Self-Assembly of Au-Fe3O4 Hybrid Nanoparticles Using a Sol-Gel Pechini Method.

Jesus G Ovejero,Pilar Herrasti,Miguel A Garcia

doi:10.3390/molecules26226943

Jesus G Ovejero, Pilar Herrasti + Show 1 more

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https://doi.org/10.3390/molecules26226943

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Abstract

The Pechini method has been used as a synthetic route for obtaining self-assembling magnetic and plasmonic nanoparticles in hybrid silica nanostructures. This manuscript evaluates the influence of shaking conditions, reaction time, and pH on the size and morphology of the nanostructures produced. The characterization of the nanomaterials was carried out by transmission electron microscopy (TEM) to evaluate the coating and size of the nanomaterials, Fourier-transform infrared spectroscopy (FT-IR) transmission spectra to evaluate the presence of the different coatings, and thermogravimetric analysis (TGA) curves to determine the amount of coating. The results obtained show that the best conditions to obtain core–satellite nanostructures with homogeneous silica shells and controlled sizes (<200 nm) include the use of slightly alkaline media, the ultrasound activation of silica condensation, and reaction times of around 2 h. These findings represent an important framework to establish a new general approach for the click chemistry assembling of inorganic nanostructures.

Highlights

Magneto-plasmonic nanoparticles (NPs) are a revolutionary family of nanostructures that combine phases with a ferromagnetic response and metallic phases with free electrons that can be optically excited as a surface plasmon resonance [1,2]
The Pechini sol–gel method studied in this article creates magneto-plasmonic hybrid nanostructures by combining iron oxide nanoparticles (IONPs) and Au nanorods (AuNRs) prepared with tetrabutylammonium bromide (TBAB) and hexadecyltrimethylammonium bromide (CTAB) coatings, respectively
The CTAB used in the synthesis of AuNRs (Figure 1a) acts as an organic template that shapes the growth of the crystal facets to generate an average length of 39.7 nm (σ = 0.14) and an average diameter of 12.1 nm (σ = 0.21) that result in an aspect ratio of 3.4 (σ = 0.23)

Summary

Introduction

Magneto-plasmonic nanoparticles (NPs) are a revolutionary family of nanostructures that combine phases with a ferromagnetic response and metallic phases with free electrons that can be optically excited as a surface plasmon resonance [1,2]. The possibilities that these nanostructures offer to the biomedical field in terms of dual contrast agents [3], theragnostic agents [4], or biosensing [5] are countless. Single-phase NPs with good magnetic properties are generally bad conductors and vice versa [2] For this reason, there is great urgency to develop new synthetic methods to create multicomponent NPs in which magnetic and plasmonic phases can be combined [6,7]. The use of organic–inorganic interactions through click chemistry techniques appear to be the best solution to assemble inorganic phases with minimal disturbance of their individual properties [8].

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