2018/08/31 by Ilja Fescenko, Abdelghani Laraoui, Janis Smits +6 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #physics.bio-ph
paper · pdf · doi:10.1103/physrevapplied.11.034029
published as Phys. Rev. Applied 11, 034029 (2019) · Main text: 8 pages and 5 figures, Supplemental Information: 9 pages and 8 figures
arxiv created 2018/09/19 · arxiv updated 2019/03/27
Magnetic microscopy of malarial hemozoin nanocrystals was performed using optically detected magnetic resonance imaging of near-surface diamond nitrogen-vacancy centers. Hemozoin crystals were extracted from Plasmodium-falciparum-infected human blood cells and studied alongside synthetic hemozoin crystals. The stray magnetic fields produced by individual crystals were imaged at room temperature as a function of applied field up to 350 mT. More than 100 nanocrystals were analyzed, revealing the distribution of their magnetic properties. Most crystals (96%) exhibit a linear dependence of stray field magnitude on applied field, confirming hemozoin's paramagnetic nature. A volume magnetic susceptibility χ=3.4×10-4 is inferred using a magnetostatic model informed by correlated scanning electron microscopy measurements of crystal dimensions. A small fraction of nanoparticles (4/82 for Plasmodium-produced and 1/41 for synthetic) exhibit a saturation behavior consistent with superparamagnetism. Translation of this platform to the study of living malaria-infected cells may shed new light on hemozoin formation dynamics and their interaction with antimalarial drugs.