Fluorescence polarization is similar to fluorescence intensity, in that it is based on the emission of light by an excited fluorophore. However, samples are excited by polarized light which is selected by specific polarizing filters. Depending on the mobility of the fluorescent molecules in the wells, the emission light will either be polarized or not. Large molecules, such as proteins in solution, which rotate slowly due to their size, emit polarized light when excited by a polarized light. Smaller molecules, which rotate faster, emit depolarized light. Low levels of polarization indicate that the fluorescent molecules move freely in the solution, whereas high levels of polarization mean that a larger molecule complex is present. Fluorescence polarization assays which are based on this principle include binding assays or the Predictor hERG assay. Fluorescence polarization measurements on BMG LABTECH microplate readers.
Fluorescence polarization detection with BMG LABTECH microplate readers
Fluorescence polarization-based detection can be performed on the PHERAstar® FSX, CLARIOstar®, and SPECTROstar® Omega. A high-intensity xenon flashlamp provides high performance measurements, while assay-specific filters or optic modules select the specific wavelengths, and minimize unwanted background noise. Specific polarization membranes are positioned on both excitation and emission light paths.
Examples of fluorescence polarization measurements on BMG LABTECH instruments
- AN 180: High-throughput protein-DNA affinity measurements using fluorescence anisotropy
- AN 205: Membrane Fluidity Measurements Using UV Fluorescence Polarization and the POLARstar Omega
- AN 244: The CLARIOstar® surpasses the certification needed for the Transcreener® ADP² FP assay
See a complete list of fluorescence polarization application notes.
The following BMG LABTECH microplate readers can be configured to perform fluorescence polarization measurements.