A Magnetic Heating Coil (MHC) has been designed, which has the potential to interact with magnetic Nanoparticles (NPs) to produce local temperature changes. The aim is to design a device capable of studying medically targeted magnetic-fluorescent core-shell NPs (with potential applications in cancer therapy via hyperthermia). Very little is known about how the magnetic-fluorescent NPs respond to magnetic fields and the effect this would have on their optical properties, therefore, considerable work is still required in order to understand the detailed interactions. Several modelling and simulations of the MHC were conducted besides developing the MHC that was designed and built for small samples of NPs (1-10ml volumes). Two different heating coil geometries were examined (coil A and coil B), where the former operates at 83 kHz and the latter operates at 125 kHz. Several tests for fluorescent emission, lifetime and anisotropy with several different NPs samples were conducted. We found that as the temperature increased from 5 °C to 45 °C, the fluorescence lifetime dropped from 3.8 ns to 3.6 ns. Also, the correlation time of the fluorescence in dilute solutions with varying temperatures from 20 °C to 40 °C was investigated, and it was found that decreased from 0.9 ns to 0.6 ns showing that the rotational diffusion of the dye increased and the molecules become more mobile. The MNPs were found to quench the fluorescent emission at high concentrations. Also, the MNPs induce only a small change in a lifetime from 3.9 ns to 3.4 ns. / Libyan Higher Ministry of Education

Yes / The gadolinium-doped iron oxide nanoparticles (GdIONP) with greater specific power adsorption rate (SAR) than Fe3O4 was developed and its potential application in tumour therapy and particle tracking were demonstrated in transgenic adenocarcinoma of the mouse prostate C1 (TRAMP-C1) tumours. The GdIONPs accumulated in tumour region during the treatment could be clearly tracked and quantified by T2-weighted MR imaging. The therapeutic effects of GdIONP-mediated hyperthermia alone or in combination with radiotherapy (RT) were also evaluated. A significant increase in the tumour growth time was observed following the treatment of thermotherapy (TT) only group (2.5 days), radiation therapy only group (4.5 days), and the combined radio-thermotherapy group (10 days). Immunohistochemical staining revealed a reduced hypoxia region with vascular disruption and extensive tumour necrosis following the combined radio-thermotherapy. These results indicate that GdIONP-mediated hyperthermia can improve the efficacy of RT by its dual functions in high temperature (temperature greater than 45 °C)-mediated thermal ablation and mild-temperature hyperthermia (MTH) (temperature between 39 and 42 °C)-mediated reoxygenation.

Laser therapies can provide a minimally invasive treatment alternative to surgical resection of tumors. However, therapy effectiveness is limited due to nonspecific heating of target tissue, leading to healthy tissue injury and extended treatment durations. These therapies can be further compromised due to heat shock protein (HSP) induction in tumor regions where non-lethal temperature elevation occurs, thereby imparting enhanced tumor cell viability and resistance to subsequent therapy treatments. Introducing nanoparticles (NPs), such as multi-walled nanotubes (MWNTs) or carbon nanohorns (CNHs), into target tissue prior to laser irradiation increases heating selectivity permitting more precise thermal energy delivery to the tumor region and enhances thermal deposition thereby increasing tumor injury and reducing HSP expression induction. This research investigates the impact of MWNTs and CNHs in untreated and laser-irradiated monolayer cell culture, tissue phantoms, and/or tumor tissue from both thermal and biological standpoints. Cell viability remained high for all unheated NP-containing samples, demonstrating the non-toxic nature of both the nanoparticle and the alginate phantom. Up-regulation of HSP27, 70 and 90 was witnessed in samples that achieved sub-lethal temperature elevations. Tuning of laser parameters permitted dramatic temperature elevations, decreased cell viability, and limited HSP induction in NP-containing samples compared to those lacking NPs. Preliminary work showed MWNT internalization by cells, which presents imaging and multi-modal therapy options for NT use. The lethal combination of NPs and laser light and NP internalization reveals these particles as being viable options for enhancing the thermal deposition and specificity of hyperthermia treatments to eliminate cancer. / Master of Science

