Size-selected Fe3O4-Au hybrid nanoparticles for improved magnetism-based theranostics.

Maria V Efremova,Natalia L Klyachko,Alexander G Majouga,Eirini Myrovali,Marina Spasova,Ivan S Grebennikov,Makis Angelakeris,Anastasiia S Garanina,Alexander G Savchenko,Yulia A Nalench,Ulf Wiedwald,Polina K Gifer,Michael Farle,Maxim A Abakumov

doi:10.3762/bjnano.9.251

Abstract

Size-selected Fe3O4–Au hybrid nanoparticles with diameters of 6–44 nm (Fe3O4) and 3–11 nm (Au) were prepared by high temperature, wet chemical synthesis. High-quality Fe3O4 nanocrystals with bulk-like magnetic behavior were obtained as confirmed by the presence of the Verwey transition. The 25 nm diameter Fe3O4–Au hybrid nanomaterial sample (in aqueous and agarose phantom systems) showed the best characteristics for application as contrast agents in magnetic resonance imaging and for local heating using magnetic particle hyperthermia. Due to the octahedral shape and the large saturation magnetization of the magnetite particles, we obtained an extraordinarily high r2-relaxivity of 495 mM−1·s−1 along with a specific loss power of 617 W·gFe−1 and 327 W·gFe−1 for hyperthermia in aqueous and agarose systems, respectively. The functional in vitro hyperthermia test for the 4T1 mouse breast cancer cell line demonstrated 80% and 100% cell death for immediate exposure and after precultivation of the cells for 6 h with 25 nm Fe3O4–Au hybrid nanomaterials, respectively. This confirms that the improved magnetic properties of the bifunctional particles present a next step in magnetic-particle-based theranostics.

Highlights

Biocompatible magnetite nanoparticles (NPs) are anticipated to provide new noninvasive therapies and early diagnostics for previously incurable diseases using a single, so-called “theranostics” platform [1,2,3]
This is followed by a discussion of the theranostic application of NPs in magnetic resonance imaging (MRI) and magnetic particle hyperthermia (MPH)
We present the first size-dependent study of hybrid Fe3O4–Au NPs with Janus structure for application in theranostics where improvements in MRI and MPH were demonstrated

Summary

Introduction

Biocompatible magnetite nanoparticles (NPs) are anticipated to provide new noninvasive therapies and early diagnostics for previously incurable diseases using a single, so-called “theranostics” platform [1,2,3]. The r2 values of the Fe3O4–Au hybrid samples were measured for all particle sizes (Figure 5, Figure S3, Supporting Information File 1) in water and in 2% agarose NP solutions.

Results

Conclusion