Magnetoresponsive Therapy Nohyun Lee, Dongwon Yoo, Daishun Ling,†,‡,⊥ Mi Hyeon Cho, Taeghwan Hyeon,*,†,‡ and Jinwoo Cheon* †Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, Korea ‡School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea Department of Chemistry, Yonsei University, Seoul 120-749, Korea School of Advanced Materials Engineering, Kookmin University, Seoul 136-702, Korea Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, PR China

Iron Oxide Based Nanoparticles for Multimodal Imaging and Magnetoresponsive Therapy.

Organic/inorganic nanohybrids have attracted widespread interests due to their favorable properties and promising applications in biomedical areas. Great efforts have been made to design and fabricate versatile nanohybrids. Among different organic components, diverse polymers offer unique avenues for multifunctional systems with collective properties. This review focuses on the design, properties, and biomedical applications of organic/inorganic nanohybrids fabricated from inorganic nanoparticles and polymers. We begin with a brief introduction to a variety of strategies for the fabrication of functional organic/inorganic nanohybrids. Then the properties and functions of nanohybrids are discussed, including properties from organic and inorganic parts, synergistic properties, morphology-dependent properties, and self-assembly of nanohybrids. After that, current situations of nanohybrids applied for imaging, therapy, and imaging-guided therapy are demonstrated. Finally, we discuss the prospect of organic/in...

Versatile Types of Organic/Inorganic Nanohybrids: From Strategic Design to Biomedical Applications.

Magnetic iron oxide nanoparticles (MIONs) have attracted enormous attention due to their wide applications, including for magnetic separation, for magnetic hyperthermia, and as contrast agents for magnetic resonance imaging (MRI). This review article introduces the methods of synthesizing MIONs, and their application as MRI contrast agents. Currently, many methods have been reported for the synthesis of MIONs. Herein, we only focus on the liquid-based synthesis methods including aqueous phase methods and organic phase methods. In addition, the MIONs larger than 10 nm can be used as negative contrast agents and the recently emerged extremely small MIONs (ES-MIONs) smaller than 5 nm are potential positive contrast agents. In this review, we focus on the ES-MIONs because ES-MIONs avoid the disadvantages of MION-based T2- and gadolinium chelate-based T1-weighted contrast agents.

Iron Oxide Nanoparticle Based Contrast Agents for Magnetic Resonance Imaging.

Ultrasmall inorganic nanoparticles: State-of-the-art and perspectives for biomedical applications.

Ultrasmall biocompatible WO3 - x nanodots with an outstanding X-ray radiation sensitization effect are prepared, and demonstrated to be applicable for multi-modality tumor imaging through computed tomography and photoacoustic imaging (PAI), and effective cancer treatment combining both photothermal therapy and radiation therapy.

Ultrasmall Biocompatible WO3- x Nanodots for Multi-Modality Imaging and Combined Therapy of Cancers.

Monodispersed water-soluble and biocompatible ultrasmall magnetic iron oxide nanoparticles (UMIONs, D = 3.3 +/- 0.5 nm) generated from a high-temperature coprecipitation route are successfully used as efficient positive and negative dual contrast agents of magnetic resonance imaging (MRI). Their longitudinal relaxivity at 4.7 T (r1 = 8.3 mM-1 s-1) is larger than that of clinically used T1-positive agent Gd-DTPA (r1 = 4.8 mM-1 s-1), and three times that of commercial contrast agent SHU-555C (r1 = 2.9 mM-1 s-1). The transversal relaxivity (r2 = 35.1 mM-1 s-1) is six times that of Gd-DTPA (r2 = 5.3 mM-1 s-1), half of SHU-555C (r2 = 69 mM-1 s-1). The in vivo results show that the liver signal from T1-weighted MRI is positively enhanced 26%, and then negatively decreased 20% after injection of the iron oxide nanoparticles, which is stronger than those obtained from Gd-DTPA (<10%) using the same dosage. The kidney signal is positively enhanced up to 35%, similar to that obtained from Gd-DTPA. Under T2-weighted conditions, the liver signal is negatively enhanced ?70%, which is significantly higher than that from Gd-DTPA (?6%). These results demonstrate the great potential of the UMIONs in dual contrast agents, especially as an alternative to Gd-based positive contrast agents, which have risks of inducing side effects in patients.

Ultrasmall Water-Soluble and Biocompatible Magnetic Iron Oxide Nanoparticles as Positive and Negative Dual Contrast Agents

Reducing ferromagnetic particle size is an important strategy to improve their positive effect on imaging through the suppression of their negative effect, demonstrated by ultrasmall manganese ferrite nanoparticles prepared from an environmentally-friendly aqueous route. These ultrasmall particles exhibit pronounced paramagnetic characteristics and nontoxicity, making them efficient T1-positive contrast agent and manganese contrast agents for manganese enhanced MRI.

Hong Li Zhao

Papers

Ultrasmall Water-Soluble and Biocompatible Magnetic Iron Oxide Nanoparticles as Positive and Negative Dual Contrast Agents

Ultrasmall manganese ferrite nanoparticles as positive contrast agent for magnetic resonance imaging.