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Frail Mitochondrial DNA Equals Frail People

MetadataDetails
Publication Date2015-01-01
JournalPhysical Review Applied
AuthorsRay Schilling

Magnetic microscopy of malarial hemozoin nanocrystals is performed by optically detected magnetic resonance imaging of near-surface diamond nitrogen-vacancy centers. Hemozoin crystals are extracted from <i>Plasmodium falciparum</i>-infected human blood cells and studied alongside synthetic hemozoin crystals. The stray magnetic fields produced by individual crystals are imaged at room temperature as a function of the applied field up to 350 mT. More than 100 nanocrystals are analyzed, revealing the distribution of their magnetic properties. Most crystals (96%) exhibit a linear dependence of the stray-field magnitude on the applied field, confirming hemozoin’s paramagnetic nature. A volume magnetic susceptibility of 3.4 Ɨ 10<sup>-4</sup> is inferred with use of a magnetostatic model informed by correlated scanning-electron-microscopy measurements of crystal dimensions. A small fraction of nanoparticles (4/82 for <i>Plasmodium falciparum</i>-produced nanoparticles and 1/41 for synthetic nanoparticles) exhibit a saturation behavior consistent with superparamagnetism. Translation of this platform to the study of living <i>Plasmodium</i>-infected cells may shed new light on hemozoin formation dynamics and their interaction with antimalarial drugs.