Enzyme immunosensor, thin-layer

As mentioned above, GC and LC techniques (and GC-MS and LC-MS in particular) represent the major determinative approaches used in current MMRMs. Other, much less widely applicable and applied techniques include (1) capillary electrophoresis and capillary electrochromatography (2) thin-layer chromatography and (3) an array of immunoassays, such as immunosensors and enzyme-linked immunosorbent assay (ELISA). Immunoassays are, however, relatively useful for sensitive and rather rapid and inexpensive screening (followed by a confirmatory method in the case of a positive response) of selected pesticides for which ELISA kits or sensors are available. 

Potentiometric electrodes have been used as transducers in biosensors in which a thin layer containing enzymes, antibodies, or whole cells separates the electrode surface from the analyte solution and provides selective recognition properties. Thin layers containing enzymes or cells catalyze reactions that cause the localized production or consumption of the species to which the electrode responds. Antibodies, incorporated into immunosensors, have been shown to cause small but measurable signals upon antigen binding, but usually require a label (such as an enzyme) that allows catalysis of a reaction that can be followed potentiometrically [13]. 

YIN ET AL. Thin-Layer Flow-Through Enzyme Immunosensor... 

Biosensors based on biorecognition events occurring in monolayer or thin-fihn assemblies on electronic transducers represent an important recent advance in bioelectronics [15]. The nano-architecture of the sensing interface in a mono-layer, multilayer, or thin-fihn structures precludes diffusion barriers, and hence the rapid response-times of the sensing devices are achieved. Enzyme-electrodes [16,17], immunosensors [18,19], or DNA sensors [13] were developed by tailoring nanoscale sensing interfaces on the transducer. We will specifically address the development of DNA sensors in monolayer and thin-film confignrations. 

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