Antecedent:

A quick and specific detection of biological warfare agent is the keystone in several fields like environmental control, clinic diagnostic, food industry, security and defence. The specificity of antigen-antibody binding is used in a multitude of biosensors like biological warfare-agent detection equipment. However, how the antibody is attached to the biosensor surface, in terms of density, orientation and stability, will determine the diagnosis capability of the device.

Aim:

the development of antibodies immobilization proceedings in planar surface for an efficient antigen-antibody reaction to be used in immunological sensing devices.

Material and Methods:

three immobilization methods of fluorescein labelled antibody were assayed on Zprobe membrane: passive adsorption, covalent bond by glutaraldehyde, well-oriented immobilization by the intermediate protein A/G. Bovine serum albumin labelled with R-phycoerytrin was selected as toxin surrogate. 0,5 % glutaraldehyde and A/G chimeric protein (5 and 10 µg) were used as immobilization reactive.

Results:

immobilized antibody retention during the immunocapture process was similar between all the assayed immobilization methods. The immobilized antibody density by glutaraldehyde was higher than that by protein A/G. However, with regard to the antigenic immune-capture efficiency antibody immobilization by glutaraldehyde was the less efficient than immobilization by protein A/G.

Conclusions:

Antibody immobilization by glutaraldehyde, in spite of increasing the retained antibody density on the Zprobe membrane, interferes in the antigenic immunodetection whereas the intermediate protein A/G improves it, allowing a very efficient immunocapture system with less antibody density.