## 1 Introduction  
Nanotechnology and nanoscience involve the ability to manipulate matter with at least a dimension between 1 and 100 nanometers being related to imaging, measure, and model, but also to the improvement of materials and applications by exploring their unique properties exposed at the nanometric scale [1]. Over the past decade, nanotechnology has been integrated into medicine and biology by developing a new active and significant research area, nanomedicine, which was materialized in clinical applications such as diagnosis and therapy, having many perspectives to broaden these applications and to extend them from lab to clinic [2; 3]. In this new area of interest, nanobiotechnology approaches have been used in developing core/shell nanostructures of different functionalities. The most common materials used for biomedical applications were superparamagnetic nanoparticles and, especially, magnetite nanoparticles because of their unique properties that will be explained in this review [4]. Nanotechnology offers nano dimensioned materials such as nanoparticles, nanotubes, nanowires, thin films, and nanocomposites functionalized or coated on a specific surface to obtain different nanomaterials that can be useful in many applications [4; 5]. As drug delivery platforms, nanoparticles would be able to load bio-therapeutic agents and dissolve in any environment with great potential in biomedical applications, such as cancer diagnosis and therapy [1; 4; 5]. For in vivo applications of nanoparticles, certain properties need to be considered, such as surface morphology, chemistry, and molecular weight. Depending on the materials used and the structure of the materials in the nanoparticles, we classify them into distinct groups, such as polymeric nanoparticles, lipid nanoparticles, liposomes, polymeric micelles, quantum dots, dendrimers, metallic nanoparticles, carbonaceous materials, core/shell nanoparticles, and others [6]. Nanotechnology is one of the most important areas of research worldwide [7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23]. Using nanotechnology in various research sectors, significant improvements were recorded, with some of these sectors including information, medicine, energy, environmental science, and transport. Nanomaterials and nanoparticles have contributed to the development of modern computing and electronics such as transistors, memory chips, and semiconductors [22; 23]. Through nanotechnology in medicine, researchers have designed and developed nanoparticles and nanomaterials for the prevention, diagnosis, and treatment of different diseases [7; 8]. Researchers have incorporated nanotechnology into solar panels and batteries, and have developed many new, efficient, and renewable energy sources [18; 19; 20]. Engineers have manufactured nanomaterial membranes that clean the contaminants from wastewater [21]. The nanoengineering materials used in the automotive industry have provided innovative solutions to improve transportation infrastructure [24]. The next section will present significant information regarding the most studied nanoparticles for biomedical applications. Magnetic nanoparticles are interesting magnetic nanomaterials, considered a challenge for modern scientific research because of their oxidative sensitivity to other magnetic mixtures; \"superparamagnetic\" are particles that are guided with the help of an external magnetic field, and they can be magnetically stirred to the desired tumor/place. Magnetic particles have significant properties depending on the synthesis methods [4; 5; 25]. Magnetite nanoparticles are used in multiple applications, particularly in biomedicine, because of the magnetic field, the fact that they can carry specific drugs, and that they can support specific receptors to ensure targeting of various tissues, organs, or even cells [26]. Magnetic nanoparticles are also widely used in environmental applications because they can easily be removed from the environment.