Spectral Observables for Fluorescence Sensing

Figuie 19.2. Sccood-gMietation fluocesoence sensor for point-of eue testing. TnC, Troponin C Mb, myoglobin. 

Anotiier ratiometric mediod is based on die measurement of fluorescence polarization or anisotropy. In this case the analyte causes a change in the polarization of the label. Anisotropy measurements are frequently used in competitive immunoassays, in which the actual analyte displaces labeled analyte that is bound to specific antibody. This results in a decrease in the anisotropy. Anisotropy values are calculated using the ratio of polarized intensity measurements. The use of an intensity ratio makes the anisotropy measurements independent of fluorophm c(mi-centration as long as the measuremeDts are not distorted by autofluoresccnce or pow signal-to-noise ratio. Polarization immunoassays are discussed in Section 19.9X). 

SpMAN abxnNile. lor flllonnxiKC. phne-modnluioii VMine. 

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