Conducting polymer glucose sensors

Figure 10.46 Time course of drain current at E = 35 mV vs. SCE Nsd -20 mV) for a PANI-PAA/PANI-bisulfite/GOx-PDAB nanojunction (20-60 nm) in 20fil Mclivaine buffer, 0.5 M Na2S04 pH 5 upon 1 pi successive additions of 40 mM glucose. (Reprinted with permission from Nano Letters, A Conducting Polymer Nanojunction Sensor for Glucose Detection by Erica S. Eorzani et al., 4, 9. Copyright (2004) American Chemical Society)...

E.S. Foizani, H. Zhang, L.A. Nagahara, I. Amlani, R. Tsui, N. Tao, A conducting polymer nanojunction sensor for glucose detection. Nano Letters 4 (2004) 1785-1788. 

M. K. Malmros, J. Gulbinski III, and W. B. Gibbs, A semi-conductive polymer film sensor for glucose. Biosensors 3 1 (1987/88). 

Entrapment of biochemically reactive molecules into conductive polymer substrates is being used to develop electrochemical biosensors (212). This has proven especially useful for the incorporation of enzymes that retain their specific chemical reactivity. Electropolymerization of pyrrole in an aqueous solution containing glucose oxidase (GO) leads to a polypyrrole in which the GO enzyme is co-deposited with the polymer. These polymer-entrapped GO electrodes have been used as glucose sensors. A direct relationship is seen between the electrode response and the glucose concentration in the solution which was analyzed with a typical measurement taking between 20 to 40 s. 

Apart from electron promoters a large number of electron mediators have long been investigated to make redox enzymes electrochemically active on the electrode surface. In the line of this research electron mediators such as ferrocene and its derivatives have successfully been incorporated into an enzyme sensor for glucose [3]. The mediator was easily accessible to both glucose oxidase and an electron tunnelling pathway could be formed within the enzyme molecule [4]. The present authors [5,6] and Lowe and Foulds [7] used a conducting polymer as a molecular wire to connect a redox enzyme molecule to the electrode surface. 

To summarize, the advent of redox-relay modified polymers, such as redox hydrogels, conducting polymers, or EDPs, enabled the development of biosensors that even made it to commercial applications such as implantable glucose sensors. In addition, this approach is now increasingly used for the development of biofuel cells. 

T Schalkhammer, E Mann-Buxbaum, F Pittner, G Urban. Electrochemical glucose sensors on permselevtive non-conducting substituted pyrrole polymers. Sensors Actuators B4 273-281, 1991. 

Foulds, N. C., Lowe, C. R., Enzyme Entrapment in Electrically Conducting Polymers. Immobilization of Glucose Oxidase in Polypyrrole and Its Application in Amperometric Glucose Sensors , J. Chem. Soc. Faraday Thins. 92 (1986) 1259-1264. 

N.C. Foulds and C.R. Lowe, Enzyme entrapment in electrically conducting polymers immobilization of glucose-oxidase in polypyrrole and its appheation in amperometric glucose sensors. J. Chem. Soc. Faraday Trans. 1, 82, 1259-1264 (1986). 

J. Liu, M. Agarwal, and K. Varahramyan, Glucose sensor based on organic thin film transistor using glucose oxidase and conducting polymer. Sens. Actuat. B Chem., 135(1), 195-199 (2008). 

Most studies on enzyme immobilization in electropolymerized films are based on pyrrole and its derivatives. Conductivity of the polymer film is known to be destroyed by The GOx-based glucose sensors produce H2O2 even... 

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