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Jong-Ki Kim1 Younshick Choi1 Jae-Kun Jeon1

1, Catholic University of Daegu, Daegu City, , Korea (the Republic of)

Magnetite (Fe3O4 nanoparticles) was known to be present in Amyloid plaques in Alzheimer patient. In vitro this nanoparticle induces Aβ-fibril formation under saturated concentration. Redox activity of iron depends on its ionic status, and plays an important role in toxicity of Aβ-fibril/amyloid plaque. We have attempted to image the magnetite distribution in a macrophage cell and nanoradiator-based ROS formation using zone-plate based synchrotron X-ray STXM-XAS method, which allows focusing of Fe L-edge X-ray beam as 30 nm, irradiating almost single nanoparticles in a single cell, and producing low-energy electron and measurement of redox activity of iron: Fe(II) (redox active), Fe(III)(redox inactive). In the presence Aβ42 peptide, FeCl3 induced Aβ fibril, rendering redox active Fe(II), while traversing proton irradiation converted into redox inactive Fe(III) with disrupted Aβ-fibril which was confirmed TEM imaging. In this connection, we investigated magnetite-mediated induction of Aβ-fibril formation and its redox status of Fe(II), and after proton irradiation, major redox status of magnetite was monitored which in turn turned into Fe(III) compared to initial overriding Fe (II) in Aβ-fibril before proton irradiation. These results suggest traversing proton beam may be used for novel redox change therapy in the amyloid plaque in Alzheimer disease patient.

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