(Phys.org) —Nano-sized crystals of magnetic material can be found in a wide variety of organisms. Among the most studied are magnetotactic bacteria, which can orient and navigate using biosynthesized magnetosomes. These organelles are made from iron oxide or iron sulphide particles and may eventually have many therapeutic applications. When used in conjunction with new MRI-based methods, they can potentially be used as contrast agents or magnetic labels in imaging, or for drug delivery and local hyperthermic heating in treatment. A better understanding of how these magnetosomes are biomineralized, and how the three-dimensional fields that originate from them are structured is essential to achieve these goals. A new report this week in Nature describes an optical magnetic imaging technique that can be used to map magnetic field variations on the nanoscale. The author's wide-field microscopy technique allows parallel optical and magnetic imaging of many individual cells across a field of 100 microns or more.
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