Superparamagnetic iron oxide nanoparticles for MR imaging and therapy: design considerations and clinical applications

Superparamagnetic iron oxide nanoparticles (SPION) based magnetic resonance imaging (MRI) is a powerful non-invasive tool in biomedical imaging, clinical diagnosis and therapy. In this review, the physicochemical properties of SPION and their in vivo performance were thoroughly discussed, also covering how surface engineering will prolong the circulation time and overcome biological barriers at organ, tissue, and cellular levels. Clinical applications and future potentials of SPION based MR imaging in cancer, cardiovascular, and inflammation diseases were addressed. Targeting mechanisms of SPION in both research and clinical use were summarized for better understanding of their performance. Addition of new targeting mechanisms to clinically approved SPION will bring opportunities to discover early diseases at cellular and molecular levels, and to track MRI-visible drug carriers. Clinical trial information related to SPION on Clinicaltrials.gov was summarized mainly based on their disease categories, therapeutic applications and clinical trial stages. It gives us a brief outlook of their clinical applications in the near future.