The aim of the submitted study is to develop molecular imprinting based surface plasmon resonance
(SPR) sensor for real-time silver ion detection. For this purpose polymeric nanofilm layer on the gold SPR
chip surface was prepared via UV polymerization of acrylic acid at 395 nm for 30 minutes. N-methacryloyl-
L cysteine used as the functional monomer to recognize the silver(I) ions from the aqueous solutions and
methylene bisacrylamide used as the crosslinker for obtaining structural rigidity of the formed cavities.
Silver(I) solutions with different concentrations were applied to SPR system to investigate the efficiency of
the imprinted SPR sensor in real time. For the control experiments, non-imprinted SPR sensor was also
prepared as described above without addition of template “silver(I) ions”. Prepared SPR sensors were
characterized with atomic force microscopy (AFM). In order to show the selectivity of the silver(I) imprinted
SPR sensor, competitive adsorption of Cu(II), Pb(II), Ni(II) ions was investigated.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3489

Denizli, A.

Ozgur, V.

Say, R.

Sener, G.

Uzun, L.

Yilmaz, E.

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 1 No 2, 02NFC21(2pp) (2012)   2304-1862/2012/1(2)02NFC21(2) 02NFC21-1  2012 Sumy State University Preparation of Ion Imprinted SPR Sensor for Real-Time Detection of Silver(I) Ion from Aqueous Solution   G. Sener1,2, E. Ozgur1, E. Yılmaz1, L. Uzun1, R. Say3, A. Denizli1  1 Hacettepe University, Faculty of Science, Department of Chemistry, Ankara 2 Hacettepe University, Institute of Science, Nanotechnology and Nanomedicine Division, Ankara 3 Anadolu University, Faculty of Science, Department of Chemistry, Eskisehir  (Received 18 June 2012; published online 22 August 2012)  The aim of the submitted study is to develop molecular imprinting based surface plasmon resonance (SPR) sensor for real-time silver ion detection. For this purpose polymeric nanofilm layer on the gold SPR chip surface was prepared via UV polymerization of acrylic acid at 395 nm for 30 minutes. N-methacryloyl-L cysteine used as the functional monomer to recognize the silver(I) ions from the aqueous solutions and methylene bisacrylamide used as the crosslinker for obtaining structural rigidity of the formed cavities. Silver(I) solutions with different concentrations were applied to SPR system to investigate the efficiency of the imprinted SPR sensor in real time. For the control experiments, non-imprinted SPR sensor was also prepared as described above without addition of template “silver(I) ions”. Prepared SPR sensors were characterized with atomic force microscopy (AFM). In  order to show the selectivity of the silver(I) imprint-ed SPR sensor, competitive adsorption of Cu(II), Pb(II), Ni(II) ions was investigated.   Keywords: Molecular imprinting, Surface Plasmon Resonance, Ion sensor, Silver(I).    PACS number: 73.20.Mf   1. INTRODUCTION  Although metals play important roles in biologi-cal processes and some of them are classified as essential elements, hazardous properties will occur when metal ions level exceeds a certain threshold concentration. Accumulation of heavy metal ions in the body leaves permanent damages and causes many diseases. For this reason, monitoring and quantification of heavy metal ions become im-portant.  Silver ions are used on the surfaces of water fil-ters due to the anti-microbial properties. In addition, silver nanoparticles are also widely used with the development in nanotechnology. Due to large scale use of silver in industrial applications, these ions contaminate water sources via leakage of the indus-trial wastes. Chronic intake of silver products to body can result in an accumulation of silver or silver sulfide particles in the skin. These particles in the skin become darker with exposure to sunlight and the skin gets a color of blue or gray which is called as argyria.  SPR is an optical technique that uses an elec-tron charge density wave phenomenon to measure changes in refractive index very close to a sensor surface. Because of unique properties of SPR sen-sors, i.e., real-time measurement, high specificity and sensitivity, no need to labeling, the applica-tions of them have been getting more popular for investigation[1]. Molecular imprinting technique, based on mo-lecular recognition, provides the polymerization of synthetic materials, which have specific binding sites and geometric shapes in their high cross-linked structure for the target analyte[2]. Molecular im-printing has been used successfully for imprinting of small molecules, metal-ions and proteins.  