Screen-Printed Electrodes Modified with Glucose Oxidase Immobilized in Hybrid Organosilicon Sol-Gel Matrix (original) (raw)
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formerly Philippine Agriculturist, 2007
(English) Amperometric biosensors for bonded glucose were fabricated using screen printed carbon elecrode bulk modified with manganese dioxide onto which glucosidase and glucose oxidase were immobilized by Nafion film entrapment. Three methods of enzyme immobilization were performed (layering, mixing and sequencing of enzyme solutions). The analytical performance of the biosensor prepared by different enzyme immobilization methods was assessed in a flow injection mode using three sugar ...
Application of sol gel technique for glucose oxidase immobilization in biosensor application
A sol gel based biosensor using 3-glycidoxypropyl dimethylethoxysilane, as a silane agent was developed as a novel method for biosensor enzyme immobilization. The key materials applied were tetra methyl orthosilicate (TMOS), and the cross link agent, 3-Glycidoxypropyl dimethylethoxysilane, (GDP). Three compositions with different amount of GDP and glucose oxidase were experimented with the amount of TMOS was kept constant. The first coating consisted of 2mg of glucose oxidase and 20μl of GDP. The second trial involved higher GDP composition which is 100μl. The final trial applied higher content of glucose oxidase which is 12 mg with 20μl of GDP. The result showed that sensors with high composition of crosslink agent coating was capable to exhibit reliable glucose detection. The crosslink agent insufficiency in the first composition failed to provide good attachment for the enzyme on the electrode. Thus, the test was halted after few readings due to the inability of the sensor to detect glucose increment. For the high amount glucose oxidase composition, failure happened due to the deficiency of GDP to retain the enzyme thus contributed to the glucose oxidase leaching. We conclude that adequate amount of crosslink agent is vital for a sol gel based biosensor to function successfully.
Food Analytical Methods, 2013
In this study, we report the construction of amperometric screen-printed glucose biosensors for food analysis by using two procedures for Prussian Blue (PB) deposition and different membranes for enzymatic immobilisation. The comparison between the screen-printed electrodes modified with PB by electrochemical and chemical deposition showed higher analytical performance (detection limit of 1 μM, linear range from 0.5 to 500 μM and a sensitivity of 823 μA mM −1 cm −2) when the latter was employed. Then, the immobilisation of glucose oxidase (GOD) by silica sol-gel and polyvinyl alcohol (PVA) hydrogel was performed on electrochemically modified PB electrodes. The electrochemical response of two glucose biosensors was evaluated by flow injection analysis. Biosensors constructed by silica sol-gel entrapment showed a wider linear range (0.005-1 mM) and a detection limit (0.02 mM) that was 10-fold lower than using entrapped GOD in PVA. The selected glucose biosensor showed negligible interference from ascorbic acid when the Nafion membrane was used to cover the PB-modified electrode surface. Additionally, it exhibited an operating lifetime of 8 h under continuous glucose injections ranging from 0.01 to 2 mM. Finally, the biosensor was applied for specific determination of glucose in red and white wines, juices and dried fruit.
Electrochemical Evaluation of the Properties of the Immobilized Enzyme Glucose Oxidase
ECS Transactions, 2008
The enzyme glucose oxidase was evaluated as a recognition element in electrochemical biosensors. Immobilization techniques as physical adsorption, entrapment in electrogenerated polymer film, affinity and covalent binding are discussed based in the involved physicochemical and kinetic phenomena. This includes the determination of the main kinetic parameters: apparent Michaelis-Menten constant K m app and maximal rate I max of the heterogeneous enzyme reactions of glucose oxidation in the absence and in the presence of inhibitors. Parameters as pH, optimal temperature and stability of the biocatalyst were established analyzing the transfer function of the developed amperometric glucose oxidase sensors of first and second generation I=I max [S] / (K m app + [S]).
Journal of the Chilean Chemical Society
In this study, an electrochemical biosensor was developed by using a sol-gel coating solution. The modified platinum electrode used in the study was constructed by immobilization of glucose oxidase under a layer of sol-gel film. The sol-gel coating solution was prepared by using GLYMO, TEOS, and MTEOS. Electrochemical measurements were carried out amperometrically by determining hydrogen peroxide produced by the enzymatic reaction between glucose and glucose oxidase. The amperometric responses of the resulting enzymatic electrode to glucose were rapid. It was observed that the amperometric response of the enzymatic electrode was linear for glucose concentrations in the range from 2 to18 mM with 50 s response time. LOD and LOQ for the enzymatic electrode were calculated to be 0.055 mM and 0.184 mM, respectively. It was determined that the developed biosensor had an acceptable reproducibility. The selectivity of the biosensor was determined in the presence of some interfering substanc...
