Browsing by Author "Bell, Andrew"

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    A Microfluidic Device for Sorting Cells According to Suspended Nanoelectrode Electrophysiology
    (2017-08-14) Bell, Andrew; Robinson, Jacob T
    Electrically active tissues and cells are found in all kingdoms of life and allow us to perceive, process, and impact our environment. Despite the ubiquity and importance of electrical activity in biology, the genes and proteins controlling many electrically dependent abilities remain incompletely characterized. Electrically excitable cells are highly specialized, frequently resulting in a high degree of heterogeneity, and when analyzing at a population level, the proteins or genes responsible for the behavior of a few cells are quickly drowned out. To facilitate separation of subpopulations of electrically active cells, we have designed, fabricated, and tested a device incorporating nanoelectrodes into a micro uidic chip for sorting cells based on their electrophysiology.
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    The magnetocaloric model of natural magnetosensation
    (2019-04-15) Bell, Andrew; Robinson, Jacob T
    Many animals are able to sense the earth’s magnetic field, including varieties of arthropods and members of all major vertebrate groups. The existence of this magnetic sense is widely accepted, and this magnetic control of cellular activity is of great interest in the development of targetable noninvasive neuromodulatory tools as well as from a basic biology perspective. However, the mechanism of action of natural magnetosensation remains unknown, forcing researchers to turn to develop synthetic approaches to stimulate cells using magnetic fields. I discuss how the magnetocaloric effect could explain the puzzling performance of recent synthetic magnetosensors, and outlines a model for natural magnetosensation based on the rotating magnetocaloric effect. These models predicts that heat generated by magnetic nanoparticles may allow proteins to respond to changes in the applied field and allow animals to detect features of the earth's magnetic field. Using these models, I identify the conditions required for the rotating magnetocaloric effect to produce detectable physiological signals in response to the earth's magnetic field, and suggest experiments to distinguish between candidate mechanisms of magnetoreception. Finally, these models also have important implications for the rational design of synthetic magnetically sensitive biological systems. Accordingly I explore the promise and requirements of the development of improved magnetosensory protein complexes and novel bio-compass systems based on principles from the magnetocaloric model of natural magnetosensation.