FIGURE 5.

A safe number of magnetic nanoparticles induces a detectable voltage signal. (A) The relationship between coil sensitivity and the mass of magnetic nanoparticles (MNPs) required to produce a detectable voltage signal. Detection limits are shown for different voltmeter sensitivities along with the placement of the coil. Assuming one arterial pulse passes through the coil for each timestep, the difference in mass of MNPs needed for detection was calculated for a pulse volume in the forearm and leg, respectively. The green shaded area represents the safe range of the MNP mass, the pink shaded area represents the toxic range, and the transition region is potentially toxic. (B) The number of MNPs needed to induce a detectable voltage signal as a function of coil sensitivity for different particle radii. Data points indicate how particle size influences the required MNP quantity.