Preparation method of core-shell magnetic/gold nano particles

Abstract

The invention discloses a preparation method of magnetic/gold nano particles. The preparation method comprises the following steps: firstly adopting a co-precipitation method to prepare the magnetic Fe3O4 nano particles; polymerizing the dopamine in-situ on the surfaces of the magnetic particles to obtain Fe3O4 nano particles modified by the poly dopamine; introducing polyphenol and amino groups to the surfaces of the Fe3O4 nano particles; absorbing the nano gold seeds on the surfaces of the modified magnetic particles through the static action; adopting the nano gold which is absorbed on the surfaces of the magnetic particles as the seed, adopting the polyphenol on the surfaces of the magnetic particles as a reducing agent, gradually adding the chloroauric acid liquid to gradually produce the gold layers on the surfaces of the magnetic particles to obtain the core-shell magnetic/gold nano particles. The nano particles have good water dispersion and strong magnetic respond performance. The diameters of the nano particles are 30-100 nanometers, the saturation magnetization is 30.1-38.7emu/g, and the nano particles are superparamagnetic. The nano particles have wide application prospect on the fields of targeted drug controlled release, thermal therapy, separation of protein and enzyme, etc.

Description

technical field [0001] The invention belongs to the field of nanocomposite materials, and in particular relates to the preparation of gold magnetic nanoparticles (namely, ferric oxide magnetic core-coated outer gold shell nanoparticles). Background technique [0002] Magnetic nanoparticles have the characteristics of magnetic field responsiveness, nano-size effect, low toxicity and biocompatibility, which make them widely used in many fields. Magnetic nanoparticles provide many possibilities for life science and biotechnology, and have a wide range of applications in bioseparation, targeted drug delivery, hyperthermia, and magnetic resonance imaging. In addition, in the field of catalysis, using it as a catalyst carrier can not only greatly improve the activity of the catalyst, but also facilitate the recovery and reuse of the catalyst. However, magnetic nanoparticles are easily oxidized to reduce their magnetic properties, and the surface is not easy to modify. A layer of...

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Problems solved by technology

The core-shell particles prepared by this method have poor dispersibility, and it is difficult to obtain evenly coated particles. In addition, most of the reducing agents added are toxic.

Patent CN1736881 reported the preparation of sodium citrate-coated nano Fe by co-precipitation 3 o 4 Particles, and then use it as a seed crystal, under boiling conditions, reduce chloroauric acid with sodium citrate to obtain core-shell magnetic / gold nanoparticles, the nano-Fe obtained by this method 3 o 4 Particles are easily oxidized and magnetically reduced under boiling conditions, and the dispersion of the prepared nanoparticles is not good

Later, the seed-mediated method was adopted, that is, the surface of the magnetic nanoparticles was first modified so that the surface of the particles could be positively charged, and then the negatively charged nano-gold seeds were loaded on the magnetic nanoparticles through electrostatic attraction, so that the seeds As the growth center, core-shell particles are obtained by successively adding chloroauric acid and reducing agent aqueous solution. Although the particle coating obtained by this method is more regular, the preparation process is more complicated.

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