Poly(glycidylmethacrylate-co-vinyl ferrocene)-grafted iron oxide nanoparticles as an electron transfer mediator for amperometric phenol detection

Emre Çevik,Mehmet S¸ enel,Abdulhadi Baykal,M. Fatih Abasıyanık 한국물리학회 2013 Current Applied Physics Vol.13 No.8

An amperometric phenol biosensor was constructed by using poly(glycidylmethacrylate-co-vinyl ferrocene) grafted iron oxide nanoparticles for detection of different phenolic compounds (catechol, aminophenol, phenol, p-cresol, pyrogallol). The poly(glycidylmethacrylate-co-vinyl ferrocene) and nanoparticles were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The copolymer grafted iron oxide nanoparticles and Horseradish peroxidase (HRP) were covalently attached on gold (Au) electrode surface. The effect of pH, temperature and characteristic features such as; reusability and storage stability were studied. The electrode showed good response time within w3 s. The electrocatalytic response showed a linear dependence on the phenolic compounds concentration ranging from 0.5 to 17.0 mM.

Construction of biosensor for determination of galactose with galactose oxidase immobilized on polymeric mediator contains ferrocene

Emre Çevik,Mehmet Şenel,M. Fatih Abasıyanık 한국물리학회 2010 Current Applied Physics Vol.10 No.5

A galactose biosensor was developed by immobilizing galactose oxidase (GAox) on poly (glycidyl methacrylate-co-vinylferrocene) (poly (GMA-co-VFc)) film. The enzyme was immobilized via amine group onto polymeric mediator. The biosensor was characterized by the specific activity of the immobilized galactose oxidase, the apparent Michaelis constant , and the stability expressed by time and a number of the performed analysis. The optimized galactose biosensor exhibited a linear response range from 2 to 20 M and detection limit of 0.1 mM toward galactose. The response time of the biosensor was 5 s. The effects of the pH and the temperature of the immobilized galactose oxidase electrode were also studied.

Potentiometric urea biosensor based on poly(glycidylmethacrylate)-grafted iron oxide nanoparticles

Emre Çevik,Mehmet S¸ enel,Abdülhadi Baykal 한국물리학회 2013 Current Applied Physics Vol.13 No.1

Urease enzyme was covalently attached on the poly(glycidylmethacrylate) (PGMA)-grafted iron oxide nanoparticles on Au electrode for the fabrication of urea biosensor. The telomere of poly(- glycidylmethacrylate) (PGMA) with a trimethoxysilyl terminal group was synthesized by telomerization of glycidylmethacrylate. Iron oxide nanoparticles were coated with telomere of poly(- glycidylmethacrylate) in order to obtain good enzyme immobilization platform. The telomere and nanoparticles were characterized by using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA). The biosensor’s potentiometric response was measured as a function of urea concentration in phosphate buffer solution (10 mM, pH 7.5) and showed a linear range of 0.25e5.0 mM urea. The produced biosensor exhibited a good response time of w8 s and was stable for about two months. The basic features (optimum pH, optimum temperature, interference and storage stability) of the enzyme electrode were determined

A novel amperometric hydrogen peroxide biosensor based on pyrrole-PAMAM dendrimer modified gold electrode