Ryanodine receptor 1 (RyR1) is an isoform of ryanodine receptor predominantly expressed in skeletal muscle. It is a ~2MDa homotetrameric Ca²⁺ release channel with a large cytosolic domain and is in the membrane of the sarcoplasmic reticulum in skeletal muscle cells. RyR1 plays a key role in coordinating excitation-contraction (EC) coupling in skeletal muscle. The activity of the RyR1 channel is regulated by multiple factors, including phosphorylation, oxidation, and ligand binding, all of which tightly control the channel function. The cytosolic domain of RyR1 contains binding sites for these ligands, enabling allosteric regulation. Malignant hyperthermia susceptibility (MHS) is a condition that predisposes individuals to an episode of malignant hyperthermia (MH), a pharmacogenetic shock syndrome triggered by the administration of volatile inhalational anesthetics such as halothane, isoflurane, and succinylcholine. Variants in the RYR1 gene is responsible for over 50% of MHS cases. To treat the rapid metabolic shock that occurs during an MH episode, dantrolene must be administered quickly. Dantrolene, the only approved drug for MH treatment, inhibits RyR1 and reduces Ca²⁺ influx into the cytoplasm of skeletal muscle cells. However, the detailed molecular mechanism by which dantrolene inhibits RyR1 has not been fully elucidated. I purified rabbit RyR1 reconstituted in detergent micelles and subjected the vitrified protein-ligand samples to cryo-electron microscopy (cryoEM) in the presence of dantrolene and other RyR1 agonists, such as ATP, ADP, caffeine, and 4-chloro-m-cresol (4CmC; an MH-triggering molecule). I identified dantrolene binding in complex with ATP or ADP at the RY12 domain on RyR1. Additionally, multiple binding sites for 4CmC on RyR1 were identified. Following the initial characterization of the novel dantrolene and adenosine phosphate binding site in the RY12 domain, purified RyR1 was reconstituted in liposomes for single-channel planar lipid bilayer assays. These assays confirmed that either ATP or ADP is required at the dantrolene binding site for RyR1 inhibition. These findings led us to hypothesize that the novel drug and ATP/ADP binding site in the RY12 domain may also play a physiological role in sensing an increased ADP concentrations in skeletal muscle cells, particularly in the cytosolic compartment during muscle fatigue and pathological conditions. During EC COUPLING, ATP hydrolysis for muscle contraction increases cytosolic ADP concentrations above resting levels. I found that the RY12 site preferentially binds ADP rather than ATP when neither dantrolene nor 4CmC is present. I also discovered that RyR1 forms an endogenous complex with calstabin1 (Cs1, also known as FK506-binding protein 12) and calmodulin (CaM), as observed through cryoEM analysis of rabbit RyR1 solubilized with digitonin and purified by sucrose gradient centrifugation. During these experiments, I noticed that RyR1s in digitonin non-specifically adhere to the air-water interface (AWI) between the sample buffer and atmospheric air on cryoEM grids, resulting in biased orientations of RyR1 particles in the micrographs. To mitigate this effect, glycyrrhizic acid was added to the purified RyR1 sample immediately before vitrification. I applied a similar strategy to prevent the protein from adhering to the AWI when solving the structure of iodinated bovine thyroglobulin (Tg), a ~660 kDa homodimeric soluble protein responsible for thyroid hormone biosynthesis in the thyroid gland. Thyroxines (T4) and iodotyrosines (mono- or di-iodotyrosine) were identified at hormonogenic sites on bovine Tg in the reconstructed EM map, and the analysis around the T4 sites allowed us to hypothesize the molecular mechanism of coupling reactions between two diiodotyrosine residues to synthesize T4 within the Tg molecule.

Doctor of Philosophy / Department of Chemistry / Viktor Chikan / The research work in this thesis aims at investigating the basic physic-chemical properties of magnetic and metal nanoparticles (NPs) for biomedical applications such as magnetic hyperthermia and controlled drug release. Magneto-plasmonic properties of magnetic NPs are important to evaluate potential applications of these materials. Magnetic property can be used to control, monitor and deliver the particles using a magnetic field while plasmonic property allows the tracking of the position of the particles, but aggregation of NPs could pose a problem. Here, the aggregation of NPs is investigated via the Faraday rotation of gold coated Fe[subscript]2O[subscript]3 NPs in alternating magnetic fields. In addition, the Faraday rotation of the particles is measured in pulsed magnetic fields, which can generate stronger magnetic fields than traditional inductive heaters used in the previous experiments. In the second project, the formation of protein-NPs complexes is investigated for hyperthermia treatment. The interactions between gold and iron-platinum NPs with octameric mycobacterial porin A from Mycobacterium smegmatis (MspA) and MspA[superscript])cys protein molecules are examined to assemble a stable, geometrically suitable and amphiphilic proteins-NPs complex. Magnetic NPs show promising heating effects in magnetic hyperthermia to eliminate cancer cells selectively in the presence of alternating magnetic field. As a part of investigation, the heating capacity of a variety of magnetic NPs and the effects of solvent viscosity are investigated to obtain insight into the heating mechanism of these particles. Finally, the controlled drug release of magnetic NPs loaded liposomes by pulsed magnetic field is investigated. The preliminary data indicate about 5-10% release of drug after the application of 2 Tesla magnetic pulses. The preliminary experiments will serve as the initial stage of investigation for more effective magnetic hyperthermia treatment with the help of short magnetic pulses.

