Water-Soluble Anisotropic Iron Oxide Nanoparticles: Dextran-Coated Crystalline Nanoplates and Nanoflowers

Abstract

We report a simple phase transfer based synthesis route for two novel anisotropic water soluble iron oxide nanoparticle shapes, namely, nanoplates and nanoflowers. The nanoplates and nanoflowers are initially prepared in an organic solvent via a modified “heat-up” method. Then, the crystalline nanoparticles are rendered hydrophilic via sonication in the presence of dextran and water. These nanoparticles are highly monodisperse and superparamagnetic at room temperature. High resolution transmission electron microscopy indicates that the iron oxides cores are not affected by the phase transfer. Dextran coating is confirmed by dynamic light scattering, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The obtained dextran coverage was 26 wt% for the nanoplates and 37 wt% for the nanoflowers. The nanoplates and nanoflowers were not only water soluble, but also remained stable at different pH (4–7) and in common aqueous buffer solutions. Thorough characterizations of the nonspherical iron oxide nanoparticles indicate that these particles could be useful for potential biomedical applications and magnetic resonance imaging.

Keywords:

• Materials
• nanoparticles
• nonspherical particle
• particle characteristics
• particle shape

Acknowledgments

We acknowledge Yale Institute of Nanoscience and Quantum Engineering (YINQE) for TEM facilities. We thank Elias Quijano and Dr. Saltzman for use of the DLS. Thanks are due to Teng-hooi Goh and Dr. Andre Taylor for use of the TGA. We also acknowledge the Chemical and Biophysical Instrumentation and specifically Dr. Wuyi Meng at Yale for FTIR and XRD2 facilities.

Notes

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/upst.