2. EXPERIMENTAL  2.1 Materials  L-Cysteine methylester and methacryloyl chloride was also supplied by Sigma (St Louis, USA) and used as received. N-N′-Methylenebisacrylamide (N,N′-MBAAm), was obtained from Fluka A.G. (Buchs, Switzerland). All other chemicals were of analytical grade purity and were purchased from Merck AG (Darmstadt, Germany). All water used in the experi-ments was purified by a Barnstead (Dubuque, IA) ROpure LP® reverse osmosis unit having a high flow cellulose acetate membrane (Barnstead D2731) fol-lowed by a Barnstead D3804 NANOpure® organ-ic/colloid removal and ion exchange packed-bed sys-tem.  2.2 Surface Plasmon Resonance (SPR) Appa-ratus  The recognition of the prepared polymers toward the analyte silver(I) was performed by using chips which made of a high refractive index glass prism coated with a thin gold film and the change in the incident angle (Δθ) responding to the addition of sub-strates was recorded on the SPR apparatus (Gen-optics, France)[3].  2.3 Preparation of Functional and Metal-Chelate Monomers  Briefly, the following experimental procedure was applied for the synthesis of N-methacryloly-(l)-cysteinemethylester (MAC) monomer: 5.0 g of cysteine and 0.2 g of NaNO2 were dissolved in 30 ml of K2CO3 aqueous solution (5%, v/v). This solution was cooled to 0 °C. 4.0 ml of methacryloyl chloride was poured slow-ly into this solution under nitrogen atmosphere and then, this solution was stirred magnetically at room  G. SENER, E. OZGUR, E. YILMAZ, L. UZUN, R. SAY, A. DENIZLI PROC. NAP 1, 02NFC21 (2012)   02NFC21-2 temperature for 2 h. At the end of this period, the pH of this solution was adjusted to 7.0 and was extracted with ethylacetate. The aqueous phase was evaporated in a rotary evaporator. The residue (i.e., MAC) was crystallized in ethanol and ethylacetate[4]. The complex monomer, MAC-Ag+, was prepared by slow addition of solid N-methacryloyl-(l)-cysteine methylester (MAC) into 1 ml solution of ethanol–water mixture (50/50, v/v) in a vessel followed by dis-solution of silver (I) nitrate at room temperature by constant stirring (250 rpm) for 2 h.   2.4 Preparation of Silver(I) imprinted SPR Sen-sor  In order to clean the sensor surface, the sensor was immersed in 20 mL of acidic piranha solution (3:1 H2SO4:H2O2, v/v) for 30 s. Then, it was washed with pure ethyl alcohol and dried in vacuum oven (200 mmHg, 37◦C) for 3 h. Later on, the sensor was im-mersed in ethanol/water (4:1, v/v) solution containing 3-mercaptopropene for 12 h. For the polymerization, the reaction mixture containing the metal-chelate (MAC-Ag+) monomer, N,N′-MBAAm crosslinking mon-omer, acrylic acid and initiator was prepared. Then, the reaction mixture was degassed and dropped on the gold surface of SPR sensors. Pure nitrogen gas was purged in to the cell for 5 min to evacuate the air completely since the presence of oxygen would prohibit polymeri-zation. Polymerization was carried out at room temper-ature applying UV light irradiation under nitrogen atmosphere (polymeric nanofilm layer on the gold SPR sensor surface) for 30 min. The non-imprinted polymer-coated SPR sensor, as a control, was also prepared in a similar manner in the absence of template ions by the same polymerization procedure. 2.5 Evaluation of SPR-MIP sensor response  Changes in the refractive indexes on silver (I) im-printed gold surface are recorded by a CCD camera as gray-level contrasts using surface plasmon resonance apparatus model SPR (Genoptics) which was designed and implemented using the Kretschmann configura-tion. Measurements were carried out in a Teflon cell connected to a peristaltic pump in phosphate buffer solution at room temperature.   3. RESULTS AND DISCUSSION  In this study, we have attempted combining of mo-lecular imprinting technology and SPR sensor ap-proaches and producing SPR sensor for real-time de-tection of silver(I). Silver(I) imprinted SPR sensor has a high sensitivi-ty with a wide range of silver concentrations (0.05 - 50 ppm) in aqueous solutions. The increasing concentra-tion of silver in solution caused the increasing response of the sensor, because resonance frequency shift ( R) depends on the concentration of silver(I). The results of competitive adsorption of Ag(I) with Ni(II), Cu(II), Pb(II)  indicate that Ag(I) imprinted SPR sensor have higher adsorption capabilities for Ag(I) than for other analytes. Non-imprinted SPR sensor did not give any significant response to solution containing Ag(I), Pb(II), Ni(II) and Cu(II) ions. In order to show the reproduci-bility of silver(I) imprinted SPR sensor response, three equilibration-adsorption-regeneration cycles were re-peated by aqueous silver(I) solution which has the same concentration. After the completion equilibration-adsorption-regeneration cycles, reusa-bility of the SPR sensor was determined.   REFERENCES  1. L. Uzun, R. Say, S. Ünal, A. Denizli, Biosens. Bioelectron. 24, 2878 (2009). 2. G. Sener, L. Uzun, R. Say, A. Denizli, Sens. Actuat. B 160, 791 (2011). 3. S.E. Diltemiz, R. Say, S. Buyuktiryaki, D. Hur, A. Denizli, A. Ersoz, Talanta 75, 890 (2008) 4. S. Asliyuce, N. Bereli, L. Uzun, M.A. Onur, R. Say, A. Denizli,  Sep. Purif. Technol. 73, 243 (2010).   

