydrogen peroxide sensor based on multi-wall carbon nan-otube/silver nanoparticle nanohybrids modified gold electrode, Talanta 80(2009) 1029–1033.

24] E. Filippo, A. Serra, D. Manno, Poly(vinyl alcohol) capped silver nanoparticles aslocalized surface plasmon resonance-based hydrogen peroxide sensor, Sensorsand Actuators B: Chemical 138 (2009) 625–630.

25] R. Amin, A. Kulkarni, T. Kim, S.H. Park, DNA thin film coated optical fiber biosen-sor, Current Applied Physics 12 (2012) 841–845.

tors B 183 (2013) 144– 149 149

26] A. Kulkarni, J.H. Lee, J.D. Nam, T. Kim, Thin film-coated plastic optical fiber probefor aerosol chemical sensing applications, Sensors and Actuators B: Chemical150 (2010) 154–159.

27] A. Cusano, M. Giordano, A. Cutolo, M. Pisco, M. Consales, Integrated develop-ment of chemoptical fiber nanosensors, Current Analytical Chemistry 4 (2008)296–315.

28] M.V. Fuke, P. Kanitkar, M. Kulkarni, B.B. Kale, R.C. Aiyer, Effect of particle sizevariation of Ag nanoparticles in polyaniline composite on humidity sensing,Talanta 81 (2010) 320–326.

29] A. Vijayan, M. Fuke, R. Hawaldar, M. Kulkarni, D. Amalnerkar, R.C. Aiyer, Opticalfibre based humidity sensor using co-polyaniline clad, Sensors and ActuatorsB: Chemical 129 (2008) 106–112.

30] D.E. Dunstan, Y. Chen, M.L. Liao, R. Salvatore, D.V. Boger, M. Prica, Structure andrheology of the kappa-carrageenan/locust bean gum gels, Food Hydrocolloid15 (2001) 475–484.

31] J. Yan, G. Zou, A. Wu, J. Ren, J. Yan, A. Hu, L. Liu, Y.N. Zhou, Effect of PVP on thelow temperature bonding process using polyol prepared Ag nanoparticle pastefor electronic packaging application, Journal of Physics: Conference Series 379(2012) 012024.

32] S.K. Ghosh, S. Kundu, M. Mandal, S. Nath, T. Pal, Studies on the evolution ofsilver nanoparticles in micelle by UV-photoactivation, Journal of NanoparticleResearch 5 (2003) 577–587.

33] C. Krishnaraj, R. Ramachandran, K. Mohan, P.T. Kalaichelvan, Optimization forrapid synthesis of silver nanoparticles and its effect on phytopathogenic fungi,Spectrochimica Acta Part A 93 (2012) 95–99.

34] A. Centeno, J. Breeze, B. Ahmed, H. Reehal, N. Alford, Scattering of light intosilicon by spherical and hemispherical silver nanoparticles, Optics Letters 35(2010) 76–78.

Biographies

Chandrakant Tagad received his Masters degree in Biochemistry from the Depart-ment of Chemistry, University of Pune, India, in 2010. Currently he is pursuing hisPh.D. degree at the University of Pune. His research interests are protein biochem-istry, bio-nanotechnology and biosensors.

Sreekantha Reddy Dugasani received his Ph.D. degree in 2007 from the Departmentof Physics, Sri Venkateswara University in India. He is currently a Research Professorin the Department of Physics at Sungkyunkwan University in South Korea. Currentlyhe is working on the field of DNA nanotechnology especially in physical applicationsusing biological materials.

Rohini Aiyer graduated from the Pune University with B.Sc. in physics and M.Sc.in electronics and received her Ph.D. in physics from Pune University in 1979, andis currently working as a Professor of Physics in the University of Pune, India. Herresearch interests are sensors, microwaves, laser applications, resonators and non-linear optical properties of quantum dots. Prof. R.C. Aiyer has published 80 researchpapers in peer-reviewed International Journals of High Repute.

Sungha Park received his Ph.D. degree in 2005 from the Department of Physics atDuke University, USA. Currently he is an Assistant Professor in the Department ofPhysics at Sungkyunkwan University in South Korea. His research interests are inexperimental nano/bio sciences such as physical/biological circuit design and devicefabrication using nanoscale materials, bottom-up self-assembly using biomaterials,and applications based on the biological nanostructures.

Atul Kulkarni received his Ph.D. degree from the University of Pune, India, in2005. His research topic involved multidisciplinary sensors. From 2006 to 2012,he had been a Research Professor at Sungkyunkwan University, NanoparticleTechnology Lab, School of Mechanical Engineering, South Korea. Currently heis associated with Center for Sensor Studies, University of Pune from February2012. His research interests include developing sensors using optical, nano, andbiotechnology.

Sushma Sabharwal received her M.Sc. and Ph.D. in Biochemistry from the Universityof Pune, India, in 1988. Since then she is a faculty in Department of Chemistry, Uni-versity of Pune. Her research interests include biochemical aspects of plant enzymeinhibitors, lectins, Glycosidases and biosesnors.