Avidin-Biotin Advantages

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 biological assays. Biotinylated antiatrazine antibodies can be easily immobilized on the surface of the avidin-modified transducer through the avidin-biotin reaction since antibodies can be readily linked to biotin without serious effects on their biological, chemical, or physical properties. Moreover, antiatrazine antibodies can be easily immobilized on the surface of the Protein A-modified transducer without any modification of the antibodies. 

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. 

One advantage of indirect avidin-biotin method is an amplification of the detection system. For example, after biotin conjugated 2° antibody, avidin is incubated, binding to the available biotins. After the remaining free avidin is rinsed off, a biotin conjugated to 488 fluorophore is added and it binds to the remaining sites on the avidin. With this method, amplification occurs because any avidin can be attached to multiple biotins conjugated with either fluorescent or enzyme. This method requires two additional incubation steps of the indirect immunocytochemistry with fluorescent-labeled 2°. 

Another simple detection method is the polymer-based detection system. This detection system does not depend on the avidin-biotin interaction for localization of the marker enzyme to the antigen but bases on an enzyme conjugated polymer backbone vith attached secondary (link) antibody. This method has the advantage to join both secondary antibody step and the detection complex incubation step in a single step. Consequently, it is a more rapid method and the blocking of the endogenous biotin activity is not necessary. 

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