Preparation of Ion Imprinted SPR Sensor for Real-Time Detection of Silver(I) Ion from Aqueous Solution

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 1 No 2, 02NFC21(2pp) (2012) 
 
 
2304-1862/2012/1(2)02NFC21(2) 02NFC21-1  2012 Sumy State University 
Preparation of Ion Imprinted SPR Sensor for Real-Time Detection of Silver(I) Ion from 
Aqueous Solution  
 
G. Sener1,2, E. Ozgur1, E. Yılmaz1, L. Uzun1, R. Say3, A. Denizli1 
 
1 Hacettepe University, Faculty of Science, Department of Chemistry, Ankara 
2 Hacettepe University, Institute of Science, Nanotechnology and Nanomedicine Division, Ankara 
3 Anadolu University, Faculty of Science, Department of Chemistry, Eskisehir 
 
(Received 18 June 2012; published online 22 August 2012) 
 
The aim of the submitted study is to develop molecular imprinting based surface plasmon resonance 
(SPR) sensor for real-time silver ion detection. For this purpose polymeric nanofilm layer on the gold SPR 
chip surface was prepared via UV polymerization of acrylic acid at 395 nm for 30 minutes. N-methacryloyl-
L cysteine used as the functional monomer to recognize the silver(I) ions from the aqueous solutions and 
methylene bisacrylamide used as the crosslinker for obtaining structural rigidity of the formed cavities. 
Silver(I) solutions with different concentrations were applied to SPR system to investigate the efficiency of 
the imprinted SPR sensor in real time. For the control experiments, non-imprinted SPR sensor was also 
prepared as described above without addition of template “silver(I) ions”. Prepared SPR sensors were 
characterized with atomic force microscopy (AFM). In  order to show the selectivity of the silver(I) imprint-
ed SPR sensor, competitive adsorption of Cu(II), Pb(II), Ni(II) ions was investigated.  
 
Keywords: Molecular imprinting, Surface Plasmon Resonance, Ion sensor, Silver(I). 
 
