Glucose Enzyme Electrode Research Articles

Polymeric Membranes for Silicon Based (Bio)Sensors

During the last decade, chemical and biochemical sensor research has benefited from the availability of new technologies and materials. New embodiments of classical devices have resulted from the use of e.g., solid state technology for the realization of the transducers. In this paper we describe several examples of membrane deposition techniques used in connection with planar, silicon based electrochemical transducers. Casting and electrochemical deposition of glucose oxidase containing membranes are described for the fabrication of glucose enzyme electrodes. Photolithographic patterning of polyacrylamide hydrogel and of siloxane based gas permeable membrane is used for the realization of an amperometric oxygen sensor and an ISFET-based pCO2 device. The last example is that of a free-chlorine sensor for which the photolithographic patterning of the polyHEMA hydrogel layer is described.

Amperometric enzyme sensor for glucose based on graphite paste-modified electrodes.

Amperometric enzyme electrode for glucose is described based on the incorporation of glucose oxidase (GOD) into graphite paste modified with tetracyanoquinodimethane (TCNQ). The incorporated enzyme exhibits high activity and long-term stability over the earlier TCNQ-based glucose sensor (1). The sensor provides a linear response to glucose over a wide concentration range. The response time of the sensor is 15-50 sec, and the detection limit is 0.5 mM. Stable response to the substrate was obtained during a period of 35 d. Application of the sensor in the plasma analysis is reported.

Measurements of Diffusivity in an Immobilized Enzyme Electrode for Glucose

Measurements of Diffusivity in an Immobilized Enzyme Electrode for Glucose

Comparative study of first-, second- and third-generation amperometric glucose enzyme electrodes in continuous-flow analysis of undiluted whole blood

First-, second- and third-generation amperometric glucose enzyme electrodes were compared under flow-injection and steady-state conditions for the monitoring of undiluted whole blood. First-generation electrodes, based on the detection of hydrogen peroxide at a platinum electrode, are generally unsuitable because of the eventual poisoning of the electrode and because of their susceptibility to oxygen variation. Second-generation electrodes in which a mediator is used for the reoxidation of glucose oxidase are more suitable for the analysis of whole blood under both steady-state and flow-injection conditions. However, the choice of mediator is important. The best results with regard to linear range and stability were obtained with tetrathiafulvalene, whereas dimethylferrocene required considerable pretreatment before use. A third-generation electrode based on tetrathiafulvalene-tetracyanoquinodimethane where direct oxidation of glucose oxidase occurs also proved useful but showed lower stability and a smaller dynamic range compared with the second-generation devices. Flow-injection and steady-state studies were carried out using wall-jet cell geometry.

Glucose enzyme electrode preparation by the codeposition of platinum and glucose oxidase onto glassy carbon

AbstractA glucose enzyme electrode was fabricated by the simultaneous electrodeposition of enxyme and platinum particles onto a glassy carbon substrate. The electrode combines the electrocatalytic activity of platinum and the stability of glassy carbon. The application of the electrode in flow‐injection detection of glucose is shown. A wide linear range and good precision is possible.

A planar glucose enzyme electrode

The IC-compatible lift-off technique is applied for patterning enzymatic membranes on wafer level. They are used to complete planar three-electrode microelectrochemical cells. These final devices, based on amperometric H 2O 2 detection, are tested for the determination of glucose and the responses of different glucose electrodes are compared.

Glucose enzyme electrode with percutaneous interface which operates independently of dissolved oxygen.

An enzyme glucose electrode that operates even when no oxygen is dissolved in the glucose solution has been developed and its in vitro performance evaluated. The electrode has been designed to be used with a percutaneous interface for future in vivo use. Oxygen is supplied to the electrode from the atmosphere. The electrode is based on the conventional H2O2 detecting enzyme electrode, in which an Ag cylinder 4.5 mm in diameter and 16 mm in length is used as a cathode. A Pt wire 0.5 mm in diameter is fixed in the centre for an anode, and 0.5 micrograms of albumin-linked glucose oxidase is immobilised at the tip of the anode. A recess of 3.6 mm diameter and 5 mm depth is made at the top of the electrode, and a breathing orifice 0.8 mm in diameter is drilled along the axis of the electrode to link the recess to the atmosphere. A thin oxygen permeable silicone layer fills the recess, allowing oxygen in the atmosphere to be supplied to the enzyme through the silicone layer. The electrode has a linear response to glucose concentration at an electrode output current ranging from 0 to 20 nA even when the oxygen concentration of the glucose solution is zero. The use of polyurethane as a diffusion barrier to glucose limits the electrode output current at a glucose concentration of 500 mg dl-1 (27.8 mmol 1-1] to 20 nA. Therefore, the electrode can measure glucose concentrations up to 500 mg dl-1 (27.8 mmol 1(-1] with no oxygen dissolved in the glucose solution. The electrode with the percutaneous interface seems suitable for implantation in sites of low oxygen concentration such as subcutaneous tissues.

