Hollow magnetic nanoparticles: synthesis and applications in biomedicine

Magnetic hollow particles (MHP) are widely used in biomedicine field due to their biocompatibility, low-toxicity, low-density and the large fraction void space in the MHP, which have been successfully used to encapsulate and control drugs release, and magnetic resonance imaging (MRI). This review focuses on all kinds of MHP preparation method, compares the advantages and disadvantages in the process of synthesis, and introduces especially the special formation mechanisms such as the Kirkendall effect and Ostwald ripening. Both the compatible interior space and good magnetism of magnetic hollow structures enable them promising and unique candidates as biomedicine vehicles. Particularly, the progress of MHP widely used in the biomedical engineering applications containing drug delivery and magnetic resonance imaging are described. The main problems and the directions in the future researches are pointed out.