The fate of magnetic nanoparticles after intratumoral injection

Abstract

In recent years, there has been significant research focusing on the use of magnetic nanoparticles for biomedical applications. To date, most of this research has focused on the development of the particles, their surface functionalization and the experiments leading to the proof of concept of the different biomedical applications. However, before these particles reach the clinical practice, several aspects regarding their biological fate, biodistribution, and toxicity, must be assessed. Previous research on the biodistribution and degradation of magnetic nanoparticles after systemic administration has shown that nanoparticles accumulate mainly in the spleen and liver of animals and that the degradation kinetics of magnetic nanoparticles may be very slow. However, there is little information regarding the biodistribution of magnetic nanoparticles when different administration routes are used. In this study, we have evaluated the degradation and biodistribution of magnetic nanoparticles after intratumoral injection. We have used a human pancreatic heterotopic-xenograft tumour model in Balb/c nude mice. Animals received a single intratumoral administration of magnetic nanoparticles. The migration of the particles to other organs was evaluated in two different scenarios: one in which no further treatment was applied to the animals and other in with an alternating magnetic field for hyperthermia treatment was applied three times along a week. The biodistribution and degradation over time of the particles has been followed by AC magnetic susceptibility. These experiments have allowed us to evaluate the effect of the magnetic hyperthermia treatment on the nanoparticles biodistribution.