Antigen-antibody affinity amperometric

FIG. 7.30 Electronic and optical transduction of the formation of antigen-antibody affinity complexes on transducers (A) Amperometric transduction at an electrode (R /K Is a redox label In the electrolyte solution). (B) Transduction by faradic Impedance spectrosco . (C) Microgravimetric quartz crystal microbalance (QCM) transduction in the presence of a piezoelectric quartz crystal. (D) Surface plasmon resonance transduction. 

Suleiman and Xu [128] described a novel reusable amperometric immuno-sensor for the determination of cocaine. Horseradish peroxidase and benzoylecgonine-antibody were co-immobilized on a chemically activated affinity membrane, which was then mounted over the tip of an oxygen electrode. The enzymatic electrocatalytic current response to the substrate is inhibited by the association of the antigen to the co-immobilized antibody. The calibration plot for cocaine was linear in the concentration range of lx 10 -1x10 M. 

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