  PACS number: 73.20.Mf 
 
 
1. INTRODUCTION 
 
Although metals play important roles in biologi-
cal processes and some of them are classified as 
essential elements, hazardous properties will occur 
when metal ions level exceeds a certain threshold 
concentration. Accumulation of heavy metal ions in 
the body leaves permanent damages and causes 
many diseases. For this reason, monitoring and 
quantification of heavy metal ions become im-
portant.  
Silver ions are used on the surfaces of water fil-
ters due to the anti-microbial properties. In addition, 
silver nanoparticles are also widely used with the 
development in nanotechnology. Due to large scale 
use of silver in industrial applications, these ions 
contaminate water sources via leakage of the indus-
trial wastes. Chronic intake of silver products to 
body can result in an accumulation of silver or silver 
sulfide particles in the skin. These particles in the 
skin become darker with exposure to sunlight and 
the skin gets a color of blue or gray which is called as 
argyria.  
SPR is an optical technique that uses an elec-
tron charge density wave phenomenon to measure 
changes in refractive index very close to a sensor 
surface. Because of unique properties of SPR sen-
sors, i.e., real-time measurement, high specificity 
and sensitivity, no need to labeling, the applica-
tions of them have been getting more popular for 
investigation[1]. 
Molecular imprinting technique, based on mo-
lecular recognition, provides the polymerization of 
synthetic materials, which have specific binding 
sites and geometric shapes in their high cross-linked 
structure for the target analyte[2]. Molecular im-
printing has been used successfully for imprinting of 
small molecules, metal-ions and proteins. 
 
2. EXPERIMENTAL 
 
2.1 Materials 
 
L-Cysteine methylester and methacryloyl chloride 
was also supplied by Sigma (St Louis, USA) and used 
as received. N-N′-Methylenebisacrylamide (N,N′-
MBAAm), was obtained from Fluka A.G. (Buchs, 
Switzerland). All other chemicals were of analytical 
grade purity and were purchased from Merck AG 
(Darmstadt, Germany). All water used in the experi-
ments was purified by a Barnstead (Dubuque, IA) 
ROpure LP® reverse osmosis unit having a high flow 
cellulose acetate membrane (Barnstead D2731) fol-
lowed by a Barnstead D3804 NANOpure® organ-
ic/colloid removal and ion exchange packed-bed sys-
tem. 
 
2.2 Surface Plasmon Resonance (SPR) Appa-
ratus 
 
The recognition of the prepared polymers toward 
the analyte silver(I) was performed by using chips 
which made of a high refractive index glass prism 
coated with a thin gold film and the change in the 
incident angle (Δθ) responding to the addition of sub-
strates was recorded on the SPR apparatus (Gen-
optics, France)[3]. 
 
2.3 Preparation of Functional and Metal-
Chelate Monomers 
 
Briefly, the following experimental procedure was 
applied for the synthesis of N-methacryloly-(l)-
cysteinemethylester (MAC) monomer: 5.0 g of cysteine 
and 0.2 g of NaNO2 were dissolved in 30 ml of K2CO3 
aqueous solution (5%, v/v). This solution was cooled to 
0 °C. 4.0 ml of methacryloyl chloride was poured slow-
ly into this solution under nitrogen atmosphere and 
then, this solution was stirred magnetically at room 
 G. SENER, E. OZGUR, E. YILMAZ, L. UZUN, R. SAY, A. DENIZLI PROC. NAP 1, 02NFC21 (2012) 
 
 
02NFC21-2 
temperature for 2 h. At the end of this period, the pH 
of this solution was adjusted to 7.0 and was extracted 
with ethylacetate. The aqueous phase was evaporated 
in a rotary evaporator. The residue (i.e., MAC) was 
crystallized in ethanol and ethylacetate[4]. 
The complex monomer, MAC-Ag+, was prepared by 
slow addition of solid N-methacryloyl-(l)-cysteine 
methylester (MAC) into 1 ml solution of ethanol–
water mixture (50/50, v/v) in a vessel followed by dis-
solution of silver (I) nitrate at room temperature by 
constant stirring (250 rpm) for 2 h.  
 
