Erik M. Shapiro1,
Michael K. Nkansah2
1Department
of Radiology, Michigan State University, East Lansing, MI, United States; 2Department
of Biomedical Engineering, Yale University, New Haven, CT, United States
Magnetic particles are a key technology behind MRI-based cell tracking. We describe the first characterization of in vivo biodegradation rate of a specifically designed magnetic nanoparticle dedicated for magnetic cell labeling. PLGA-encapsulated magnetic nanoparticles, ~ 100 nm @ 84% iron weight were injected intravenously into mice. Inert MPIOs and Feridex, were also injected into additional mice. Serial MRI of the liver over 12 weeks revealed that Feridex was rapidly degraded within two weeks while inert MPIOs exhibited no biodegradation. 2:1 NPs exhibited an intermediate biodegradation rate, with 80% clearance of the iron at the end of 12 weeks.