A benzimidazole-based conducting polymer and a PMMA–clay nanocomposite containing biosensor platform for glucose sensing (original) (raw)
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Biosensors based on oxidases immobilized in various conducting polymers
Sensors and Actuators B: Chemical, 1995
The electrodeposited organic polymers polypyrrole, poly(N-methylpyrrole), poly(u-phenylenediamine) and polyaniline are compared as matrices for the immobilization of glucose oxidase in the preparation of amperometric glucose biosensors. Enzyme entrapment in the polymer layer is obtained by electrodeposition of polymers from solutions of monomers containing dissolved enzyme. For all examined sensors a useful and almost linear range of response to glucose is observed up to at least 20 mM of glucose. The best sensitivity of response is obtained for a glucose sensor made of poly(o-phenylenediamine) and polypyrrole. A linear response up to 20 mM glucose is also obtained in flow-injection measurements for a glucose/polypyrrole sensor. Poly(o-phenylenediamine) is also used for satisfactory immobilization of choline oxidase in the preparation of a choline sensor, whereas a lactate biosensor has been prepared by immobilization of lactate oxidase in polypyrrole.
Electroanalysis, 2013
Surface functionalization plays a crucial role in the design of biosensors. For this purpose, a novel functional monomer, 6-(4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2H-benzo[d][1,2,3]triazol-2-yl)hexan-1-amine (BEDOA-6), was designed and synthesized. Poly(BEDOA-6) was utilized as an immobilization matrix for glucose oxidase biosensor construction. Moreover, polymethylmethacrylate (PMMA) layered silicate nanocomposites were prepared by in situ suspension polymerization. Conducting polymer surface was modified with PMMA/clay nanocomposite material and a glucose biosensor was developed. In addition, XPS and SEM were utilized to characterize the surface properties. The biosensor shows a wide linear range between 2.8 mM and 1.2 mM to glucose with a low detection limit of 1.99 mM. Finally, the biosensor was tested on serum samples containing actual human blood. The results were in well-agreement with a reference method.
Materials Science and Engineering: C, 2006
ABSTRACT In order to determine the best kind of matrix that enables preservation of the enzymatic and electro-enzymatic activity of immobilized enzyme and provides accessibility towards substrate, various host materials (electropolymerized polypyrrole films, alginate polysaccharide, biocompatible synthetic latex and inorganic clays (laponite and layered double hydroxides LDHs), differing in permeability, ion exchange properties and hydrophobic–hydrophilic character, were compared for the fabrication of amperometric glucose biosensors. The electrochemical assays were performed by potentiostating the enzyme electrodes at 0.6 V vs. Ag/AgCl in order to oxidize the hydrogen peroxide enzymatically generated in the presence of glucose and oxygen. The highest sensitivity and maximum current density were recorded for laponite (82.3 mA M−1 cm−2 and 410 μA cm−2 respectively) and LDHs (55 mA M−1 cm−2 and 417 μA cm−2, respectively).
Applied Clay Science, 2013
Palygorskite (Pal) may be a promising material for enzyme immobilization due to its large surface, high biocompatibility and stability. This attractive material combined with a conducting polymer, poly(ophenylenediamine), was exploited as a platform for the immobilization of glucose oxidase (GOD) using glutaraldehyde as crosslinker, and thus a novel glucose biosensor was obtained. The results of electrochemical impedance spectroscopy (EIS) and SEM indicated the successful entrapment of GOD in the clay polymer nanocomposite (CPN) film. Amperometric detection of glucose was performed by holding the potential at the CPN electrode at 0.6 V for the oxidation of H 2 O 2 generated in the enzymatic reaction. The apparent Michaelis-Menten constant (K M app ) was calculated to be 5.25 mM, which is close to that of the free enzyme. The proposed biosensor exhibited a wide linear range, a low detection limit, a good reproducibility and accepted stability in the determination of glucose, providing a biocompatible platform for glucose biosensing.
describes an amperometric sensor application of a new class of triazine-centered monomers functionalized with different numbers of carbazole and hydrazine. In the sensor system, carbazole and hydrazine are designed as transducer and enzyme crosslinker groups, respectively. The monomers (TECA and CTDA) containing different numbers of carbazole and hydrazine were electrochemically polymerized on a graphite (GR) electrode. A new sensor platforms for glucose determination have been obtained by immobilizing glucose oxidase (GOx) on the polymer film surfaces. The pTECA/GOx and pCTDA/GOx-based electrodes were investigated for an evaluation of electron transfer between the enzyme and electrode at bioelectrochemically relevant potentials via pTECA and pCTDA layer. The results show that amperometric response values were greater for the polymer containing more hydrazine ends than the polymer containing more carbazole groups. This is due to the that as the hydrazine ends increased, the more enzyme crosslinker groups at the same surface size. The evaluation of two different configurations (pTECA/GOx and pCTDA/GOx) of working electrodes suggested that the pTECA/GOx configuration, which was composed of more hydrazine ends and enzyme, is the more suitable candidate for biosensor applications. Moreover, it was determined that the pTECA/GOx and pCTDA/GOx-based electrodes are reliable for the establishment of advanced electron transfer between enzyme and electrode for the application in amperometric biosensors because of the observed high amperometric response values, and low LOD values.
