Synthesis, transfer, and characterization of core-shell gold-coated magnetic nanoparticles

Mckenzie Smith,Maureen Mckeague,Maria C Derosa

doi:10.1016/j.mex.2019.02.006

Mckenzie Smith, Maureen Mckeague + Show 1 more

Open Access

https://doi.org/10.1016/j.mex.2019.02.006

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Journal: MethodsX	Publication Date: Jan 1, 2019
Citations: 30	License type: cc-by

Affiliation: Carleton University, McGill University

Abstract

Magnetic separation has gained new popularity as a versatile partitioning method with the recent growth in nanotechnology and related biotechnology applications. In this study, iron oxide magnetic nanoparticles were synthesized via solvothermal methods and directly coated with gold to form core-shell gold-coated magnetic nanoparticles (Fe3O4-AuNPs). High-resolution transmission electron microscopy with Energy dispersive X-ray spectroscopy results suggests that temperature and reaction time play an important role in the formation of small, monodisperse Fe3O4-AuNPs. We also demonstrate that increased 4- dimethyl(amino)pyridine (DMAP) concentrations and vigorous stirring were required to successfully transfer Fe3O4-AuNPs into aqueous solution. The structure and morphology of the synthesized and transferred Fe3O4-AuNPs was further confirmed by UV–vis absorption spectroscopy and solubility experiments.•Direct coating of Fe3O4 with Au: Slowly heating by (10 °C/ min) until 180–190 °C without exceeding this reaction temperature and increasing the reaction time to 3 h from 1.5 h•High yield transfer of Fe3O4-AuNPs was achieved using 4- dimethyl(amino)pyridine (DMAP) as phase transfer catalyst

Highlights

Sun and Zeng report the synthesis of size-controlled magnetite nanoparticles through a solvothermal method where Fe(acac)3 is reduced by 1,2-hexadecanediol in the presence of two capping agents [31,33]
When the solution was heated to the boiling point of phenyl ether (258 C) for 2 h, the size distribution of the synthesized magnetite nanoparticles was quite extensive (Fig. S1.) Alternatively, when the temperature of the solution was heated to 210 C, as was suggested by Wang et al, the size distribution of the synthesized magnetite nanoparticles was narrowed producing more monodisperse Fe3O4 NPs [32]
We found that failing to precisely increase the reaction temperature led to the formation of separate AuNPs, or an inconsistent gold shell, in the presence of Fe3O4 NPs