Synthesis of Fe3O4-Au core-shell Nanoparticles with Eucalyptus

Nano-scaled materials have attracted interest during the last decade as they exhibit unique properties compared with bulk materials. In recent years, the synthesis of composite magnetic nanomaterials has received increasing attention because of their electronic, magnetic, catalytic and chemical or biological sensing properties. Currently, magnetic nanoparticles exhibit widespread applications in biotechnology, such as DNA and RNA acid purification cell separation, drug delivery, magnetic resonance imaging and hyperthermia cancer treatments. Coating magnetic nanoparticles with an external shell such as gold has been attempted in order to add new properties (protection of the magnetic core against oxidation) to those of the particles, without modifying their superparamagnetic behavior [1]. Although magnetic and metallic nanoparticles have been widely investigated, few works have been published on the development of a combined approach to achieve this composite material. Some methods which are used to obtain metal oxide core/Au shell magnetic nanoparticles contain reversed micelle system [2]. These systems are not suitable for biological applications because it is used harmful surfactants or organic solvents. Another researches tried to coat gold on surfaces of magnetic nanoparticles by biocompatible methods. According to Pham et al [3], Gold-coated magnetic nanoparticles were synthesized by using sodium citrates as the reducing agent. Similar magnetic core/shell structured or dumbbell-like particles of Au–Fe composition have been synthesized in microemulsions [4]. In this report, we synthesized magnetic nanoparticles by the method of Martinez et al [5]. For preparing Au-shell coating, it was used HAuCl4 as well as Eucalyptus to reduce Au3+ on the surface of Fe oxide. These nanoparticles can be used for medical applications Because Eucalyptus is vegetative and non-toxic agent.