Mehmet Şenel,Emre Çevik 한국물리학회 2012 Current Applied Physics Vol.12 No.4

Horseradish peroxidase (HRP) was immobilized into an electrochemically prepared copolymer of pyrroleePAMAM (PAMAM; polyamidoamine) dendrimers for the construction of amperometric hydrogen peroxide biosensor. First, second, and third generation amidoamineepyrrole dendrons having branched amine periphery and focal pyrrole functionality were synthesized via divergent pathway. Pyrrole dendrimers were covalently attached onto the electrode surface and polymerized by electrochemical copolymerization with pyrrole monomer. The synthesized dendrimers and copolymers have been characterized by FTIR-ATR and NMR. These copolymers have been utilized as conducting films for amperometric hydrogen peroxide sensing. The HRP retains its bioactivity after immobilization into the dendronized pyrrole-copolymers. Amperometric response was measured as a function of concentration of hydrogen peroxide, at fixed potential of +0.35 V vs. Ag/AgCl in a phosphate buffered saline (pH 7.5). The effect of pH and temperature of the medium, storage, and reusability properties were investigated. The results indicate an efficient immobilization of enzyme onto the PAMAM type dendrimer modified surface containing pyrrole monomer, which leads to high enzyme loading, and increased lifetime stability of the electrode. Horseradish peroxidase (HRP) was immobilized into an electrochemically prepared copolymer of pyrroleePAMAM (PAMAM; polyamidoamine) dendrimers for the construction of amperometric hydrogen peroxide biosensor. First, second, and third generation amidoamineepyrrole dendrons having branched amine periphery and focal pyrrole functionality were synthesized via divergent pathway. Pyrrole dendrimers were covalently attached onto the electrode surface and polymerized by electrochemical copolymerization with pyrrole monomer. The synthesized dendrimers and copolymers have been characterized by FTIR-ATR and NMR. These copolymers have been utilized as conducting films for amperometric hydrogen peroxide sensing. The HRP retains its bioactivity after immobilization into the dendronized pyrrole-copolymers. Amperometric response was measured as a function of concentration of hydrogen peroxide, at fixed potential of +0.35 V vs. Ag/AgCl in a phosphate buffered saline (pH 7.5). The effect of pH and temperature of the medium, storage, and reusability properties were investigated. The results indicate an efficient immobilization of enzyme onto the PAMAM type dendrimer modified surface containing pyrrole monomer, which leads to high enzyme loading, and increased lifetime stability of the electrode.

A novel thin film amperometric urea biosensor based on urease-immobilized on poly(N-glycidylpyrrole-co-pyrrole)

İbrahim Bozgeyik,Mehmet Şenel,Emre Çevik,M. Fatih Abasıyanık 한국물리학회 2011 Current Applied Physics Vol.11 No.4

An amperometric biosensor has been developed for the measurement of urea. To construct the proposed biosensor urease enzyme was immobilized onto poly(N-glycidylpyrrole-co-pyrrole) conducting film by direct covalent attachment. The biosensor surface was characterized by FTIR spectroscopy and atomic force microscopy (AFM). The response studies were carried out as a function of urea concentration with amperometric measurements. The biosensor showed a linear current response to the urea concentration ranging from 0.1 to 0.7 mM. The urea biosensor exhibited a sensitivity of 4.5 μA/mM with a response time of 4 s. The factors influencing on the performance of the resulting biosensor were also studied in detail.

A novel amperometric glucose biosensor based on reconstitution of glucose oxidase on thiophene-3-boronic acid polymer layer

Mehmet S¸ enel,Muamer Dervisevic,Emre Çevik 한국물리학회 2013 Current Applied Physics Vol.13 No.7

The biosensor was constructed for determination of glucose by using glucose oxidase enzyme immobilized on poly(thiophene-3-boronic acid) (PTBA). Boronic acid functionalized polythiophene layer was obtained by electrochemical polymerization of Thiophene (Th) and thiophene-3-boronic acid (TBA) with different monomer rations. The reconstitution of the apo-glucose oxidase (apo-GOx) on a complexed flavin adenine dinucleotide (FAD) linked to polythiophene boronic acid (PTBA) monolayer yields an electrically contacted enzyme monolayer. The GOx-reconstituted enzyme electrode exhibited excellent electrocatalytic activities toward the reduction and oxidation of hydrogen peroxide as well. The PTBA/FAD/GOx biosensor shows an excellent performance for glucose at þ0.4 V with a high sensitivity (2.14 mA/mM) and lower response time (w5 s) in a wide concentration range of 0.5e18 mM (correlation coefficient of 0.9952). Furthermore, the effects of applied potential, pH, temperature, electroactive interference, stability and reusability of the biosensors were discussed.