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limited to magnetic dichroism but can be applied to other chiral signals such as optical dichroism, valley polarization, skirmions, complex topological vortex electrical polarization, and other novel states of matter. T e new technique also could provide a mechanistic understanding of the behavior of magnetic nanoparticles under investigation for gene and drug delivery.

Livecyte ® Kinetic Cytometer Phasefocus

Developers: Martin Humphry, Kathryn Cooper, Tim Godden, Richard Kasprowicz, Bhupalreddy Kumbhum, Kevin Langley, Andrew O’Brien, James Russell, Chris Shuttle, Matthew Stagg, Rakesh Suman, and Joanne Whetstone

The Livecyte Kinetic Cytometer uses ptychographic quantitative phase imaging (QPI) microscopy to measure and analyze the behavior of single or multiple live cell types, on a cell-by-cell basis and on a population basis, in long time-lapse sequences

typically lasting many hours or days. Culture samples are prepared by the user in industry-standard micro-well plates and studied within an integral incubator that maintains optimal temperature, humidity, and carbon dioxide levels. A custom-designed “Sample Pod” protects cells during transport from the user’s laboratory into the system and permits perfect realignment if the cells need to be removed temporarily during an experiment (for example to add a drug treatment or replace culture media). In QPI, images with very high inherent contrast are generated as a result of phase delays introduced as the illuminating light passes through the cells, eliminating the necessity for exogenous stains or labels.

Intuitive graphical user interface tools may be used to program fully automated ptychographical time-lapse workflows interspersed (when desired) with conventional fluorescence imaging. The combination of ptychography and fluorescence imaging enables special measurement protocols such as the extraction of single-cell or cell-population kinetic phenotypes in parallel with fluorescence-based functional studies. Imaging may be performed continuously and automatically over multiple regions of interest within single or multiple wells. Livecyte’s Cell Analysis Toolbox software provides automated cell tracking that can track hundreds of cells on an individual basis. Typical automated assays and analyses include the following: cell motility, speed, and meandering index; cytotoxic response and cell viability including apoptosis rate; dynamic proliferation analysis including time-resolved mitotic index measurement; and morphological cell parameter measurements (dry mass, volume, sphericity, etc.). Traditional fl uorescence microscopes oſt en employ high light intensities that can induce photobleaching and phototoxicity.


By comparison, ptychography’s inherently high contrast, and Livecyte’s illumination power thousands of times lower than fl uorescence methods, off er an extremely “gentle” experimental environment.

Applications well suited for Livecyte include analysis of the phenotypic behavior of “closer to real life” patient- derived primary cells and stem cells as they come under the influence of pharmaceutical drug candidates, including drugs that are uniquely toxic to cancer cells or, conversely, drugs that encourage cell behaviors associated with wound healing.

Benthic Underwater Microscope

Scripps Institution of Oceanography, University of California at San Diego

Developers: Andrew D. Mullen, Tali Treibitz, Paul L.D. Roberts, and Jules S. Jaff e

Biological processes occurring at microscopic scales significantly impact the health of important marine ecosystems, including coral reefs and kelp forests. It is critical to observe such processes in their natural settings because of the complex biological physical interactions occurring in the ocean environment. The benthic

underwater microscope is the first instrument capable of acquiring microscopic images of seafloor organisms in situ, in the natural underwater environment. This diver-operated system allows non-invasive observations of live, three- dimensional specimens at a resolution of ~2 µm. Unique challenges of underwater microscopy are overcome through the combination of three principal optical components: a long-working-distance microscope objective, an electrically tunable lens (ETL), and focused reflectance illumination. A long-working-distance objective lens provides the numerical aperture needed to resolve fine details, while also offering sufficient working distance to leave the subject undisturbed. Rapid focusing is achieved through the use of a shape-changing ETL; the curvature of this deformable lens can be controlled in order to modulate the system’s focal length. This produces a compact means of bringing a subject into precise focus as well as providing the ability to scan through a volume, in order to collect focal stacks of three-dimensional subjects. Finally, a ring of focused LEDs provides high-intensity reflectance illumination, which allows the short exposures needed to prevent motion blur. The optical system is integrated into a submersible package that includes camera, electronics, and user interface. The system has been used to collect still images as well as videos and overnight time-series image sets showing organism behaviors. By allowing observations at important yet previously unattainable scales, the instrument provides a new window into the marine world. • 2017 September

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