Enzyme amperometric

E. Zilkha, T.P. Obrenovitch, A. Koshy, H. Kusakabe, and H.P. Bennetto, Extracellular glutamate online monitoring using microdialysis coupled to enzyme-amperometric analysis. J. Neurosci. Methods. 60,1-9 (1995). 

Prostate specific Sandwich or enzyme- Amperometric, dissociation of... 

Biotinylated probe, then DPV oxidation of accumulated cationic product of substrate hydrolysis by ALP enzyme Amperometric detection of catalytically oxidised DNA... 

Glucose oxidase EC 1.1.3.4 yeast h2o2 C/wired enzyme amperometric 22... 

Marty JL and Noguer T. 1993. Bi-enzyme amperometric sensor for the detection of dithiocarbamate fungicides. Analusis 21 231-233. 

Cluistian N et al (2012) Implantable enzyme amperometric biosensors. Biosens Bioelectron 35 14—26... 

Yuqing M, Jianrong C, Xiaohua W (2004) Using electropolymerized non-conducting polymers to develop enzyme amperometric biosensors. Trends Biotechnol 22(5) 227-231... 

Yang, X. and G. A. Rechnitz. 1995. Dual enzyme amperometric biosensor for putrescine with interference suppression. Electroanalysis 2 105-108. 

Gouda MD, Thakur MS, Karanth NG (1997) A dual enzyme amperometric biosensor for monitoring organophosphate pesticide. Biotech Tech 11 653-655... 

Figure 11.39 summarizes the reactions taking place in this amperometric sensor. FAD is the oxidized form of flavin adenine nucleotide (the active site of the enzyme glucose oxidase), and FAD1T2 is the active site s reduced form. Note that O2 serves as a mediator, carrying electrons to the electrode. Other mediators, such as Fe(CN)6 , can be used in place of O2. 

By changing the enzyme and mediator, the amperometric sensor in Figure 11.39 is easily extended to the analysis of other substrates. Other bioselective materials may be incorporated into amperometric sensors. For example, a CO2 sensor has been developed using an amperometric O2 sensor with a two-layer membrane, one of which contains an immobilized preparation of autotrophic bacteria. As CO2 diffuses through the membranes, it is converted to O2 by the bacteria, increasing the concentration of O2 at the Pt cathode. 

This experiment describes the use of a commercially available amperometric biosensor for glucose that utilizes the enzyme glucose oxidase. The concentration of glucose in artificial... 

Commercially available kits for monitoring blood-glucose use an amperometric biosensor incorporating the enzyme glucose oxidase. This experiment describes how such monitors can be adapted to the quantitative analysis of glucose in beverages. 

Abass and colleagues developed an amperometric biosensor for NHA that uses the enzyme glutamate dehydrogenase to catalyze the following reaction. 

AN AMPEROMETRIC ENZYME IMMUNOSENSOR BASED ON SCREEN-PRINTED ELECTRODE FOR THE DETERMINATION OF KLEBSIELLA PNEUMONIAE BACTERIAL ANTIGEN... 

The aim of our investigation was the development of the amperometric enzyme immunosensor for the determination of Klebsiella pneumoniae bacterial antigen (Ag), causes the different inflammatory diseases. The biosensing pail of the sensors consisted of the enzyme (cholinesterase) and antibodies (Ab) immobilized on the working surface of the screen-printed electrode. Bovine seiaim albumin was used as a matrix component. 

The developed amperometric enzyme immunosensor was probed to determine the Klebsiella pneumoniae antigen in the human sera samples. The obtained results were juxtaposed with the data of the bacteriological analysis. 

FIGURE 3-21 Typical amperometric readout during automated flow injection assays of ethanol at an enzyme carbon-paste electrode. Peaks a through h 2 x 10 5 M to 1.6 x 10 4 M ethanol. 

Instead of immobilizing the antibody onto the transducer, it is possible to use a bare (amperometric or potentiometric) electrode for probing enzyme immunoassay reactions (42). In this case, the content of the immunoassay reaction vessel is injected to an appropriate flow system containing an electrochemical detector, or the electrode can be inserted into the reaction vessel. Remarkably low (femtomolar) detection limits have been reported in connection with the use of the alkaline phosphatase label (43,44). This enzyme catalyzes the hydrolysis of phosphate esters to liberate easily oxidizable phenolic products. 

Enzyme linked electrochemical techniques can be carried out in two basic manners. In the first approach the enzyme is immobilized at the electrode. A second approach is to use a hydrodynamic technique, such as flow injection analysis (FIAEC) or liquid chromatography (LCEC), with the enzyme reaction being either off-line or on-line in a reactor prior to the amperometric detector. Hydrodynamic techniques provide a convenient and efficient method for transporting and mixing the substrate and enzyme, subsequent transport of product to the electrode, and rapid sample turnaround. The kinetics of the enzyme system can also be readily studied using hydrodynamic techniques. Immobilizing the enzyme at the electrode provides a simple system which is amenable to in vivo analysis. 

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