Amperometric transduction

The amperometric transduction of an immunoreaction consists in the post-labeling of the detected target by an enzyme able to catalyze the production or the consumption of electroactive species. The electrochemical oxidation or reduction of the latter at a constant potential applied to the immunosensor provides thus a current, whose intensity is proportional to the amount of immobilized target. 

Amperometric Transduction of Optical Signals Recorded by Photoisomerizable Enzyme Electrodes... 

GOx (22a). (b) protonated nitromerocyanine-tethered GOx, (22b). I nset Reversible photo-switchable amperometric transduction of the bioelectrocatalyzed oxidation of glucose by 22a - ( ) and 22b-(o). 

Table 2 summarizes different possible applications of photoswitchable biomaterials, while detailing the nature of the biomaterial, the area of application, and, when possible, specific examples. Reversible light-induced activation and deactivation of redox proteins (enzymes) corresponds to write - read - erase functions. The photonic activation of the biomaterial corresponds to the write function, whereas the amperometric transduction of the recorded optical information represents the read function of the systems. Switching off of the redox functions of the proteins erases the stored photonic information and regenerates the photosensory biomaterial. These integrated, photoswitchable redox enzyme electrode assemblies mimic logic functions of computers, and may be considered as first step into the era of biocomputers. 

Photoswitchable redox-enzymes 1. Amperometric transduction of optical information - biocomputers 2. Amplification of weak optical signals -photonic amplifiers 3. Multisensor arrays — biosensor and bioelectronics 4. Photoelectrochemical systems Enzyme immobilized on electronic transducer... 

Figure 5.42 Cyclic amperometric responses of a ft-CD functionalized monolayer on photoswitching of the bipyridinium-azobenzene diad currents are measured at a constant potential of —0.6 V. From M. Lahav, K. T. Ranjit, E. Katz and I. Willner, Photosimulated interactions of bipyridinium-azobenzene with a /3-aminocyclodextrin monolayer-functionalized electrode An optoelectronic assembly for the amperometric transduction of recorded optical signals, Isr.. Chem., 37, 185-195 (1997). Reproduced by permission of Laser Pages...

Doron A, Portnoy M, Lion-Dagan M, Katz E, Willner I. Amperometric transduction and amplification of optical signals recorded by a phenoxynaphthacenequinone monolayer electrode photochemical and pH-gated electron transfer. / Am Chem Soc 1996 118 8937 14. 

Willner I, Lion-Dagan M, Marx-Tibbon S, Katz E. Bioelectrocatalyzed amperometric transduction of recorded optical signals using monolayer-modified Au-electrodes. J Am Chem Soc 1995 117 6581-92. 

Willner I, Blonder R, Katz E. Reconstitution of apo-glucose oxidase with a nitrospiro-pyran-modified FAD cofactor yields a photoswitchable biocatalysts for amperometric transduction of recorded optical signals. J Am Chem Soc 1996 118 5310-11. 

Electrical communication with electrodes and the amperometric transduction of biorecognition... 

Electronic and optical transduction of the formation of antigen-antibod/ affinity compleK-es on transducers (A) Amperometric transduction at an electrode (R /R is a redox label in the riec-trolyte solution). (B) Tnuisduction by faradic impedance >ectro cc. (C) hterogravimetric tpiartz crystal microbabnce (QCM) transduction in the presence of a piezoelectric quartz crystal. (D) Surface plasmon resonance transduction. 

Doron, A., Katz, E., Portnoy, M., and Willner, I. An electroactive photoisomcnzable monolayer-electrode A command surface for the amperometric transduction of recorded optical signals. Angew. Chem. Int. Ed. Engl., 1996, 35,1535-1537. 

Willner, I., Katz, E., Willneg B., Blondei R., Heleg-Shabtai, V., and Buckmann, A. F. Assembly of functionalized monolayers of redox proteins on electrode surfaces novel bioelectronic and optobioelectronic systems. Biosens. Bioelectron. 1997,12, 337-356. Blonder R., Katz, E., Willneg I., Wray, V., and Buckmann A. F. A lication of a nitro-spiropyran-FAD reconstituted glucose oxidase and cfuurged electron inediators as optobioelectronic assemblies for the amperometric transduction of recorded cortical signals control of the ON - OFF direction of the photoswitch. J. Am. Chem. Soc. 1997, 119, 11747-11757. 

Lion-Dagan, M., Katz, E., and Willnei L Amperometric transduction of optical signals recorded by organized monolayers of photoisomerizable biomaterials on Au-eleetrodes. /. Am. Cfiew. Soc. 1994,116, 7913-7914. 

Katz, E, Lion-Dagan, M., and Willner, I. Control of electrochemical processes by photo-isomerizable spiropyran monolayers immobilized onto Au-electrodes Amperometric transduction of optical signals. J. Electroanal. Chem. 1995, 382,25-31. 

Carbaryl AChE and BchE. Amperometric transduction Fruit and vegetables juices 0.5-2500mg L 1 (carbaryl) 3... 

The photoregulated electrical interactions between the various redox proteins and the electrode interfaces provide a means for the amperometric transduction and amplification of recorded optical signals. These integrated assemblies reveal the fundamental potential for future bioelectronic devices. 

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