Cell death via remote heating of microparticles with potential applications in atherosclerosis and thrombosis therapy

We report a method to cause cell death by remotely heating microparticles by induction heating, this technique could be used to remove vascular deposits and thrombosis. In this preliminary work, we used micrometer size spherical (ferromagnetic) particles and (pure) iron particles to heat remotely macrophages using inductive heating. Iron particles achieved maximum temperatures of 51 ± 0.5 oC after 30 minutes of inductive heating, while spherical particles achieved a maximum temperature of 43.9 ± 0.2 oC (N=6). The therapeutic outcome was determined by monitoring cell re-growth for 2 days following inductive heating treatment. The initial density of cells in the first day prior to induction heating was 105,000 ± 20,820 cells/ml (N=3). 24 hours after induction heating this number was reduced to 6,666 ± 4,410 cells/ml for the spherical particles and 16,666 ± 9,280 cells/ml for the iron particles. The second day the cells grew to 26,667 ± 6,670 cells/ml and 30,000 ± 15,280 cells/ml respectively. Compared to cell cultures with iron and spherical particles that were not subjected to induction heating, we observed a 97% reduction in cell count for the spherical particles and a 91% reduction for the iron particles after the first 24 hours. After 48 hours we observed a 95% reduction in cell growth for both spherical and iron particles. Induction heating of microparticles was highly effective in reducing the macrophage population and preventing their growth.