Biosensors Biotin-avidin

Fig. 18.2. Biosensor scheme describing the various steps involved in the immunoassay using ITO-poly(pyrrole-biotin)-coated optical fibers for the detection of anti-cholera toxin B subunit using the biotin-avidin immobilization technique.

WB Nowall, N Dontha, WG Kuhr. Electron transfer kinetics at a biotin/avidin patterned glassy carbon electrode. Biosensors Bioelectronics 13 1237-1244, 1998. 

The binding affinity between streptavidin and biotin is among the strongest noncovalent bonds known to exist (A o = 10" M) Therefore, the high affinity coupling of the biotin-avidin system has been used to immobilize different biomolecules on the surface of biomaterials and biosensors. " - It consists of using avidin as a bridge between the biotinylated surface and biotinylated... 

Fig. 21. (Top) Schematic and chemical structure of the biosensor molecule used by Spence et al. (Bottom) Detection of biotin-avidin binding with xenon NMR. The HP Xe NMR spectra of the functionalized xenon biosensor alone and in the presence of protein. These spectra show a new resonance and marked broadening in response to the increasing amounts of avidin. (Courtesy of Connie Chung and the Pines group, adapted from ref. 314 with permission. Copyright 2004, American Chemical Society.)...

Biopolaronic structure, 8-30, 8-37 Biosensing, 6-30 Biosensors, 14-17, 14-30 Biotine--avidine, 18-28 Biotiynylated PPE, 6-41 Bipolar current, 19-4... 

A PAMAM dendrimer (G4) monolayer partially functionalized with both ferrocenyl and biotinamidocaproate residues was constructed on a Au electrode and utilized as a biosensor for avidin on the basis of its binding to biotin [110]. The electrochemical response was generated by the oxidation of free glucose catalyzed by GOx present in the electrolyte. The magnitude... 

After biotin patterns are formed on the electrode surface, biotin/avidin chemistry can be used for selective attachment of avidin-labeled biomolecules. Thus, the technique based on simple micromodification of the surface of a carbon electrode will allow the fabrication of biosensors that can potentially be tailor-made for a variety of applications. 

Narang U., Anderson G.P., King K.D., Liss H.S., Ligler F.S., Enhanced biosensor performance using an avidin-biotin bridge for antibody immobilization, Proc. SPIE. 2980 187-194,1997. 

Anzai, J. I. and Osa, T., Avidin-Biotin Supramolecular Complexation for Biosensor Application, JAI Press Inc., Greenwich, Connecticut, 1997, p. 143. 

AVIDIN-BIOTIN SUPRAMOLECULAR COMPLEXATION FOR BIOSENSOR APPLICATIONS... 

In 1989, to the best of our knowledge, the first report appeared on the use of an avidin-biotin system for the immobilization of enzymes in the preparation of biosensors. Walt et al. have immobilized biotin-modified enzymes (urease, esterase, and penicillinase) on the surface of biotin-modified optical fiber using avidin as a binder (Figure 5a). They have demonstrated the general use of this procedure in immobilizing several types of enzymes. At nearly the same time, Gunaratna and Wilson used an enzyme column in which choline esterase and choline oxidase were immobilized through avidin-biotin complexation for the determination of acetyl-... 

AVIDIN-BIOTIN SUPRAMOLECULAR COMPLEXATION EOR BIOSENSOR APPLICATIONS Jun-ichi Anzai and Tetsuo Osa... 

Confocal laser scanning fluorescence microscopy was used to study the exposure of the avidin-specific binding sites in the Av-GEB platform by the immobilization of a small and flexible biotinylated fluorescein molecule as a fluorescence marker. Fluorescence microscopy thus confirms that Av-GEB platform exposes active binding sites for biotin, acting as affinity matrix (Fig. 21.2B). After use, the electrode surface can be renewed by a simple polishing procedure for further uses, highlighting a clear advantage of this new material with respect to surface-modified approaches such as classical biosensors and other common... 

In this part we will describe recent achievements in the development of biosensors based on DNA/RNA aptamers. These biosensors are usually prepared by immobilization of aptamer onto a solid support by various methods using chemisorption (aptamer is modified by thiol group) or by avidin-biotin technology (aptamer is modified by biotin) or by covalent attachment of amino group-labeled aptamer to a surface of self-assembly monolayer of 11-mercaptoundecanoic acid (11-MUA). Apart from the method of aptamer immobilization, the biosensors differ in the signal generation. To date, most extensively studied were the biosensors based on optical methods (fluorescence, SPR) and acoustic sensors based mostly on thickness shear mode (TSM) method. However, recently several investigators reported electrochemical sensors based on enzyme-labeled aptamers, electrochemical indicators and impedance spectroscopy methods of detection. 

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