Fig. 9

Quantification of the nanoparticles that accumulate in the liver and spleen over time. a, b After obtaining the magnetic susceptibility values from the spleen and liver, the amounts of the nanoparticles present after their administration was calculated, defining the degradation times of the three types of MNPs. For this, the susceptibility curves of each sample were compared with the known MNP standards, calculating the results per unit mass of tissue. c The total iron mass in the spleen and liver was quantified at different degradation times, obtaining the iron mass values from the out-of-phase magnetic susceptibility measurements of the complete spleen and part of the liver. The total iron mass in the liver was estimated from the total mass of this organ. The total iron content in the form of particles was similar in the liver and spleen for the APS-MNPs, whereas for the DEX- and DMSA-MNPs the total iron mass was larger in the liver than the spleen. d The total iron mass determined at different times (m_Fe) and normalized to the estimated mass at the first time point (\({\mathrm{m}}_{{\mathrm{Max}}_{7\mathrm{days}}}\)) for the liver and spleen. This relationship allowed the degradation speed of the particles in the different organs to be better visualized since the effect of the initial accumulation of particles in the tissues was normalized. The data are shown as the means ± SD (n = 3)