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Advances in magnetic nanoparticle hyperthermia are opening new doors in cancer therapy. As a standalone or adjuvant
therapy this new modality has the opportunity significantly advance thermal medicine. Major advantages of using
magnetic magnetite (Fe3O4) nanoparticles are their highly localized power deposition and the fact that the alternating
magnetic fields (AMF) used to excite them can penetrate deeply into the body without harmful effect. One limitation,
however, which hinders the technology, is the problem of inductive heating of normal tissue by the AMF if the
frequency and fields strength are not appropriately matched to the tissue. Restricting AMF amplitude and frequency
limits the heat dose which can be selectively applied to cancerous tissue via the magnetic nanoparticle, thus lowering
therapeutic effect. In an effort to address this problem, particles with optimized magnetic properties must be developed.
Using particles with higher saturation magnetizations and coercivity will enhance hysteresis heating increasing particle
power density at milder AMF strengths and frequencies. In this study we used oil in water microemulsions to develop
nanoparticles with zero-valent Fe cores and magnetite shells. The superior magnetic properties of zero-valent Fe give
these particles the potential for improved SAR over pure magnetite particles. Silane and subsequently dextran have been
attached to the particle surface in order to provide a biocompatible surfactant coating. The heating capability of the
particles was tested in-vivo using a mouse tumor model. Although we determined that the final stage of synthesis,
purification of the dextran coated particles, permits significant corrosion/oxidation of the iron core to hematite, the
particles can effectively heat tumor tissue. Improving the purification procedure will allow the generation Fe/Fe3O4 with
superior SAR values.
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