Fluorescence Polarization Immunoassays (FPIA) refers to a type of immunoassay technique used in biochemistry and medical diagnostics to detect and quantify the presence of specific molecules or analytes in biological samples. It is based on the principle of fluorescence polarization, which measures the degree of rotation of fluorescently labeled molecules when they are exposed to polarized light.
In FPIA, the analyte of interest, often a protein or small molecule, is tagged with a fluorescent molecule. A specialized instrument is then used to emit polarized light and measure the fluorescence intensity emitted by the bound and unbound forms of the labeled analyte. When the labeled analyte is bound to its corresponding antibody or receptor, it exhibits a slower rotation, resulting in higher fluorescence polarization. Conversely, when the labeled analyte is unbound or free in solution, it rotates more freely, resulting in lower fluorescence polarization.
The fluorescence polarization signals are used to determine the concentration of the analyte in the sample. By comparing the polarization of the unknown sample with standard samples of known concentration, the amount of analyte can be quantified.
Fluorescence Polarization Immunoassays offer several advantages over other immunoassay methods, including higher specificity, wider dynamic range, faster assay times, and less interference from sample matrix effects. They find applications in various fields such as clinical diagnostics, drug discovery, environmental monitoring, and food safety testing.
