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Systematic study of the experimental conditions for a new aqueous medium route to synthesize magnetite nanoparticles with enhanced hyperthermic properties

Grant number: 16/20429-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): January 01, 2017
Effective date (End): December 31, 2017
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Laudemir Carlos Varanda
Grantee:Beatriz Montilha Tirich
Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

The magnetic hyperthermia is emerging as one of the most promising noninvasive treatments for the different cancer types. The magnetic nanoparticles when exposed to alternating magnetic field with appropriate intensity and frequency, can absorb energy by different processes and dissipate it as heat. The most widely used measurement parameter used to evaluate the effective conversion rate is called SAR (Specific Adsorption Rate). However, the efficient response for that process requires that the nanoparticles show a set of properties which comprises: high saturation magnetization, the superparamagnetic behavior, high dispersibility in physiological environment and appropriate morphological parameters, i.e., narrow particle size distribution and controlled shape. In recent years, magnetic nanoparticles with strict control of size and shape has been successfully synthesized in organic solvents by thermal decomposition processes, which makes dispersion in an aqueous medium leading to lengthy and expensive surface ligand exchange processes. Recently, some studies in the literature have shown that the optimized conversion rate (SAR) seems to involve magnetic nanoparticles with size in the superparamagnetic behavior, but in a size limit that comprises the mono to multidomains magnetic transition. Our research group has tested and developed a new route for the synthesis of magnetic nanoparticles in aqueous medium that meet the needs in relation to magnetic and morphological properties. However, this methodology needs to be systematically studied to optimize the synthesis conditions in order to promote the maximum SAR for this nanoparticle system. In this project, we propose to study the experimental variables such as time, temperature, concentration and ratio of reactants, and stirring (time and type). The proposed methodology is based on the formation of magnetite nanoparticles by the controlled hydrolysis and reduction of iron(III) ions in an aqueous medium using the sulphite ions with controlled reducing agent. The method is simple and innovative and with the possibility of large-scale production, but must be optimized to ensure the reproducibility and quality of properties. After synthesis of the nanoparticles, it will be characterized, stabilized in physiological environment and evaluated against their hyperthermic properties. (AU)