Precise Study on Size-Dependent Properties of Magnetic Iron Oxide Nanoparticles for In Vivo Magnetic Resonance Imaging

Ling Chen,Jianzhong Li,Fengchao Zang,Ning Gu,Yu Zhang,Jun Xie,Haoan Wu,Lina Song,Zhiming Wang,Ming Ma

doi:10.1155/2018/3743164

Abstract

Developing a biocompatible contrast agent with high stability and favorable magnetism for sensitive detection of malignant tumors using magnetic resonance imaging (MRI) remains a great demand in clinical. Nowadays, the fine control of magnetic iron oxide nanoparticle (MION) sizes from a few nanometers to dozens of nanometers can be realized through a thermal decomposition method of iron precursors. This progress allows us to research accurately on the size dependence of magnetic properties of MION, involving saturation magnetization (Ms), specific absorption rate (SAR), and relaxivity. Here, we synthesized MION in a size range between 14 and 26 nm and modified them with DSPE-PEG2000 for biomedical use. The magnetic properties of PEGylated MION increased monotonically with MION size, while the nonspecific uptake of MION also enhanced with size through cell experiments. The MION with the size of 22 nm as a T2-weighted contrast agent presented the best contrast-enhancing effect comparing with other sizes in vivo MRI of murine tumor. Therefore, the MION of 22 nm may have potential to serve as an ideal MRI contrast agent for tumor detection.

Highlights

Over the past few decades, numerous researches have focused on nanomaterials for biomedical applications, among which magnetic iron oxide nanoparticles (MIONs) have become the most promising candidate owing to their excellent biocompatibility and outstanding magnetic properties
We report a precise study on size-dependent properties of MION synthesized by a thermal decomposition method capable of yielding nanoparticles in a size range between 14 and 26 nm as a T2-weighted contrast agent for magnetic resonance imaging (MRI)
Our study demonstrated that the properties of MION such as Ms, specific absorption rate (SAR), and r2 relaxivity were all dependent on size and enhanced monotonically with MION size from 14 to 26 nm

Summary

Introduction

Over the past few decades, numerous researches have focused on nanomaterials for biomedical applications, among which magnetic iron oxide nanoparticles (MIONs) have become the most promising candidate owing to their excellent biocompatibility and outstanding magnetic properties. Several iron oxide nanoparticles including Feridex and Resovist have been approved as contrast agents for T2-weighted MR imaging in clinical for years Due to their synthetic method of coprecipitation, the products are polydisperse with low crystallinity, which results in relatively inferior magnetic properties. The interaction between particles enhanced with their size increased, which will result in aggregation and instability in solution Owing to these reasons, this study will focus on MION with size from 14 to 26 nm for suitable in vivo applications used as MRI contrast agents. We report a precise study on size-dependent properties of MION synthesized by a thermal decomposition method capable of yielding nanoparticles in a size range between 14 and 26 nm as a T2-weighted contrast agent for MRI. The size of 22 nm may be the most appropriate selection used for in vivo MRI

Experimental

Synthesis of Size-Controlled Magnetic Iron Oxide

Results and Discussion

Conclusion