Immunological Technology

Immunoassay-Based Technologies

Immunoassay based detection with antibodies is perhaps the only technology that has been successfully employed for detection of bacterial cells, spores, viruses and toxins alike. Antibodies specific to virtually any compound can be produced so long as the compound of interest is able to trigger an immunological response. Most immunological techniques target surface antigens, which obviates the need for cell lysis or antigen purification prior to performing the assay. Both monoclonal and polyclonal antibodies have been used to develop immunoassays with the former selected for assays that are more specific, but at the expense of sensitivity and binding affinity.

Significant progress has been made in the past five years in the development of devices that employ immunological technology for the detection of Biological Assays. Consequently, immunoassays are now the most widely used analytical technique for bioassays. Recent improvements in antibody production, and the fact that immunoassays are inherently specific, selective, require minimal sample processing, and are readily adaptable to fieldable devices, have led to the quantitation and identification of a wide range of analytes including BAs.

Immunological techniques reported for the detection of BA employ both monoclonal and polyclonal antibodies that target surface antigens. Unlike nucleic-based detection technologies, this eliminates the need for cell lysis or antigen purification prior to performing the assay, which is advantageous for the detection of intact bacterial spores such as B.anthracis whose spores are not easily disrupted. Therefore, detection technologies that adopt immunological techniques are inherently rapid since minimal sample preparation is required. Several sensitive laboratory based immunoassays have been developed for BA detection with fluorescent covalent microsphere immunoassays (FCMIA) and bead-based assays with electrochemical detection, time resolved fluorescence (TRF), integrated metal clad leaky waveguide sensor, and ion channel switch array biosensor (ICS), among others.

The advances in immunological techniques have been matched by improvements in complimentary technology such as automated analyzers, microarrays for multianalyte detection, reporter systems, and microchip-based technologies. New developments and improvements in handheld and portable immunoassay systems have been reported with remarkable sensitivity and specificity. Most of these technologies employ lateral flow immunoassay formats since these are rapid, simple, and require minimal time to perform, usually between 15 min to 60 min.