Journal of the Brazilian Chemical Society, 2001
Neste trabalho é apresentada a co-imobilização de GOx e ferroceno numa matriz polimérica através de um método simples de uma etapa. Esse procedimento para a imobilização de ferroceno como mediador da reação enzimática não envolve a modificação do monômero ou da enzima, o que poderia levar à perda de sua atividade. A incorporação de ferroceno se traduz no incremento da sensibilidade, comparado ao sensor sem mediador redox (1,5 vs 0,23 µA mmol-1 L cm-2) e diminuição do potencial de trabalho até 0,4 V. O sensor desenvolvido mostra resposta linear até 10 mmol L-1 e um tempo de resposta de 2 s, além de razoável estabilidade depois de uma semana de uso. The co-immobilization of GOx and ferrocene in a polymeric matrix by a one-step simple method is presented. This procedure to immobilize ferrocene as mediator implies the absence of modification of the monomer or the enzyme that would lead to the loss of its activity. Ferrocene incorporation results in an increase of sensitivity compared with the sensor prepared without the redox mediator (1.5 vs 0.23 µA mmol-1 L cm-2) and the decrease of the working potential to 0.4 V. The prepared sensor shows linear response till 10 mmol L-1 and response time of 2 s, in addition to reasonable stability after one week.
Journal of The Electrochemical Society, 2018
A new approach was developed using a combination of a conducting polymer; poly(3,4-ethylenedioxythiophene) (PEDOT) with the electrochemically produced polymer of N-ferrocenyl-3-(1H-pyrrol-1-yl)aniline, (PFcPyBz) layer for the enzyme scaffolding resulting in excellent analytical parameters. To organize such a surface, graphite electrode was coated with a PEDOT layer and it was used as a transducer for electrochemical deposition of the polymer of a newly synthesized FcPyBz monomer. Using a PEDOT layer as the working electrode improved localization of the PFcPyBz on the transducer surface while enhancing the biosensor performance. A simple binding of glucose oxidase (GOx) as a test enzyme on this new polymeric platform was achieved using glutaraldehyde (GA) as the cross linker. The low limit of detection and high sensing sensitivity on glucose for the biosensor are estimated as 54 μM and 112.2 μA/mMcm 2 , respectively. The surface characterizations of the modified electrodes were investigated by cyclic voltammetry (CV), attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. Finally, different kinds of beverages were tested for sensor reliability with high accuracy. A well-known disorder, diabetes mellitus occurs via an increase in glucose concentration in human blood. Since it is spreading worldwide , its careful and precise detection gained importance to reduce the threat. 1,2 Mirroring the importance of the disease is the worldwide interest leading to publishing a number of articles per year. These developments have opened ways to the wide array of emerging applications in glucose biosensors. Development of the glucose oxidase based enzyme biosensors by different immobilization techniques on various kind of electrodes had been studied for several decades. 3,4 Conjugated polymers (CPs) promise to advance a number of real-world technologies. Of these applications, they are particularly attractive for uses in enzyme biosensors for environmental and health monitoring. Their unique properties such as high electrical conductivity, ease of preparation and good environmental and chemical stability have motivated the use of CPs in the form of thin films for biosensors. 5,6 CP based biosensors bring simple, accurate, reliable and low-cost determination of various analytes and act as a very effective analytical tool in the multiple areas. This description is also supported by a number of researchers using the CPs as an immobilization architecture. 7-10 PEDOT has been reported to exhibit superior stability in conductivity compared to other available polymers and this property prompted us to use the PEDOT film as a transducer in order to obtain a more stable scaffolding for the glucose sensor. Brett and co-workers developed a PEDOT/poly (methylene blue) (PMB) modified glassy carbon electrode (GCE) for a GOx-based biosensor. 11 PEDOT films generated on top of PMB modified bare electrode was used to enhance the stability of PMB modified electrode. The proposed sensing architecture (GOx/PEDOT/PMB/GCE) showed better biosensor performance than the ones for GOx/GCE and GOx/PEDOT/GCE biosensors. In another work, Si reported a simple synthesis of a hybrid film by elec-tropolymerizing 3,4-ethylenedioxythiophene (EDOT) on nanoporous gold (NPG) for applications in amperometric glucose biosensors. 12 They finally concluded that the NPG/PEDOT/GOx biosensor prepared by optimum film thickness is appropriate for effective substrate diffusing. PEDOT is also used as the working electrode for glucose sensing by Ho and co-workers. 