An update on the applications and characteristics of magnetic iron oxide nanoparticles for drug delivery.

INTRODUCTION: In the field of drug delivery, controlling the release of therapeutic substances at localized targets has become a primary focus of medical research, especially in the field of cancer treatment. Magnetic nanoparticles are one of the most promising drug carriers thanks to their biocompatibility and (super)paramagnetic properties. These properties allow for the combination between imaging modalities and specific release of drugs at target sites using either local stimulus (i.e. pH, conjugation of biomarkers, …) or external stimulus (i.e. external magnetic field). AREAS COVERED: This review provides an update on recent advances with the development of targeted drug delivery systems based on magnetic nanoparticles (MNPs). This overview focuses on active targeting strategies and systems combining both imaging and therapeutic modalities (i.e. theranostics). If most of the examples concern the particular case of cancer therapy, the possibility of using MNPs for other medical applications is also discussed. EXPERT OPINION: The development of clinically relevant drug delivery systems based on magnetic nanoparticles is driven by advantages stemming from their remarkable properties (i.e. easy preparation, facile chemical functionalization, biocompatibility, low toxicity, and superior magnetic responsiveness). This literature review shows that drug carriers based on magnetic nanoparticles can be efficiently used for the controlled release of drug at targeted locations mediated by various stimuli. Advances in the field should lead to the implementation of such systems into clinical trials, especially systems enabling drug tracking in the body.

VSION as high field MRI T1 contrast agent: evidence of their potential as positive contrast agent for magnetic resonance angiography.

Because of their outstanding magnetic properties, iron oxide nanoparticles have already been the subject of numerous studies in the biomedical field, in particular as a negative contrast agent for T2-weighted nuclear magnetic resonance imaging, or as therapeutic agents in hyperthermia experiments. Recent studies have shown that below a given particle size (i.e. 5 nm), iron oxide may be used to provide a significant positive (brightening) effect on T1-weighted MRI. In such an application, not only the size of the crystal, but also the control of the coating process is essential to ensure optimal properties, especially at a very high field (> 3 T). In this work, we focused on the development of very small iron oxide nanoparticles as a potential platform for high field T1 magnetic resonance angiography (MRA) applications. The feasibility has been evaluated in vivo at 9.4 T, demonstrating the usefulness of the developed system for MRA applications.