Designed synthesis and assembly of uniform-sized iron oxide nanoparticles for multifunctional medical applications

We developed a generalized synthetic procedure, called heat-up process, to produce uniform-sized iron oxide nanocrystals with controlled sizes ranging from 1.5 nm to 100 nm [1–4]. High resolution blood pool magnetic resonance (MR) imaging using uniform 3 nm-sized iron oxide nanoparticles enabled clear observation of various blood vessels with sizes down to 0.2 mm [5]. We used 80 nm-sized ferrimagnetic iron oxide nanocrystals for T2 MRI contrast agent for tracking transplanted pancreatic islet cells and single-cell MR imaging [6]. Clever combination of different nanoscale materials will lead to the development of multifunctional nano-biomedical platforms for simultaneous targeted delivery, fast diagnosis, and efficient therapy [7]. In this presentation, I would like to present some of our group´s recent results on the designed fabrication of multifunctional nanostructured materials based on uniform-sized magnetite nanoparticles and their bio-medical applications. We reported on the fabrication of monodisperse magnetite nanoparticles immobilized with uniform pore-sized mesoporous silica spheres for simultaneous MRI, fluorescence imaging, and drug delivery [8, 9]. We synthesized hollow magnetite nanocapsules and used them for both the MRI contrast agent and magnetic guided drug delivery vehicle [10]. We reported the fabrication of novel alginate capsule-in-capsules (CICs) containing iron oxide and gold nanoparticles and human pancreatic islets for simultaneous immunoprotection and multimodal imaging [11].