Interaction of Nanoparticles with RF, AC, and Static Magnetic Fields in Thermal and Non-Thermal Cancer Therapy Applications

Electromagnetics plays a crucial role in the interdisciplinary science of addressing the complex problem of targeted cancer therapy. Thermal therapies such as radio-frequency and microwave hyperthermia and ablation techniques though effective in ablating tumors are non-target specific. The dissertation focus on alternate thermal and non-thermal approaches inducing cancer cell apoptosis by external magnetic fields.

Nanoparticle based target specific rf hyperthermia is explored by designing an LCR resonator. Specific Absorption Rate (SAR) of the NPs are determined to quantify rf heat enhancement due to the presence of NPs. Interaction of all field components with the NPs and their heat loss origin are investigated to study the SAR discrepancy in literature. Through measurements and finite element method simulations we determine the interaction of axial electric field with the electric double layer at the NPs/protein/ions interface leads to the SAR overestimation. To improve efficiency of NP targeting, a thermal therapy targeting specific heat sensitive ion channels which overcomes the drawbacks of nanoparticle hyperthermia such as particle concentration is explored. A low frequency ferrite core LCR resonator was designed to characterize magnetic nanoparticles in strong magnetic field with improved focusing and selectivity.

A non-thermal approach to induce cancer cell death through mechanical stress on the cell membrane via external magnetic field gradients was developed. The mechanical force acting on the microenvironment of the cell, affects the cytoskeleton which in turn induces internal biochemical forces/interactions which cause apoptosis. Static and ac (sweeping) magnetic field gradient generator was designed to be placed in an incubator to study the effects of magnetic force on cancer cell line. Further, the cells are dosed with magnetic nanoparticles (MNPs) functioning as force enhancers due to the added rotational force under ac fields. The field distributions, magnetic field gradient strength are visualized through finite element method simulations of the static and ac magnetic field generator. Pancreatic adenocarcinoma cell line, AsPC-1 stained with DRAQ7 are exposed to the magnetic field gradients to observe cell viability.