Rafael M. Freire

Magnetic Nanosystem for Cancer Therapy Using Oncocalyxone A, an Antitomour Secondary Metabolite Isolated from a Brazilian Plant

This paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series of pharmacological properties: antioxidant, cytotoxic, analgesic, anti-inflammatory, antitumor and antiplatelet. Onco A was associated with magnetite nanoparticles in order to obtain magnetic properties. The components of MO-20 were characterized by XRD, FTIR, TGA, TEM and Magnetization curves. The MO-20 presented a size of about 30 nm and globular morphology. In addition, drug releasing experiments were performed, where it was observed the presence of the anomalous transport. The results found in this work showed the potential of onco A for future applications of the MO-20 as a new magnetic drug release nanosystem for cancer treatment.

Super-Paramagnetic Nanoparticles with Spinel Structure: A Review of Synthesis and Biomedical Applications

The study of ceramic materials has attracted the attention of many researchers due to the possibility of their use in nanotechnology. The spinel ferrites form a large group of materials with a broad range of applications. Some examples include electronic devices such as high-frequency transformer cores, antenna rods, induction-tuners, among many others. However, when the ferritic materials display superparamagnetic behavior, their potential for biological applications like drug delivery, hyperthermia, resonance magnetic imaging and magnetic separation, become amazingly high. Therefore, the superparamagnetism is a characteristic strongly desired for spinel ferrites. Since this phenomenon is size-dependent, the methodologies to synthesize these materials has emerged as a crucial step in order to obtain the desired properties. In this regarding, several synthetic processes have been developed. For example, co-precipitation is a fast and cheap method to synthesize superparamagnetic spinel ferrites. However, methodologies involving microwave, ultrasound or polymers frequently result in these kind of materials. Therefore, this review brings a brief historic introduction about spinel ferrites as well as essential concepts to understand their structure and magnetic properties. In addition to this, recent advances in synthesis and applications of the superparamagnetic spinel ferrites are mentioned. Contents of Paper

Bimagnetic Core/Shell Nanoparticles: Current Status and Future Possibilities

In this chapter, we present recent advances in interface properties, and synthetic approaches to and applications of bimagnetic core/shell nanoparticles (NPs). First, a brief overview of magnetic core/shell architectures is presented. Then we introduce the principles behind magnetic and structural properties. In this connection, interface phenomena such as the proximity effect, exchange coupling, and exchange bias are summarized. Furthermore, the effects of crystal morphology and phase composition on these exchange interactions are discussed. Chemical methods to synthesize bimagnetic core/shell NPs, including thermal decomposition, seed-mediated growth, coprecipitation, and hydro/solvothermal approaches, are presented. Once produced, surface properties of the core/shell architecture need to be modulated since each application has special requirements. Moreover, a section devoted to the surface functionalization of NPs is given. Finally, applications of bimagnetic core/shell NPs in hyperthermia, magnetic resonance imaging, permanent magnets, and magnetic recording data, among other areas, are discussed in more depth.