Galvanic Displacement Synthesis of Monodisperse Janus- and Satellite-Like Plasmonic-Magnetic Ag-Fe@Fe3O4 Heterostructures with Reduced Cytotoxicity.

Huilin Zhang,Yanglong Hou,Yanmin Ju,Xintai Su,Xin Chu,Tianyu Tang,Ya Ding,Kai Zhu,Ziyu Yang,Xiaoxiao Huang

doi:10.1002/advs.201800271

Abstract

The unique physicochemical properties of silver nanoparticles offer a large potential for biomedical application, however, the serious biotoxicity restricts their usage. Herein, nanogalvanic couple Ag–Fe@Fe3O4 heterostructures (AFHs) are designed to prevent Ag+ release from the cathodic Ag by sacrificial anodic Fe, which can reduce the cytotoxicity of Ag. AFHs are synthesized with modified galvanic displacement strategy in nonaqueous solution. To eliminate the restriction of lattice mismatch between Fe and Ag, amorphous Fe@Fe3O4 nanoparticles (NPs) are selected as seeds, meanwhile, reductive Fe can reduce Ag precursor directly even at as low as 20 °C without additional reductant. The thickness of the Fe3O4 shell can influence the amorphous properties of AFHs, and a series of Janus‐ and satellite‐like AFHs are synthesized. A “cut‐off thickness” effect is proposed based on the abnormal phenomenon that with the increase of reaction temperature, the diameter of Ag in AFHs decreases. Because of the interphase interaction and the coupling effect of Ag and Fe@Fe3O4, the AFHs exhibit unique optical and magnetic properties. This strategy for synthesis of monodisperse heterostructures can be extended for other metals, such as Au and Cu.

Highlights

The unique physicochemical properties of silver nanoparticles offer a large topological structure.[1]
When the fresh prepared AgOA meets the Fe@Fe3O4 in solution, the recovered Ag just attached on the amorphous surface of the Fe@Fe3O4 NPs, resulting in the Janus-like Ag–Fe@ Fe3O4 heterostructures (JAFHs)
Note that if the inert atmosphere is introduced and kept throughout the reaction, another structure distinguished from Janus one, i.e., the satellite-like Ag–Fe@Fe3O4 heterostructures (SAFHs) with several Ag NPs distributed on the surface of Fe@Fe3O4 NPs can be obtained

Summary

Introduction

The unique physicochemical properties of silver nanoparticles offer a large topological structure.[1]. To eliminate the restriction provide an efficient way for the modulation of the physical and chemical properties of the heterostructures.[2] Among these properties, magnetic and optical properties can be efficiently controlled due to the synerof lattice mismatch between Fe and Ag, amorphous Fe@Fe3O4 nanoparticles gistic effect and coupling effect.[3]. Because of the interphase potential applications in various fields such interaction and the coupling effect of Ag and Fe@Fe3O4, the AFHs exhibit unique optical and magnetic properties. This strategy for synthesis of monodisperse heterostructures can be extended for other metals, such as Au and Cu. as multimodal imaging, targeting cancer therapy, and recyclable catalysis.[4]. Compared due to the multifunctional properties from the superpo- with the widely studied Au-based NPs, Ag-based NPs are seldom sition of each counterpart, and the synergistic effect of the used in biomedical field, except for antimicrobial, mainly due to

Methods

Results

Conclusion