Immobilized enzymes, biosensors

Immobilized catalases, for textile bleaching effluent treatment, 4 68—69 Immobilized cells, 3 670 Immobilized enzyme biosensors,... 

Gordon RK, Doctor BP. Immobilized enzymes biosensors for chemical toxins. US Patent Trade Office 6,406,876, 2002 18 June,... 

Enzymatic bioreactor Immobilized enzyme biosensor Immobilized enzyme reactor Immobilized microfluidic enzyme reactor (IMER) Membrane reactor... 

Situmorang, M., D.B. Hibbert, and J.J. Gooding. 2000. An experimental design study of interferences of clinical relevance of a polytyramine immobilized-enzyme biosensor. Electroanalysis 12 (2) 111. 

Microfluidic bioreactors have also been widely used to make immobilized enzyme biosensors. In this application the bioreactor is applied as a part of a detection device for a biologically important analyte. For instance, glucose can be detected by having a bioreactor that contains glucose oxidase immobilized in a microfluidic system [9]. The enzyme enables detection of glucose by electrochemical detection of the products of the bioreactor. 

Immobilized enzyme biosensors will allow both accurate spatial resolution of the measuranent area and reuse of enzymes, which are sometimes costly. In order to... 

An immobilized-enzyme biosensor employing a polymer-modified electrode is illustrated in Fig. 34.2. 

Fig. 34.2 Schematic diagram of an immobilized enzyme biosensor based on conducting electroactive polymer-modified electrode. S and P are the substrate and product species, respectively Eox/Ered and Mox/Mred are the enzyme and mediator redox couples, respectively and the constants and kv. are the enzyme-mediator and the enzyme-substrate specific rates. K, and D, are the partition and diffusion coefficients of the /th species within the CEP membrane. (After Ref. 20.)...

The dye is excited by light suppHed through the optical fiber (see Fiber optics), and its fluorescence monitored, also via the optical fiber. Because molecular oxygen, O2, quenches the fluorescence of the dyes employed, the iatensity of the fluorescence is related to the concentration of O2 at the surface of the optical fiber. Any glucose present ia the test solution reduces the local O2 concentration because of the immobilized enzyme resulting ia an iacrease ia fluorescence iatensity. This biosensor has a detection limit for glucose of approximately 100 ]lM , response times are on the order of a miaute. 

Biocatalytic membrane electrodes have an ISE or a gas sensing electrode in contact with a thin layer of biocatalytic material, which can be an immobilized enzyme, bacterial particles or a tissue slice, as shown in Fig. 3 The biocatalyst converts substrate (the analyte) into product, which is measured by the electrode. Electrodes of this type are often referred to as biosensors . 

Enzyme electrodes belong to the family of biosensors. These also include systems with tissue sections or immobilized microorganism suspensions playing an analogous role as immobilized enzyme layers in enzyme electrodes. While the stability of enzyme electrode systems is the most difficult problem connected with their practical application, this is still more true with the bacteria and tissue electrodes. 

For application of protein-immobilized porous materials to sensor fields, use of an electroactive substance as the framework material is important. DeLouise and Miller demonstrated the immobilization of glutathione-S-transferase in electrochemically etched porous silicon films [134], which are attractive materials for the construction of biosensors and may also have utility for the production of immobilized enzyme bioreactors. Not limited to this case, practical applications of nanohybrids from biomolecules and mesoporous materials have been paid much attention. Examples of the application of such hybrids are summarized in a later section of this chapter. 

Fiber-optic biosensors based on luminescence and immobilized enzymes for the detection of NADH and ATP can be found in ref. (147-152). 

Gautier S.M., Blum L.J., Coulet P.R., Fiber-optic sensor with Co-immobilized bacterial bioluminescence enzymes, Biosensors 1989 4 181. 

Kuswandi B., Andres R., Narayanaswamy R., Optical fibre biosensors based on immobilized enzymes, Analyst 2001 126 1469-91. 

S. Sasso, R. Pierce, R. Walla, and A. Yacynych, Electropolymerized 1,2-diaminobenzene as a means to prevent interferences and fouling and to stabilize immobilized enzyme in electrochemical biosensors. Anal. Chem. 62, 1111-1117 (1990). 

The first enzyme biosensor was a glucose sensor reported by Clark in 1962 [194], This biosensor measured the product of glucose oxidation by GOD using an electrode which was a remarkable achievement even though the enzyme was not immobilized on the electrode. Updark and Hicks have developed an improved enzyme sensor using enzyme immobilization [194], The sensor combined the membrane-immobilized GOD with an oxygen electrode, and oxygen measurements were carried out before and after the enzyme reaction. Their report showed the importance of biomaterial immobilization to enhance the stability of a biosensor. 

A.L. Crumbliss, J.Z. Stonehuerner, R.W. Henkens, J. Zhao, and J.P. O Daly, A carrageenan hydrogel stabilized colloidal gold multi-enzyme biosensor electrode utilizing immobilized horseradish peroxidase and cholesterol oxidase/cholesterol esterase to detect cholesterol in serum and whole blood. Biosens. Bioelectron. 8, 331-337 (1993). 

Figure 3.8 — (A) Biosensors used in different FI manifolds to perform reaction-rate measurements (I) stopped-flow manifold (II) iterative flow-reversal system (III) open-closed configuration S sample B buffer P pump IV injection valve PC personal computer IMEC immobilized enzyme cell D detector W waste SV switching valve. (B) Types of recordings obtained by using the three types of biosensors and measurements to be performed on them in order to develop reaction-rate methods. (Reproduced from [50] with permission of Elsevier Science Publishers).

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