The LC-PolScope is an advanced imaging technique for analyzing specimens that are commonly studied with the traditional polarizing microscope. It combines hardware components with software algorithms for generating high resolution maps of optical anisotropies, such as birefringence, dichroism, and polarized fluorescence. The patented technology was originally developed at the MBL in the laboratory of Rudolf Oldenbourg and is licensed to Cambridge Research and Instrumentation, Inc., now part of PerkinElmer.
At the MBL, polarized light microscopy in biology has been advanced and practiced by the work of Shinya Inoué since 1949. The current laboratories of Rudolf Oldenbourg, Michael Shribak, and Tomomi Tani continue the tradition by developing new approaches in hardware and software to harness the analytical power of polarized light imaging.
LC-PolScope schematic: The optical design (left) builds on the traditional polarized light microscope with the conventional compensator replaced by two variable retarders LC-A and LC-B. Images of the specimen (top row, aster isolated from surf clam egg) are captured at 5 predetermined retarder settings. The respective retardance values of LC-A and LC-B are shown above the images as a fraction of wavelength. Based on the raw PolScope images, the desk top computer instantaneously generates the retardance image and slow axis orientation image shown on the lower right. Acquiring raw images takes one to several seconds, depending on required sensitivity, which can be better than 0.05 nm retardance.
LC-PolScope software implements image acquisition and processing algorithms for rapidly generating pixel maps of optical anisotropies in the specimen. One map depicts the magnitude of anisotropy, irrespective of the orientation of the specimen in the plane of view. A second map depicts the orientation of the anisotropy, such as the slow axis of birefringent objects.
The LC-PolScope image to the right shows an Actinosphaerium, a single cell organism that extends radially arranged axopodia for capturing prey. The axopodia are birefringent by virtue of microtubule arrays that run along their cores and extend into the interior of the spherical cell body (diameter ~ 100 µm). In this color coded LC-PolScope image, brightness represents amount of retardance and hue represents slow axis orientation.
LC-PolScope software is being implemented as plugins for Micro-Manager, an open source platform for image acquisition and processing.
LC-PolScope plugin for Micro-Manager