Polarized light imaging of birefringence and diattenuation at high resolution and high sensitivity

Abstract

Polarized light microscopy provides unique opportunities for analyzing the molecular order in man-made and natural materials, including biological structures inside living cells, tissues, and whole organisms. 20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging and digital image processing for fast and comprehensive image acquisition and analysis. The LCPolScope is commonly used for birefringence imaging, analyzing the spatial and temporal variations of the differential phase delay in ordered and transparent materials. Here we describe an alternative use of the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship between the quantities measured with either instrument, and touch on the physical connection between refractive index, birefringence, transmittance, diattenuation, and dichroism.

Detecting ordered small molecule drug aggregates in live macrophages: a multi-parameter microscope image data acquisition and analysis strategy

“…The development and refinement of polarized light microscopy measurements to study changes in the organization of molecular components in individual cells has had many applications in cell biology and beyond [4,31,32]. To study the bioaccumulation of small molecule drugs inside cells, the experiments presented here indicate how a quantitative multiparameter imaging system combining polarization, transmittance and fluorescence measurements can be useful for studying the cellular mechanisms of drug disposition from the cellular to the molecular level.…”

“…Polarization measurements are acquired utilizing the diattenuation LC-PolScope microscope, a custom built microscopic imaging system similar to the birefringence LC-PolScope designed by Oldenbourg et al [4], but without the polarization analyzer. Our LC-PolScope is built on the Nikon Eclipse Ti inverted microscope (Nikon Instruments, Melville, New York), with the computer-controlled universal compensator (Hinds Instrumentation, Hillsboro, Oregon) placed between the interference filter (623 ± 23 nm, Semrock Optics, Rochester, New York) and condenser lens (Fig.…”

“…Similar to conventional, transmitted light microscopy, polarization microscopy instruments can employ polarized, transmitted light to study the structure of supramolecular aggregates within individual cells [4][5][6][7]. Because of the manner in which polarized light interacts with ordered molecular structures, differences in the organization of molecular components can be detected and quantified based on the fraction of light that is transmitted through the material when it is illuminated with polarized light [8].…”

pH dependent isotropic to nematic phase transitions in graphene oxide dispersions reveal droplet liquid crystalline phases

“…The main advantage of LC-Polscope compared to traditional polarizing microscopes is that it can measure the retardance or diattenuation along with their dominant orientation simultaneously at all points of the image without having to mechanically rotate the specimen. Note that the birefringence measurement is affected by the diattenuation, but the diattenuation is sensitive only to differential transmittance, as detailed in Mehta et al 23 and demonstrated for reduced-GO in Tkacz et al 24 In the two extreme cases of pH 1 and 14, the suspensions did not form liquid crystals at any concentration due to aggregation of GO platelets (see S2 in ESI for further details). At pH 2, 6, and 9, a complete phase separation was observed after 4-6 days, with I phase at the top and N phase at the bottom of the capillary.…”

Integrated Mueller-matrix near-infrared imaging and point-wise spectroscopy improves colonic cancer detection

“…Polarized light imaging/spectroscopy has been comprehensively investigated for tissue diagnosis [6][7][8][9][10][11][12][13][14][15][16][17]. Polarized light implementation offers several compelling advantages as follows: (i) surface and beneath-the-surface detection of biological tissue taken from the tissue depolarization properties [11,15]; (ii) tissue anisotropy analysis through the tissue diattentuation and retardance [13,14]; (3) enhanced tissue diagnosis through the combination of complementary depolarization, diattentuation and retardance of the tissues [9].…”