Platinum-dispersed Nafion film modified glassy carbon as an electrocatalytic surface for an amperometric glucose enzyme electrode

A Nafion film dispersed with platinum particles formed on a glassy carbon electrode combines the electrocatalytic activity of platinum with the background stability of glassy carbon. It serves as a selective and sensitive electrode surface for an amperometric glucose enzyme electrode. Details on the construction and the functional characteristics of the enzyme electrode are described. It is shown that the electrode is well suited to the determination of levels of glucose in blood by flow injection with amperometric detection.

Ferrocene-Mediated Enzyme Electrode for Glucose with the Use of Conducting Polymer Support

Abstract An amperometric glucose-sensing electrode has been constructed by immobilizing glucose oxidase and fine particles of ferrocene in a photo-crosslinked poly(vinyl alcohol) layer. The magnitude of the response of the ferrocene-mediated electrode to glucose (0.5–50 mmol dm−3) increases when polypyrrole, an electrically conducting polymer, is incorporated into the poly(vinyl alcohol) support.

Development of an On-line Glucose Sensor for Fermentation Monitoring

A dimethylferrocene-mediated enzyme electrode for glucose (Cass et al., 1984) was evaluated for application to microbial fermentation monitoring and control. The deficiencies revealed - insufficient stability, progressive increase in response time and progressive decrease in linear range - were investigated using electrochemical and radiochemical techniques. The enzyme immobilization was improved with a novel procedure using periodate-oxidized glucose oxidase and an alky lamine electrode coating. An in-situ probe and a computer-controlled analytical system were developed for fermentation monitoring. The glucose concentration of an Escherichia coli batch culture was successfully monitored on line using this analytical system.

Detection of ATP and creatine kinase using an enzyme electrode

An electrochemical method for the detection of ATP and creatine kinase (ATP:creatine N-phosphotransferase, EC 2.7.3.2) coupled through hexokinase to an amperometric glucose enzyme electrode is described. The assay can be used to monitor creatine kinase activity over the range 0.01–10 U ml −1 and forms the basis for the development of a single-use biosensor.

Glucose enzyme electrode with extended linearity: Application to undiluted blood measurements

An enzyme electrodes is described for glucose determination in unstirred, undiluted whole blood. The system comprises an H 2O 2-detecting electrode upon which is placed a membrane laminate incorporating glucose oxidase. The external membrane was pretreated with methyltrichlorosilane. The electrode response was linearly dependent on glucose concentration up to 50 mmol l −1 glucose, it had a decreased dependence on dissolved oxygen concentrations and gave response times of 30–90 s. Whole blood glucose measurements correlated well with a routine spectrophotometric method.

Improved Blood Compatibility at a Glucose Enzyme Electrode Used for Ejctraoorpokeal Monitoring

Abstract A glucose enzyme electrode based on glucose oxidase has been used in an extracorporeal flow system which allows standardization during monitoring. The detection limit for glucose was 0.02 mmol/l, and the linear range, which extended to 5 mmol/l glucose, allowed measurement of whole blood after dilution. Restandardization following whole blood exposure led to a loss of sensitivity which was attributed to coating of electrode membranes by blood constituents. The problem was largely overcome through use of silane-treated membranes and the operation of electrodes in a narrow channel flow cell.

Enzyme electrode for glucose based on the quinoprotein glucose dehydrogenase.

