Avidin-biotin recognition

Amounas M, Innocent C, Cosnier S et al (2000) A membrane based reactor with an enzyme immobilized by an avidin-biotin molecular recognition in a polymer matrix. J Membr Sci 176 169-176... 

In essence, the introduction of the avidin-biotin complex into a given system does not contribute a factor of specificity to an immunochemical reaction rather, its involvement serves to mediate between the recognition system (i.e., cintibody-cintigen complex) ind a given probe or reporter group. Such mediation usually results in an amplified or improved signal. 

The avidin-biotin procedure has been extensively used in hybridization studies. Since the concentration of all analysed DNAs used is identical, the total concentration of the analysed samples is high. The amplification of the base-mismatch recognition event is necessary to improve sensitivity. The use of oligonucleotide-functionahzed Uposomes or biotin-labelled liposomes as probes for the dendritic amphfication of DNA-sensing processes was characterized by Willner and co-workers [62] and showed better performance using QCM than impedance spectroscopy measurements. 

A high capacity of molecular recognition is at the basis of the structure and operation of all living systems. Many of these substances can be exploited for assays in connection with, or similar to, EIA. Currently, a few (avidin/biotin, protein A, lectins) are used to great advantage, and will contribute considerably to increase the applicability of EIA. 

Since heterocoagulation is a stochastic process, great care needs to be taken not to end up with large fractal clusters or flocks of the two colloidal components. Driving forces to promote adhesion of inorganic nanoparticles onto the surface of polymer latex particles, or vice versa, can be based on a variety of forces, such as electrostatic attraction, hydrophobic interactions, and secondary molecular interactions such as (multiple) hydrogen bond interactions and specific molecular recognition (e.g. complementary proteins like avidin-biotin). 

When two molecules need to be non-covalently brought together in the creation of a device, one can exploit the natural interaction between biotin and avidin. Biotin is a cofactor that binds to the protein receptor avidin (or strep-avidin), and the binding constant has been measured to be near 10 - M h This is one of the largest affinities associated with any molecular recognition event, and can be considered irreversible. Avidin is a tetrameric protein that binds four biotins independently. The fact that the protein binds four biotins and has such a large affinity for each, makes this system a powerful tool for assembly processes. 

The specific interaction based on molecular recognition of avidin—biotin provides a facile approach for the immobilization ofbiomolecules on solid-state smface. The avidin (streptoavidin)-based system is ideally suited for the well-controlled immobilization of biomolecules due to the specific and strong interaction between avidin and biotin. Since avidin has a nearly cubic shape with four biotin binding sites grouped in two pairs at opposite ends of the avidin molecule, it has been used for anchoring biotinylated biomolecules such as proteins and DNA thereby acting as a biocompatible linker between biotin and biotinylated biomolecules. 

First entry on each line is the tag. Square brackets enclose the probe donor + transfer enzyme (where applicable) or reaction. Probe organic fluorophores, nanoparticles (can be QDs as in methods 2, 3, 8, 9) or a bridging/recognition moiety. If desired, the latter can serve in a second orthogonal reaction ( piggyback strategy). See text. Biotin readout probes linked to avidin, streptavidin, anti-biotin 7[101] ... 

Smith CL, Milea JS, Nguyen GH (2005) Immobilization of Nucleic Acids Using Biotin-Strept(avidin) Systems. 261 63-90 Smith DK, see Hirst AR (2005) 256 237-273 Stadler A, see Kremsner JM (2006) 266 233-278 Stibor I, Zlatuskova P (2005) Chiral Recognition of Anions. 255 31-63 Stoddart JF, see Moonen NNP (2005) 262 99-132... 

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