Quantitative Drug Release Monitoring in Tumors ofLiving Subjects by Magnetic Particle Imaging Nanocomposite

In vivo drug release monitoring provides accurate and reliable information to guide drug dosing. Image-based strategies for in vivo monitoring are advantageous because they are non-invasive and provide visualization of the spatial distribution of drug, but those imaging modalities in use (e.g., fluorescence imaging (FI) and magnetic resonance imaging (MRI)) remain inadequate because of the low tissue penetration depth (for FI) or difficulty with quantification of release rate and signal convolution with noise sources (for MRI). Magnetic particle imaging (MPI), employing superparamagnetic nanoparticles as the contrast agent and sole signal source, enables large tissue penetration and quantifiable signal intensity. These properties make it ideal for application to in vivo drug release monitoring. In this work, we design a superparamagnetic Fe3O4 nanocluster@poly(lactide-co-glycolide acid) core–shell nanocomposite loaded with a chemotherapy drug (doxorubicin) which serves as a dual drug delivery system and M...