One of the greatest challenges of nanoparticle cancer therapy is the delivery of adequate numbers of nanoparticles to the
tumor site. Iron oxide nanoparticles (IONPs) have many favorable qualities, including their nontoxic composition, the
wide range of diameters in which they can be produced, the cell-specific cytotoxic heating that results from their
absorption of energy from a nontoxic, external alternating magnetic field (AMF), and the wide variety of
functional coatings that can be applied. Although IONPs can be delivered via an intra-tumoral injection to some tumors,
the resulting tumor IONP distribution is generally inadequate; additionally, local tumor injections do not allow for the
treatment of systemic or multifocal disease. Consequently, the ultimate success of nanoparticle based cancer
therapy likely rests with successful systemic, tumor-targeted IONP delivery.
In this study, we used a surface-based, bilateral, noninvasive static magnetic field gradient produced by neodymiumboron-
iron magnets (80 T/m to 130 T/m in central plane between magnets), a rabbit ear model, and systemicallydelivered
starch-coated 100 nm magnetic (iron oxide) nanoparticles to demonstrate a spatially-defined increase in the
local tissue accumulation of IONPs. In this non-tumor model, the IONPs remained within the local vascular space. It is
anticipated that this technique can be used to enhance IONP delivery significantly to the tumor parenchyma/cells.