Electrochemically induced deposition of poly(benzoxazine) precursors as immobilization matrix for enzymes (original) (raw)
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Electroanalysis, 2015
B enzoxazine oligomers synthesizedb yaMannich type reactiono fb isphenolA ,t etraethylenepentamine and formaldehydew ere electrochemically crosslinked in presence of both an Os-complex modified poly-(methacrylate) polymer and glucose oxidase. Thec rosslinking led to the formation of ab iocatalytically active layer on an electrode surface exhibiting aswellingp rocess afteri mmersion in an electrolyte solution containing glucose most likely due to the local decreaseo ft he pH value upon glucose oxidation. Optimization of the poly(benzoxazine) to Os-complex modified poly(methacrylate) ratio wasp erformed leading to ar eagentless glucose biosensor with improved stability.
Colloids and Surfaces B: Biointerfaces, 2013
In order to construct a robust covalent binding between biomolecule and immobilization platform in biosensor preparation, a novel functional monomer 4-(4,7-di(thiophen-2-yl)-1Hbenzo[d]imidazol-2-yl)benzaldehyde (BIBA) was designed and successfully synthesized. A c c e p t e d M a n u s c r i p t After electropolymerization of this monomer, electrochemical and spectroelectrochemical properties were investigated in detail. To fabricate the desired biosensor, glucose oxidase (GOx) was immobilized as a model enzyme on the polymer coated graphite electrode with the help of glutaraldehyde (GA). During the immobilization step, an imine bond was formed between the free amino groups of enzyme and aldehyde group of polymer. The surface characterization and morphology were investigated to confirm bioconjugation by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) at each step of biosensor fabrication. The optimized biosensor shows good linearity between 0.02 mM and 1.20 mM and a low limit of detection (LOD) of 2.29 M. Kinetic parameters K m app and I max were determined as 0.94 mM and 10.91 respectively. The biosensor was tested for human blood serum samples.
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.
Macromolecular Bioscience, 2010
A recently synthesized conducting polymer [poly(2-dodecyl-4,7-di(thiophen-2-yl)-2H-benzo [d][1,2,3]triazole (PTBT)] was tested as a platform for biomolecule immobilization. After electrochemical polymerization of the monomer (TBT) on graphite electrodes, immobilization of glucose oxidase (GOx, b-D-glucose: oxygen-1-oxidoreductase, EC 1.1.3.4) was carried out. To improve the interactions between the enzyme and hydrophobic alkyl chain on the polymeric structure, GOx and isoleucine (Ile) amino acid were mixed in sodium phosphate buffer (pH 7.0) with a high ionic strength (250 Â 10 À3 M). The solution is then casted on the polymer film, and the amino groups in the protein structure were crosslinked using glutaraldehyde (GA) as the bifunctional agent. Finally, the surface was covered with a perm-selective membrane. Consequently, cross-linked enzyme crystal (CLEC) like assembles with regular shapes were observed after immobilization. Microscopic techniques such as scanning electron microscopy (SEM) and fluorescence microscopy were used to monitor the surface morphologies of both the polymer and the bioactive layer. Electrochemical responses of the enzyme electrodes were measured by monitoring O 2 consumption in the presence of glucose at -0.7 V. The optimized biosensor showed a very good linearity between 0.05 and 2.5 Â 10 À3 M with a 52 s response time and a detection limit (LOD) of 0.029 Â 10 À3 M to glucose. Also, kinetic parameters, operational and storage stabilities were determined. K m and I max values were found as 4.6 Â 10 À3 M and 2.49 mA, respectively. It was also shown that no activity was lost during operational and storage conditions. Finally, proposed system was applied for glucose biomonitoring during fermentation in yeast culture where HPLC was used as the reference method to verify the data obtained by the proposed biosensor.
Conducting polymers with benzothiadiazole and benzoselenadiazole units for biosensor applications
Sensors and Actuators B: Chemical, 2011
Poly(4,7-di(2,3)-dihydrothienol [3,4-b][1,4]dioxin-5-yl-benzo[1,2,5]thiadiazole) (PBDT) and poly(4,7di(2,3)-dihydrothienol [3,4-b][1,4]dioxin-5-yl-2,1,3-benzoselenadiazole) (PESeE) were electrochemically deposited on graphite electrodes and used as immobilization matrices for biosensing studies. After electrochemical deposition of the polymeric matrices, glucose oxidase (GOx) was immobilized on the modified electrodes as the model enzyme. In the biosensing studies, the decrease in oxygen level as a result of enzymatic reaction was monitored at −0.7 V vs Ag/AgCl (3.0 M KCl) and correlated with substrate concentration. The biosensor was characterized in terms of several parameters such as operational and storage stabilities, kinetic parameters (K m and I max ) and surface morphologies. The biosensor was tested on real human blood serum samples.
Electrodeposited polytyramine as an immobilisation matrix for enzyme biosensors
Biosensors and Bioelectronics, 1998
The application of an electrodeposited polytyramine film as an immobilisation matrix for the construction of enzyme biosensors is described. Glucose oxidase (used as a model enzyme) is covalently attached to free amine groups on the polytyramine film using the coupling reagents 1-ethyl-3(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide. The resultant recognition interface consisted of multilayers of GOx immobilised onto the polymer surface. This method of constructing enzyme biosensors is shown to produce a highly reproducible and stable device. The biosensor showed no loss in electrode response after four months of dry storage and exhibited only minor loss in response after 20 days of repeated use. The resultant biosensor had a linear range of 0.1-28 mM glucose and a detection limit of 0.01 mM.
