Structure of magnetosomes suspensions in the presence and absence of magnetic fields.

Using iron oxide nanoparticles (IONPs) for cancer treatment has been proposed for the last twenty years. The goal is to target tumors accurately to avoid damage to healthy cells of patients. Once targeting is achieved, the application of an alternating magnetic field heats nanoparticles locally, a phenomenon referred to as magnetic hyperthermia, which can directly kill tumoral cells. Among the large body of developed IONPs, magnetosomes that are synthesized by magnetotactic bacteria (MTB) present definite advantages: such particles indeed display a homogeneous size distribution and uniform morphology are composed of high crystallinity magnetite and/or maghemite, and their magnetic moment is stable at room temperature. The aim of the proposed experiment is to use the capabilities of the MISTRAL beamline to image the structures formed in various suspensions of CA-coated magnetosomes with increasing volume fractions subjected or not to magnetic fields of increasing intensities. We should be able to quantify with excellent statistics the various chaining features of the magnetosomes, which can structure as flexible chains, rings, branched structures or a combination of them depending on the magnetosome concentration and the evolution of these structures upon application of a magnetic field. This should provide new insights on the relationships between structure and heating power features.