2020
In this study, we report the construction of amperometric screen-printed glucose biosensors for food analysis by using two procedures for Prussian Blue (PB) deposition and different membranes for enzymatic immobilisation. The comparison between the screen-printed electrodes modified with PB by electrochemical and chemical deposition showed higher analytical performance (detection limit of 1 μM, linear range from 0.5 to 500 μM and a sensitivity of 823 μA mM −1 cm −2 ) when the latter was employed. Then, the immobilisation of glucose oxidase (GOD) by silica sol-gel and polyvinyl alcohol (PVA) hydrogel was performed on electrochemically modified PB electrodes. The electrochemical response of two glucose biosensors was evaluated by flow injection analysis. Biosensors constructed by silica sol-gel entrapment showed a wider linear range (0.005-1 mM) and a detection limit (0.02 mM) that was 10-fold lower than using entrapped GOD in PVA. The selected glucose biosensor showed negligible inte...
Analytical Sciences, 2019
The characteristics of an electrochemical biosensor based on a Prussian-blue screen-printed electrode containing glucose oxidase incorporated into polyelectrolyte microcapsules (PMC) are considered. PMC with the embedded enzyme were formed using sodium polystyrene sulfonate and poly(allylamine hydrochloride). The characteristics were compared with those of the enzyme immobilized in chitosan gel. We assessed the dependences of biosensor signals on the composition of the buffer solution, on the glucose concentration; the operational and long-term stabilities. The enzyme immobilized in PMC proved to be more sensitive to buffer molarity at a maximum within 35-40 mM. The apparent Michaelis constants were 1.5 and 4.1 mM at the immobilization in, respectively, chitosan and PMC. The developed biosensors were used to assay commercial juices. The biosensors' data on the glucose contents were shown to have a high correlation with the standard spectrophotometric assay (0.92-0.95%), which implies a possible application of the fabricated biosensors in foodstuff analysis.
Biosensing approach for alcohol determination using immobilized alcohol oxidase
Biosensors and Bioelectronics, 2006
Alcohol oxidase (AOD) was immobilized in polypyrrole (PPy) and a random copolymer containing 3-methylthienyl methacrylate and pvinylbenzyloxy poly(ethyleneoxide) matrices. Immobilization of enzyme was performed via entrapment in conducting polymers during electrochemical polymerization of pyrrole through the thiophene moiety of the copolymer. Three different alcohols, namely methanol, ethanol and n-propanol, were used as substrates. Maximum reaction rates, Michaelis-Menten constants, optimum temperature and pH values, operational stabilities and shelf life of the enzyme electrodes were investigated.
Sensors and Actuators B: Chemical, 1996
The feasibility of an amperometric glucose biosensor based on immobilization of glucose oxidase (GOD) in inorganic gels (laponite) is investigated. The gels modified with enzyme were deposited onto platinum electrodes and then were exposed to glutaraldehyde vapor. The effects of different parameters (glutaraldehyde crosslinking and time of drying) on the performances of the biosensor have been studied. For optimum conditions, remarkably good characteristics were obtained: larger dynamic range (0.1--4 mM of glucose), higher/max, higher sensitivity (threefold better than this obtained through immobilization of enzymes in laponite films). The main advantage of the biosensor reported here is its long stability. The biosensor was kept for several weeks in a buffer solution at 4°C. About 450 measurements were done without any loss of the linearity in the range (0.1-4 mM). The possibility of an increase in the amount of enzyme in the biofilm which has been demonstrated, allows us to obtain more sensitive devices. geywords: Biosensor; Glucose oxidase; Inorganic gels; Laponite; High sensitivity; Long term stability 0925-4005/96/$15.00
Biosensors and Bioelectronics, 2004
Glucose oxidase (GOD) was immobilized on screen-printed platinum electrodes by entrapment in a screen printable paste polymerized by irradiation with UV-light. The influences of different additives, in particular polymers and graphite, on the sensitivity and stability of the sensor and the permeability of the enzyme layer for a possible electrochemical interferent were investigated. The chosen additives were Gafquat 755N, poly-l-lysine, bovine serum albumin (BSA), sodium dodecylsulfate (SDS), polyethylene glycol (PEG), Nafion and graphite. All additives led to increases of glucose signals, i.e. improved the sensitivity of glucose detection with Gafquat 755N, poly-l-lysine, SDS and graphite showing the strongest influences with increases by a factor 4, 6.5, 5 and 10, respectively. Ascorbic acid was used as a model interferent showing the influence of the enzyme layer composition on the selectivity of the sensor. The addition of Gafquat 755N or poly-l-lysine led to higher signals not only for glucose, but also for ascorbic acid. SDS addition already reduced the influence of ascorbic acid, which was almost completely eliminated when Nafion (5%) and PEG (10%) were added. A comparable beneficial effect on the selectivity of the sensors was also observed for the addition of 0.5% graphite. Thus, the enzyme electrodes with PEG, Nafion or graphite as additives in the enzyme layer were applied to glucose determinations in food samples and samples obtained from E. coli cultivations. the co-factor flavin-adenine dinucleotide (FAD) is reduced to FADH 2 , followed by the re-oxidation of the co-factor by molecular oxygen producing hydrogen peroxide while glucono-␦-lactone is hydrolysed in aqueous media to gluconic acid according to the following three reaction steps: