Sensitivity, immunosensor

Gene, R., Murphy, D., Fragoso, A., Ortiz, M., O Sullivan, C. K. Signal-enhancing thermosensitive liposomes for highly sensitive immunosensor development. Anal. Chem. 83, 563-570 (2011)... 

Figure 32 Scheme of mass-sensitive immunosensor for afla-toxin Bi (AFBi) based on AuNPs. Bovine serum albumin (BSA) was used for blocking after BSA-AFBi was immobilized to the AuNPs, followed by the indirect competition immunoassay. The amplification of the signals was accomplished by introducing a secondary antibody coated AuNP. 

Du, D., Z. Zou, Y. Shin et al. 2010. Sensitive immunosensor for cancer biomarker based on dual signal amplification strategy of graphene sheets and multienzyme functionalized carbon nanospheres. Anal. Chem. 82 2989-2995. 

The development of immunosensors is one of the most active research areas in immun-odiagnostics. A large number of immunosensors, which combine the sensitivity and specificity of immunoassays with physical signal transduction, have been developed... 

Heideman R.G., H. Kooyman R. P., Greve J., Performance of a highly sensitive optical waveguide Mach-Zehnder interferometer immunosensor, Sensors and Actuators B 1993 10 209-217. 

J. Zeravik, T. Ruzgas, and M. Franek, A highly sensitive flow-through amperometric immunosensor based on die peroxidase chip and enzyme-channeling principle. Biosens. Bioelectron. 18,1321—1327 (2003). 

There is a continuing demand for fast and simple analytical methods for the determination of many clinical, biochemical and environmental analytes. In this respect, immunoassays and immunosensors that rely on antibody-antigen interactions provide a promising means of analysis owing to their specificity and sensitivity. High specificity... 

A similar study has also been conducted to determine the suitability of ascorbic acid 2-phosphate (AAP) as an alternative substrate to 4-AP for AP under identical conditions [48], Although 4-APP and AAP were suitable substrates for amperometric immunosensors, 4-APP was superior owing to its sixfold faster enzymatic reaction and lower detection potential (approximately 200-400mV). Notably, the lower detection potential for the hydrolysis product of 4-APP minimizes interferences from other species and hence improves the sensitivity of the immunosensor. 

There are mainly three types of transducers used in immunosensors electrochemical, optical, and microgravimetric transducers. The immunosensors may operate either as direct immunosensors or as indirect ones. For direct immunosensors, the transducers directly detect the physical or chemical effects resulting from the immunocomplex formation at the interfaces, with no additional labels used. The direct immunosensors detect the analytes in real time. For indirect immunosensors, one or multiple labeled bio-reagents are commonly used during the detection processes, and the transducers should detect the signals from the labels. These indirect detections used to need several washing and separation steps and are sometimes called immunoassays. Compared with the direct immunosensors, the indirect immunosensors may have higher sensitivity and better ability to defend interference from non-specific adsorption. 

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