Evaluation of Hyperthermia Using Magnetic Nanoparticles and Alternating Magnetic Field

Résumé: Pendant des années, l'élévation de la température du corps, connu sous le nom d'hyperthermie, a été utilisée pour traiter les cellules cancéreuses. L'hyperthermie peut être atteinte via diverses méthodes invasives et non invasives, dont certaines sont pratiquées au niveau de la recherche clinique, et certaines autres ont déjà atteint l'approbation pour la pratique en clinique. Les nanoparticules magnétiques (NPM) peuvent générer de la chaleur et donc chauffer leur entourage une fois qu'ils sont placés dans un champ magnétique alternatif. Contrairement aux autres méthodes d'hyperthermie, l'hyperthermie par NPM utilisant un champ magnétique alternatif fournit un contrôle avancé et peut avoir un effet très localisé. En plus, les NPM ont un énorme potentiel pour les applications biomédicales d'imagerie, de diagnostic et de traitements. En plus, les NPM peuvent être propulsées par les gradients magnétiques vers un emplacement désiré du corps. La propulsion et le contrôle et l'hyperthermie permettent l'introduction d'un système robotique miniaturisé pour les applications thérapeutiques localisées. En effet, une fois chargé avec des agents thérapeutiques, les NPM peuvent être propulsés, ciblés vers l'organe malade et ensuite chauffés utilisant des champs magnétiques alternatifs qui induira une séquence d'actionnement des médicaments. Dans ce mémoire, les attributs physiques des NPM tels que l'aimantation, les domaines magnétiques, l'hystérésis, la relaxation et ainsi que divers mécanismes de chauffage sont étudiés. Aussi les limites biologiques qui permettent de déterminer la fréquence et l'intensité des champs magnétiques alternatifs utilisés pour l'hyperthermie sont expliquées.----------Abstract: Elevation of body temperature otherwise known as hyperthermia, has been used to treat concerous cells for many decades. Hyperthermia can be achieved via various invasive and non-invasive methods, some of which are being practiced at clinical levels, and some others have already reached clinical trials. Magneric nanoparticles (MNP) can generate heat and thus heat their surroundings once they are placed in an alternating magnetic field (AC magnetic field). In contrast to other hyperthermia methods, hyperthermia via MNP in an AC magnetic field provides advanced control and can be highly localized. In addition, MNP have enormous potential in biomedical applications such as imaging, medical diagnosis and treatment. Also, agglomeration of MNP can be propelled with an inhomogeneous magnetic field towards a desired location. The propulsion, control and hyperthermia allow the introduction of a miniaturized robotic system. Indeed, MNP micro-carriers loaded with therapeutic agents can be propelled and tracked to a hyperthermia and drug actuation sequence. In this thesis, the physical attributes of the MNP such as the magnetization, magnetic domains, hysteresis, and relaxations as well as various heating mechanisms are discussed. Also biological limits that determine the frequency and the intensity of AC magnetic fields used for hyperthermia are explained

Stabilization of Aqueous Template-Based Functionalized Magnetic Nanoparticles

Magnetic particles have attracted increasing attention in fields ranging from separation processes to electromagnetic information storage an medical application. Various approaches for their synthesis have been developed and studied to satisfy the criteria of production. Improvement and optimization of size, stability, and functionality is of vital importance in biological applications. The main aspect of project, initially, was to study the application of aqueous functionalized magnetic nanoparticles coupled with high gradient magnetic separation technique for the removal of trace residue of organic contaminants from drinking water. However, the importance of synthesizing stable ferrofluid for this purpose became clear later and took precedence over the initial objective. Different approaches were adopted, such as the incorporation of poly(ethylene glycol) methacrylate, ethylenediamine, and chitosan, to enhance the stability of magnetic particles. However, these surface modifications had unfavorable effect on the stability of initial particles. In accord with the initial objective of the project, the possibility of utilization of β-cyclodextrin, as organic pollutant entrapment agent, was investigated in preliminary studies conducted on its interaction with a model compound, procaine hydrochloride. The outcomes of these experiments suggest its potential as a biocompatible removal agent for the elimination of organic pollutant in drinking water system, or other applications that require selective separation of organic compounds

Nanomaterials for Biomedical and Biotechnological Applications

The need for constant improvement to reach a high standard of safety and to make nanomaterials accessible for marketing has generated a considerable number of scientific papers that highlight new important aspects to be considered, such as synthesis, stability, biocompatibility, and easy manipulation. In order to provide a comprehensive update on the latest discoveries concerning nanomaterials, this reprint presents 14 scientific papers, 10 research articles and 4 reviews, that deal with biomedical and biotechnological applications of nanomaterials