Influence of Magnetic Nanoparticle Degradation in the Frame of Magnetic Hyperthermia and Photothermal Treatments

This work aims at studying how the transformations that magnetic nanoparticles suffer in vivo affect their heating properties in the frame of hyperthermia treatments. Iron oxide magnetic nanoparticles (approximate to 13 nm) with two different coatings [PMAO (polymaleic anhydride-alt-1-octadecene) and DMSA (dimercaptosuccinic acid)] have been subjected to an accelerated degradation in a medium simulating lysosome conditions. The particles physicochemical properties (size, size distribution, and magnetic properties) have been followed over the degradation process along 24 days. It was found that DMSA-coated particles degraded much faster than PMAO-coated ones. In addition, their heating properties under both the exposure to an alternating magnetic field or a near infrared light have been tracked along this degradation processes, assessing how the changes in their physicochemical properties affect their heating capacity. Along the degradation procedure, a stronger decrease of the particles heating properties has been observed in the frame of magnetic hyperthermia measurements, in comparison with the photothermal ones. Finally, the PMAO-coated particles have been selected for a degradation study in vivo after intratumoral administration. Interestingly, although the number of particles decreases with time in the tissue, the size and size distribution of the particles do not change significantly over time. This work is especially relevant in the frame of the design of in vivo hyperthermia treatments using magnetic nanoparticles as it would provide fundamental clues regarding the need of repeated doses or the possible use of a single administration depending on the treatment duration.

Automated summary

This study investigates how the transformations of magnetic nanoparticles in vivo affect their heating properties in hyperthermia treatments. Iron oxide magnetic nanoparticles with two different coatings were subjected to accelerated degradation to simulate lysosome conditions. The degradation process was monitored for 24 days, revealing that DMSA-coated particles degraded faster than PMAO-coated ones. Changes in physicochemical properties were found to impact the heating capacity under an alternating magnetic field or near infrared light. Additionally, intratumoral administration of PMAO-coated particles showed no significant changes in size and size distribution over time. This research is particularly relevant for the design of in vivo hyperthermia treatments using magnetic nanoparticles.