Fluorescence Anisotropy Imaging Using a Low-Cost, Polarization-Sensitive CMOS Camera

Fluorescence anisotropy imaging is a commonly used technique for the study of biomolecular dynamics. It utilizes the polarization properties of fluorescence emissions that occur from structural and orientation changes of fluorophores. This can be an important tool to observe protein binding and orientation for dynamic biological studies. However, traditional fluorescence anisotropy imaging systems require the use of either multiple detectors or exposures to measure the extent of polarization in the emitted light. We present the capability of using a polarization-sensitive camera as a low-cost method for performing single-exposure fluorescence anisotropy imaging. The microscope design utilizes a polarization-sensitive CMOS sensor capable of performing simultaneous measurements of different polarization channels. When combined with a scanning light-sheet microscope, the method can achieve high-speed, 3D observations of cellular dynamics at sub-micro resolution, which enables functional light-sheet imaging of key biological activities, such as actin cytoskeleton dynamics during cell migration. Preliminary data suggests this approach is a strong candidate to incorporate with in vivo two-photon light-sheet imaging of deep tissue samples.