Glucose dehydrogenase (E.C. 1.1.99.17) has been used to produce an amperometric enzyme electrode for glucose. With phenazine ethosulphate as the electron mediator, a linear response for up to 0.8 mM glucose was obtained with response times of 3–5 min. 2,6-Dichlorophenolindophenol as mediator gave long (> 30 min) response times, but the measurement time was reduced to 30 s by monitoring the first-order differential of the response; the derivatised signal allowed temporal separation of the enzyme-mediated signal from electrochemical interference. Whole blood glucose measurements were correlated with a spectrophotometric method based on glucose oxidase (y= 0.84x + 0.67, r= 0.963, n= 36).

Model of a two-substrate enzyme electrode for glucose.

Dans cette electrode, les enzymes sont immobilisees a l'interieur d'une membrane attachee a un detecteur electrochimique de l'oxygene, cosubstrat de la reaction enzymatique. Le modele mathematique presente concerne les phenomenes de reaction et de diffusion ayant lieu a l'interieur de la membrane

Implanting the glucose enzyme electrode: problems, progress, and alternative solutions.

An implantable glucose sensor is needed before a reliable artificial pancreas can be realized. The principles and current status of one such device, the glucose enzyme electrode, is presented and discussed. While monitoring glucose this enzyme sensor consumes enough oxygen to become oxygen-limited. This problem has been solved by developing hydrophobic membranes that are more permeable to oxygen than to glucose. Two types of membranes with this property made from (1) cross-linked albumin and (2) sebacyl chloride (nylon) are described. Placing these membranes over the glucose enzyme electrode solves the problem of oxygen limitation. Furthermore, the addition of this type of membrane increases the linear response range of the electrode to glucose to include the entire clinical range of interest (0-400 mg/dl). Other problems in developing an implantable glucose sensor are discussed. Competing strategies to achieve an implantable artificial pancreas without using electronic or mechanical components are presented and evaluated.

Amperometric Detection of Glucose Released from Imune Lysis of Glusoce Loaded Liposome

Abstract Glucose released from complement mediated immuno-specific damage of glucose loaded lipososmes sensitized with lipid antigens was detected by an amperometric glucose enzyme electrode in view of devising a simple method for electrochemical immunoassay. This method involves the indirect determinatio of antibody and complement levels by measurement of the relesed glucose. The results were correlated with those obtained by the prevous spectrophotometric method with excellent accuracy, indicating that the amperometric enzyme electrode can be another substitute for the previous spectrophotometric detectin of glucose released from immune lysis of liposme loaded with glucose.

Immobilized-enzyme rate-determination method for glucose analysis.

We present a rate-determination method for analyzing glucose. A glucose enzyme electrode serves as the sensor and is made by placing a gel-immobilized layer of glucose oxidase over the tip of a Clark-type O2 electrode. The electrode membrane is made of Teflon and is derivatized by etching with a suspension of colloidal sodium metal in organic solvent. The enzyme is coupled to the membrane surface by use of paraformaldehyde. The immobilized-enzyme method is compared with a similar solution-enzyme method and with the National Glucose Reference method. The immobilized enzyme method compares favorably with the solution-enzyme method and offers the advantages of simplicity, economy of enzyme, and linearity over a greater range of concentration.

Immobilized-enzyme rate-determination method for glucose analysis.

Abstract We present a rate-determination method for analyzing glucose. A glucose enzyme electrode serves as the sensor and is made by placing a gel-immobilized layer of glucose oxidase over the tip of a Clark-type O2 electrode. The electrode membrane is made of Teflon and is derivatized by etching with a suspension of colloidal sodium metal in organic solvent. The enzyme is coupled to the membrane surface by use of paraformaldehyde. The immobilized-enzyme method is compared with a similar solution-enzyme method and with the National Glucose Reference method. The immobilized enzyme method compares favorably with the solution-enzyme method and offers the advantages of simplicity, economy of enzyme, and linearity over a greater range of concentration.

Enzyme electrode for glucose based on an iodide membrane sensor

The construction of a new type of enzyme electrode for the potentiometric determination of glucose is reported. The electrode response is based on the enzymecatalyzed reactions: The highly selective iodide sensor monitors the local decrease in the iodide activity at the electrode surface. The properties of the above reactions were examined kinetically, with flow-stream techniques and potentiometric detection. The glucose electrode constructed and the use of flow-stream experiments with two iodide sensors provided accurate and convenient glucose determinations in the absence of some oxidizing and reducing agents.