Sensors, 2012
Different classes of polymeric materials such as nanomaterials, sol-gel materials, conducting polymers, functional polymers and biomaterials have been used in the design of sensors and biosensors. Various methods have been used, for example from direct adsorption, covalent bonding, crossing-linking with glutaraldehyde on composites to mixing the enzymes or use of functionalized beads for the design of sensors and biosensors using these polymeric materials in recent years. It is widely acknowledged that analytical sensing at electrodes modified with polymeric materials results in low detection limits, high sensitivities, lower applied potential, good stability, efficient electron transfer and easier immobilization of enzymes on electrodes such that sensing and biosensing of environmental pollutants is made easier. However, there are a number of challenges to be addressed in order to fulfill the applications of polymeric based polymers such as cost and shortening the long laboratory synthetic pathways involved in sensor preparation. Furthermore, the toxicological effects on flora and fauna of some of these polymeric materials have not been well studied. Given these disadvantages, efforts are now geared towards introducing low cost biomaterials that can serve as alternatives for the development of novel electrochemical sensors and biosensors. This review highlights recent contributions in the development of the electrochemical sensors and biosensors based on
Synthetic Metals, 2015
ABSTRACT Development of materials composed of polymer–clay nanocomposites (PCN) and conducting polymers attracts great interest and preferred in various applications. Hereby, polymethylmethacrylate (PMMA) layered silicate nanocomposites were prepared by in-situ suspension polymerization by grafting PMMA with laponite using a suitable grafting agent. The properties of the as-synthesized PCN materials are characterized by differential scanning calorimetry (DSC), thermal gravimetry analysis (TGA) and gel permeation chromatography (GPC). A conducting polymer; poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-7-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)-2-benzyl-1H-benzo[d]imidazole) (poly(BIPE)) and a PMMA–clay nanocomposite with 2-(methacryloyloxy) ethyltrimethylammonium chloride (MTMA) modifier were examined as a platform for biomolecule deposition. Glucose oxidase (GOx, β-d-glucose: oxygen-1-oxidoreductase, EC 1.1.3.4) was chosen as the model enzyme to prepare a scaffold for glucose sensing. Three different sensing strategies; PCN/GOx, poly(BIPE)/GOx and PCN/poly(BIPE)/GOx were analyzed and their biosensor performances were discussed. Surface morphology of the modified electrodes was characterized by scanning electron microscopy (SEM) technique. Electrochemical responses of the enzyme electrodes were monitored at −0.7 V vs. Ag reference electrode by monitoring oxygen consumption in the presence of glucose. After optimum conditions were determined, kinetic and analytical parameters; KMapp, Imax, LOD and sensitivity were investigated for each sensing platform.
Colloids and Surfaces B: Biointerfaces, 2018
Since conjugated polymers are an important class of materials with remarkable properties in biosensor applications, in this study, a novel glucose biosensor based on a conjugated polymer was fabricated via the electropolymerization of the monomer 10,13-bis(4-hexylthiophen-2-yl)dipyridol[3,2-a:2 ,3-c]phenazine onto a graphite electrode surface. Glucose oxidase (GOx) was used as the model biological recognition element. As a result of the enzymatic reaction between GOx and glucose, the glucose amount was determined by monitoring the change in the oxygen level associated with substrate concentration via the amperometric detection technique. The proposed system possessed superior properties with K M app value of 0.262 mM, 2.88 × 10 −3 mM limit of detection and 105.12 A mM −1 cm −2 sensitivity. These results show that conjugated polymer film provides an effective and stable immobilization matrix for the enzyme. Finally, the biosensor was applied successfully to several commercially available beverage samples for glucose determination proving an inexpensive and highly sensitive system applicable for real time analyses.
Electropolymerization of 4-aminobenzoic acid (4-ABA) on graphite electrodes (GEs) was investigated for the development of electrochemically functionalized platforms applied to the immobilization of biomolecules. The electrogeneration of 4-ABA was carried out in perchloric acid solutions using cyclic voltammetry (CV) and chro-noamperometry (CA) techniques. In the case of CV studies, the GEs were modified by applying 100 consecutive potential cycles, while, in the case of CA studies, the electrodes were modified at different potentials (E/V vs. Ag/AgCl): 0.95, 1.05, and 1.15. The modified GEs were characterized in HClO 4 solutions in the presence and absence of the ferricyanide/ferrocyanide redox couple (redox probe) using the CV and electrochemical impedance spectroscopy techniques. Scanning electron microscopy was used for morphological characterization. In the case of CA, the best electrochemical activities for the electropo-lymerization reaction are in the following order of performance: 1.05 [ 1.15 [ 0.95 V. The poly(4-ABA) platforms were investigated for the immobilization and direct detection of purine bases (adenine and guanine), where higher values of the anodic peak current (I p,a) were observed for the transducers electroformed using CV. In the case of immobilization of poly(GA) oligonucleotides, as well as for the recognition of the hybridization event with the complementary target poly(CT), methylene blue (MB) and ethidium bromide (EB) were used as the indicator and intercalator, respectively. MB was reduced at-0.26 V resulting in the cathodic peak current (I p,c) for the ssDNA, while EB was oxidized at ?0.58 V yielding the higher anodic peak current (I p,a) for the dsDNA. The platforms were also evaluated for immobilization of the DD K peptide, with the antibacterial activity and biological recognition being verified using the complementary (phospholipid 1-palmitoyl-2-oleoyl phosphatidylcholine— POPC) and noncomplementary (phospholipid POPC ? cholesterol) targets. The recognition mechanism was monitored from impedance measurements, with a good interaction of the DD K peptide with the POPC mimetic membrane being verified. In addition, the interaction was affected by the presence of cholesterol, revealing that the use of poly(4-ABA) platforms is very promising for the development of biosensors.