PolarEyes with enhanced digital imaging, a high-throughput solution for locating and grading crystals

The long-range internal order of crystals enables them to exhibit a well known and long-exploited phenomenon: birefringence. Simple assessment of the interaction of crystals with a polarized light source has guided the hand of many crystallographers through history in matters of crystal selection. Historically the interaction of plane-polarized light has been analysed manually by the user. However, adapting the use of a motorized polarized light microscope to a modern small-molecule-optimized high-throughput workflow can allow for more efficient screening of crystals, in turn alleviating the analysis bottleneck previously encountered in parallel crystallization techniques, such as encapsulated nanodroplet crystallization. Presented herein are developments to an existing open-source imaging robot, including the novel integration of a commercial imaging device and a new software suite for analysis. The open-source program PolarEyes is presented for the extraction of polarization quantities from optical light micrographs. Included in PolarEyes are facilities to perform normalization against a background image and false-colour visualization using the hue, saturation, luminance colour model, and capabilities to perform analysis of multiple different incident polarization states.