Figure 2.

Schematic illustration of magnetic left-then-right shift option to increase nanoparticle levels into and throughout liver metastatic tumor foci. Left and right panels: appropriately chosen (strong and correctly sized) magnets can create sufficient magnetic gradients on therapeutic magnetic nanoparticles to displace them from dense distributions in normal tissue into adjacent poorly vascularized tumor regions. In this example, magnetic shift is shown in just two successive directions, but the process can be repeated in multiple spatial planes. Middle panel: computer simulations of the resulting therapeutic particle distributions in a 1 mm-wide tissue region using blood vessel geometry taken from autopsy data (gray markings). The color gradient shows the resulting nanoparticle concentration at each tissue location (red is high, white is low). Magnetic actuation increases nanoparticle concentration in the tumor area (marked by the black circle, also clearly visible by a lack of blood vessels) at 30, 60, 120, and 180 minutes after systemic injection.