Project Summary This study focusses on the synthesis and characterization of an entirely new class of iron nanoparticles that transition to iron oxide nanoparticles (in vivo) over a controllable period consistent with providing biocompatibility and novel function. After synthesis, the particles will be characterized to reveal their size, structure, size distribution and magnetic properties. The degree of oxidation of FeNPs will be assessed by Mössbauer spectroscopy. The in vitro biocompatibility will be determined at various extents of oxidation. The magnitude of magnetic particle imaging signal and resolution will be determined as a function of FeNP oxidation. The Specific Aims of our research include: 1) The synthesis of iron nanoparticles for biomedical applications; 2) physical characterization and magnetic property determination of the iron nanoparticles; and 3) quantitative characterization of FeNPs, biocompatibility and MP image contrast capability in mammalian cells. We will create iron nanoparticles of uniform size with coatings that allow controllable oxidation. We will then demonstrate the transformative capabilities of these materials in producing a more sensitive nanoparticle for magnetic particle imaging. The new nanoparticle performance will be compared with VivoTrax, a commercial FeOxNP. Dr. Jacqueline Johnson’s group has performed preliminary research in the development of these nanoparticles and Dr. Johnson is a leading expert on the analysis of magnetic materials using Mössbauer spectroscopy as well as many preliminary characterization methods. Dr. Giorgio’s group has extensive experience in appropriate coatings of nanoparticles and transmission electron microscopy studies. Dr. Lu is an expert in nanoparticle chemistry; Dr. Lu and graduate research assistant, Aleia Williams, have been developing synthesis methods of FeNPs since 2020. This project will form the basis of Aleia’s and Vanderbilt GRA’s PhD work, summer research for interns at UTSI and research projects for resident undergraduates at Vanderbilt, for the duration of the project. In total, this is training for 8-10 students at various levels. The group will assess imaging performance as investigated by the company Magnetic Insight, who are developing instrumentation for Magnetic Particle Imaging.

PROJECT NARRATIVE This study is focused on the synthesis and characterization of an entirely new class of elemental iron (not iron oxide) nanoparticles. The work is transformative, as it will create iron nanoparticles that oxidize in a controlled way to enable both high performance (initially) and good biocompatibility, equivalent to iron oxide nanoparticles, over a suitable timeframe. We will then demonstrate how these nanoparticles can perform as enhanced magnetic particle imaging contrast agents.