In recent years, apllications of magnetic nanomaterials in molecular imaging have attracted much attention. The superparamagnetic nanoparticle is the most popular magnetic nanoparticle due to its good T₂-weighted magnetic resonance imaging (MRI) contrast agent property. With the improvement of preparation and surface modification method, the superparamagnetic iron oxide particles (SPION) has been applied to imaging contrast, stem cell labeling and drug/gene delivery. This article reviews the combined applications of SPION in imaging contrast and MRI guided treatment. It also points out that many kinds of magnetic nanomaterials used for biomedical applications have low imaging contrast and specificity in vivo and have negative effecton living organism, which hinder the clinical application of SPION. Combined with the current public concerns and development of nanomedicine preparation methods, the preparation of SPION with good MRI contrast effect, high biocompatibility, disease area targeting and clinical conversion potential is a challenge to deal with in the new generation of magnetic nano-probes.

magnetic nanomaterials  /  magnetic resonance imaging  /  molecular probes  /  theranostics