13 In this work, PEDOT and ferrocene (Fc) containing polymer were used for not only reducing the working potential but also for improving the stability of the sensor. Moreover, after the invention of the Fc molecule in 1951, scientist paid attention to this sandwich like molecule in many other research areas. 14,15 A huge number of molecules containing Fc moiety were designed and assessed for their possible use in glucose sensing applications. 16,17 Elec-trodeposited copolymer of pyrrole and ferrocene carboxylate modified pyrrole p(Py-FcPy), 18 co-deposition of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl) aniline (SNS-NH 2) and 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl) amidoferrocenyldithiophosphonate (SNS-NH2-Fc) 19 and copolymer of O-4-(1H-pyrrol-1-yl)-ferrocenyldithiophosphonate (TPFc) with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)butane-1-amine (TPA) 20 are the examples of the conjugated polymer based electron-mediating support materials for developing GOx immobilized electrodes. Under the light of this, this work will show a significant way to create CPs-based glucose biosensors exhibiting selective responses to a target analyte. Such approach predominantly includes functional-ization of PEDOT bearing surface with newly synthesized Fc moiety containing polymer. In this report, for the first time a PEDOT transducer was designed and a new one-pot synthesized ferrocene containing monomer was electrochemically deposited on a well-known polymer (PEDOT) surface for glucose sensing. Without the PEDOT layer it was difficult to coat PFcPyBz layer on the bare graphite surface. For this reason, the electrode surface is first modified with PEDOT and then coated with PFcPyBz. We described the importance and effect of CPs in biosensor construction that was highlighted in our previous works. 21,22 However, need for a promising analytical devices for glucose sensing with high accuracy and sensitivity has motivated us to design a new sensing system. Designing of the new surface in this study, a highly sensitive and reliable glucose sensor was developed with the help of glucose oxidase (GOx), as a model enzyme. Detailed optimization studies, surface characterization of the polymer layers and the amperomet-ric characterization were performed. Additionally, the testing of the biosensor was conducted using different kinds of commercial beverages. Experimental Chemicals and instrumentation.-All chemicals which were used for monomer synthesis and electrochemical polymerization, were purchased from Aldrich and used without further purification. Materials used for biosensor construction were also obtained from Aldrich. Glucose oxidase enzyme used in this study was (GOx, β-D-glucose: oxygen 1-oxidoreductase, EC 1.1.3.4, 17300 units/g solid) from A. Niger. Electrochemical polymerizations of the EDOT and the FcPyBz) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 144.122.34.94 Downloaded on 2018-12-27 to IP
Polymers
Biosensors for the determination of glucose concentration have a great significance in clinical diagnosis, and in the food and pharmaceutics industries. In this research, short-chain polyaniline (PANI) and polypyrrole (Ppy)-based nanocomposites with glucose oxidase (GOx) and 6 nm diameter AuNPs (AuNPs(6 nm)) were deposited on the graphite rod (GR) electrode followed by the immobilization of GOx. Optimal conditions for the modification of GR electrodes by conducting polymer-based nanocomposites and GOx were elaborated. The electrodes were investigated by cyclic voltammetry and constant potential amperometry in the presence of the redox mediator phenazine methosulfate (PMS). The improved enzymatic biosensors based on GR/PANI-AuNPs(6 nm)-GOx/GOx and GR/Ppy-AuNPs(6 nm)-GOx/GOx electrodes were characterized by high sensitivity (65.4 and 55.4 μA mM−1 cm−2), low limit of detection (0.070 and 0.071 mmol L−1), wide linear range (up to 16.5 mmol L−1), good repeatability (RSD 4.67 and 5.89%), ...
Journal of Electroanalytical Chemistry, 2001
We have constructed and characterised a glucose sensor using glucose oxidase (GOD) covalently attached to carboxylic acid polyethyleneglycol (PEG), called (PEG–GOD). This modified enzyme was entrapped afterwards within poly(3,4-ethylenedioxythiophene) (PEDT) films electrogenerated on glassy carbon (GC) electrodes. The composite (PEG–GOD/PEDT) film is more porous than the film without enzyme (PEDT+PEG). Data from electrochemical quartz microbalance (ECQM) and pH-stat experiments indicate a good relative activity of the modified enzyme, ca. 12–15%. Amperometric measurements, using ferrocenemethanol as the redox mediator, confirms that the modified enzyme is catalytically active. The effect of film thickness was also investigated. The sensitivities were quite similar for modified-GOD electrodes (ca. 3 mA cm−2 M−1) and unmodified-GOD electrodes (ca. 2.7 mA cm−2 M−1) but a better stability was obtained with modified PEG–GOD electrodes.