Biosensor reagentless

Since ideally, a biosensor should be reagentless, that is, should be able to specifically measure the concentration of an analyte without a supply of reactants, attempts to develop such bioluminescence-based optical fibre biosensors were made for the measurements of NADH28 30. For this purpose, the coreactants, FMN and decanal, were entrapped either separately or together in a polymeric matrix placed between the optical fibre surface and the bacterial oxidoreductase-luciferase membrane. In the best configuration, the period of autonomy was 1.5 h during which about twenty reliable assays could be performed. 

B.H. Liu, F. Yan, J.L. Kong, and J.Q. Deng, A reagentless amperometric biosensor based on the coimmobilization of horseradish peroxidase and methylene green in a modified zeolite matrix. Anal. Chim. Acta 386, 31-39 (1999). 

S.Q. Liu and H.X. Ju, Reagentless glucose biosensor based on direct electron transfer of glucose oxidase immobilized on colloidal gold modified carbon paste electrode. Biosens. Bioelectron. 19, 177-183 (2003). 

The reactive NP core provides an alternate use for catalytic NPs as sensitive electrocatalytic tags for biosensors. Brozik and coworkers have developed a reagentless electrochemical immunoassay by using electrocatalytic NP modified antibodies that are sensitive to the oxygen reduction reaction.74 Gold/palladium core-shell... 

M. Niculescu, T. Erichsen, V. Sukharev, Z. Kerenyi, E. Csoregi and W. Schuhmann, Quinohemoprotein alcohol dehydrogenase-based reagentless amperometric biosensor for ethanol monitoring during wine fermentation, Anal. Chim. Acta, 463(1) (2002) 39-51. 

C.A. Galan-Vidal, J. Munoz, C. Dominguez and A. Alegret, Glucose biosensor based on a reagentless graphite-epoxy screen-printable biocomposite, Sens. Actuators B Chem., 45 (1997) 55-62. 

Building films a layer at a time allowed us to incorporate catalytic metallopolyion catalysts for DNA oxidation into reagentless toxicity biosensors. Two polyions containing Ru(bpy)2+ were used that are capable of cat-alytically oxidizing guanines in DNA. The one shown below, denoted Ru-PVP, has 6 Ru-N bonds and reversible oxidation at 1.15 V vs. SCE. 

Reagentless biosensors - biosensors Real electrode area - electrode surface area Real part of impedance impedance... 

This review is a survey of the research on the direct electron transfer (DET) between biomolecules and electrodes for the development of reagentless biosensors. Both the catalytic reaction of a protein or an enzyme and the coupling with further reaction have been used analytically. For better understanding and a better overview, this chapter begins with a description of electron transfer processes of redox proteins at electrodes. Then the behaviour of the relevant proteins and enzymes at electrodes is briefly characterized and the respective biosensors are described. In the last section sensors for superoxide, nitric oxide and peroxide are presented. These have been developed with several proteins and enzymes. The review is far from complete, for example, the large class of iron-sulfur proteins has hardly been touched. Here the interested reader may consult recent reviews and work cited therein [1,19]. 

For biosensors of the third generation DET to small redox proteins is of particular interest as they show interaction with reactive (oxygen) species, while enzymes in direct electric contact are suitable for reagentless metabohte measurement. Peroxidase, catalase and superoxide dismutase are also relevant to the determination of reactive oxygen species and their scavengers. 

Liao et al. have applied magnetic nanoparticles for development of a reagentless disposable amperometric ethanol biosensor. The electrochemical characteristics of modified electrode investigated by cyclic voltammetry, have been found as linearity (1-9.0 mM), sensitivity (0.61pAmM 1) and response (20 s) [102],... 

Fu, Y. Yuan, R. Chai, Y. Zhou, L. Zhang, Y., Coupling of a reagentless electrochemical DNA biosensor with conducting polymer film and nanocomposite as matrices for the detection of the HIV DNA sequence, Anal. Lett. 2006, 39, 467 182... 

Renard, M. Belkadi, L. Hugo, N. England, P. Altschuh, D. Bedouelle, H. J., Knowledge-based design of reagentless fluorescent biosensors from recombinant antibodies, J. Mol. Biol. 2002, 318, 429—442... 

Smutok, O. Ngounou, B. Pavlishko, H. Gayda, G. Gonchar, M. Schuhmann, W., A reagentless bienzyme amperometric biosensor based on alcohol oxidase/peroxidase and an os-complex modified electrodeposition paint, Sens. Actuator B-Chem. 2006,113, 590-598... 

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