2.4 Preparation of Silver(I) imprinted SPR Sen-
sor 
 
In order to clean the sensor surface, the sensor was 
immersed in 20 mL of acidic piranha solution (3:1 
H2SO4:H2O2, v/v) for 30 s. Then, it was washed with 
pure ethyl alcohol and dried in vacuum oven (200 
mmHg, 37◦C) for 3 h. Later on, the sensor was im-
mersed in ethanol/water (4:1, v/v) solution containing 
3-mercaptopropene for 12 h. For the polymerization, 
the reaction mixture containing the metal-chelate 
(MAC-Ag+) monomer, N,N′-MBAAm crosslinking mon-
omer, acrylic acid and initiator was prepared. Then, the 
reaction mixture was degassed and dropped on the gold 
surface of SPR sensors. Pure nitrogen gas was purged 
in to the cell for 5 min to evacuate the air completely 
since the presence of oxygen would prohibit polymeri-
zation. Polymerization was carried out at room temper-
ature applying UV light irradiation under nitrogen 
atmosphere (polymeric nanofilm layer on the gold SPR 
sensor surface) for 30 min. The non-imprinted polymer-
coated SPR sensor, as a control, was also prepared in a 
similar manner in the absence of template ions by the 
same polymerization procedure. 
2.5 Evaluation of SPR-MIP sensor response 
 
Changes in the refractive indexes on silver (I) im-
printed gold surface are recorded by a CCD camera as 
gray-level contrasts using surface plasmon resonance 
apparatus model SPR (Genoptics) which was designed 
and implemented using the Kretschmann configura-
tion. Measurements were carried out in a Teflon cell 
connected to a peristaltic pump in phosphate buffer 
solution at room temperature.  
 
3. RESULTS AND DISCUSSION 
 
In this study, we have attempted combining of mo-
lecular imprinting technology and SPR sensor ap-
proaches and producing SPR sensor for real-time de-
tection of silver(I). 
Silver(I) imprinted SPR sensor has a high sensitivi-
ty with a wide range of silver concentrations (0.05 - 50 
ppm) in aqueous solutions. The increasing concentra-
tion of silver in solution caused the increasing response 
of the sensor, because resonance frequency shift ( R) 
depends on the concentration of silver(I). The results of 
competitive adsorption of Ag(I) with Ni(II), Cu(II), 
Pb(II)  indicate that Ag(I) imprinted SPR sensor have 
higher adsorption capabilities for Ag(I) than for other 
analytes. Non-imprinted SPR sensor did not give any 
significant response to solution containing Ag(I), Pb(II), 
Ni(II) and Cu(II) ions. In order to show the reproduci-
bility of silver(I) imprinted SPR sensor response, three 
equilibration-adsorption-regeneration cycles were re-
peated by aqueous silver(I) solution which has the 
same concentration. After the completion equilibration-
adsorption-regeneration cycles, reusa-bility of the SPR 
sensor was determined. 
 
 
REFERENCES 
 
1. L. Uzun, R. Say, S. Ünal, A. Denizli, Biosens. Bioelectron. 
24, 2878 (2009). 
2. G. Sener, L. Uzun, R. Say, A. Denizli, Sens. Actuat. B 160, 
791 (2011). 
3. S.E. Diltemiz, R. Say, S. Buyuktiryaki, D. Hur, A. Denizli, 
A. Ersoz, Talanta 75, 890 (2008) 
4. S. Asliyuce, N. Bereli, L. Uzun, M.A. Onur, R. Say, 
A. Denizli,  Sep. Purif. Technol. 73, 243 (2010). 
 
 


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Preparation of Ion Imprinted SPR Sensor for Real-Time Detection of Silver(I) Ion from Aqueous Solution

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