Immunosensors characteristics

Immunotechniques have recently been developed to detect food contaminants, e.g., toxins, growth hormone, antibiotics, pesticides, and herbicides. Penicillin (62) in milk, aflatoxins and mycotoxins (63, 64, 65) in milk, cheeses, yogurt, corn have been detected by immunosensors. Characteristics of protein and receptors in or on the cell surface were used in detecting pathogens such as Listeria and Salmonella by immunosensors (11, 66). The principle of immunosensors has also been applied in pesticide determinations (67, 68). 

Main performance characteristics of immunosensors in clinical analysis... 

Because of their chemical stability and past industrial applications, PCBs are ubiquitous contaminants in the environment marine sediment, soil and food are the matrices where the presence of PCBs is more documented. For their characteristics electrochemical immunosensors are valid analytical tools to carry out a fast screening analysis on a large number of potentially polluted samples. 

Actually, special attention is paid in the application of biosensors in environmental analysis. The high cost and slow turnaround times typically associated with the measurement of regulated pollutants clearly indicates a need for environmental screening and monitoring methods that are fast, portable and cost-effective. To meet this need, a variety of field analytical methods have been introduced. Because of their unique characteristics, however, technologies such as DNA sensors and immunosensors based on AuNPs might be exploited to fill specific niche applications in the environmental monitoring area. 

Abstract This chapter reviews the basic theory and applications of piezoelectric immunosensors. The immunosensor assay formats most often used are introduced as well as a brief explanation of the typical methods of measurement. Immobilisation is discussed, the importance of each characteristic, the basic techniques employed and a comparison of their performance as investigated by many researchers. The main historical developments of piezoelectric sensors and how these have led to early piezoelectric immunosensors are reviewed. Immunosensor applications and a comparison of sensor performance, for various analytes are summarised. The potential future of this field is also discussed. 

Antibody-based probes (immunosensors) offer another highly specific probe technology, since antibodies recognize very specific sites or cellular components (epitopes). Antibodies specific for any microbe can be made if the microbe can be obtained in pure culture. These must be screened for binding characteristics, that is, binding affinity, on- and off-rates, and epitope recognized. The production of monoclonal antibodies requires significantly more time and effort in the development of hybridoma cell lines with appropriate characteristics. It is, therefore, desirable to provide... 

Gold nanoparticles (Au-NPs) and silver nanoparticles (Ag-NPs) are of particular interest in DNA sensors and immunosensors due to their advantageous properties, such as hydrophilicity, standard fabrication methods, excellent biocompatibility, unique characteristics in the conjugation with biological recognition elements, and multiplex capacity for signal transducer. Therefore, a large number of published methods use Au- or Ag-NPs in DNA [16,17,18] protein [19] and even cell [20] electrochemical detection besides optical detections like ICP-MS [21] or their use as ELISA enhancer [22]. 

Figure 9.20 Characteristics of an ideal immunosensor In which refers to the device, the performance, and the analytical features...

Food immunosensing is undoubtedly a growing field that will continue incorporating interesting approaches. With all the effort is being made, the future will undoubtedly bring multianalyte miniaturized immunosensor platforms that perform all testing in a fast one device-one place way with improved characteristics. 

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