by Yuen Wai Fan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 211-232). / Abstracts in English and Chinese. / Acknowledgements --- p.i / List of Publications and Abstracts --- p.ii / Abbreviations --- p.iv / Abstract --- p.xi / Abstract in Chinese --- p.xiv / List of Figures --- p.xvii / List of Tables --- p.xxiii / Contents --- p.xxiv / Chapter Chapter 1. --- General Introduction --- p.1 / Chapter 1.1 --- Hyperthermia --- p.2 / Chapter 1.1.1 --- History of Hyperthermia --- p.2 / Chapter 1.1.2 --- Biological Functions of Hyperthermia --- p.3 / Chapter 1.1.3 --- Clinical Application of Hyperthermia --- p.4 / Chapter 1.1.3.1 --- Whole-body Hyperthermia --- p.4 / Chapter 1.1.3.2 --- Regional Hyperthermia --- p.4 / Chapter 1.1.3.3 --- Local Hyperthermia --- p.5 / Chapter 1.1.4 --- Combination Therapy --- p.5 / Chapter 1.1.4.1 --- Combined treatment with Hyperthermia and Radiotherapy --- p.6 / Chapter 1.1.4.2 --- Combined treatment with Hyperthermia and Chemotherapy --- p.6 / Chapter 1.2 --- Tumour Necrosis Factor --- p.9 / Chapter 1.2.1 --- History of Tumour Necrosis Factor --- p.9 / Chapter 1.2.2 --- Sources of TNF-α and TNF-β --- p.9 / Chapter 1.2.3 --- Biological Roles of TNF --- p.10 / Chapter 1.2.3.1 --- Receptors of TNF-α --- p.11 / Chapter 1.2.4 --- Signaling Pathway of TNF --- p.12 / Chapter 1.2.4.1 --- Activation of Death Domain --- p.12 / Chapter 1.2.4.2 --- Activation of Sphingomyelin Pathway --- p.13 / Chapter 1.2.4.3 --- Activation of NF-kB pathway --- p.13 / Chapter 1.3 --- Types of Cell Death: Necrosis and Apoptosis --- p.16 / Chapter 1.3.1 --- Necrosis --- p.16 / Chapter 1.3.2 --- Apoptosis --- p.16 / Chapter 1.4 --- Signaling Pathway in Apoptosis --- p.19 / Chapter 1.4.1 --- Factors Involved in Apoptotic Pathway --- p.19 / Chapter 1.4.1.1 --- Caspases --- p.19 / Chapter 1.4.1.2 --- Death Substrates --- p.20 / Chapter 1.4.1.3 --- Bcl-2 Protein Family --- p.21 / Chapter 1.4.1.4 --- Role of Mitochondria --- p.23 / Chapter 1.5 --- Objectives of the Project --- p.26 / Chapter Chapter 2. --- Materials and Methods --- p.28 / Chapter 2.1 --- Materials --- p.29 / Chapter 2.1.1 --- Culture of Cells --- p.34 / Chapter 2.1.1.1 --- "TNF-α Sensitive Cell Line, L929" --- p.34 / Chapter 2.1.1.2 --- "TNF-α Resistance Cell Line, L929-11E" --- p.34 / Chapter 2.1.1.3 --- Preservation of Cells --- p.35 / Chapter 2.1.2 --- Culture Media --- p.36 / Chapter 2.1.2.1 --- RPMI 1640 (Phenol Red Medium) --- p.36 / Chapter 2.1.2.2 --- RPMI 1640 (Phenol Red-Free Medium) --- p.36 / Chapter 2.1.3 --- Buffers and Reagents --- p.37 / Chapter 2.1.3.1 --- Preparation of Buffers --- p.37 / Chapter 2.1.3.2 --- Buffer for Common Use --- p.37 / Chapter 2.1.3.3 --- Reagents for Annexin-V-FITC/PI assay --- p.37 / Chapter 2.1.3.4 --- Reagents for Cytotoxicity Assay --- p.37 / Chapter 2.1.3.5 --- Reagents for Molecular Biology Work --- p.38 / Chapter 2.1.3.6 --- Reagents for Western Blotting Analysis --- p.38 / Chapter 2.1.4 --- Chemicals --- p.40 / Chapter 2.1.4.1 --- Recombinant Murine TNF-α --- p.40 / Chapter 2.1.4.2 --- Dye for Cytotoxicity Assay --- p.41 / Chapter 2.1.4.3 --- Fluorescence Dyes --- p.41 / Chapter 2.1.4.4 --- Chemicals Related to Mitochondrial Studies --- p.41 / Chapter 2.1.4.5 --- Inhibitors of Caspases --- p.42 / Chapter 2.1.4.6 --- Antibodies for Western Blotting --- p.42 / Chapter 2.1.4.7 --- Other Chemicals --- p.43 / Chapter 2.2 --- Methods --- p.44 / Chapter 2.2.1 --- Treatment with TNF-α --- p.44 / Chapter 2.2.2 --- Treatment with Hyperthermia --- p.44 / Chapter 2.2.3 --- In vitro Cell Cytotoxicity Assay --- p.45 / Chapter 2.2.4 --- Flow Cytometry --- p.46 / Chapter 2.2.4.1 --- Introduction --- p.46 / Chapter 2.2.4.2 --- Analysis by FCM --- p.48 / Chapter 2.2.4.3 --- Determination of Apoptotic and Late Apoptotic/Necrotic Cells with Annexin-V-FITC/PI Cytometric Analysis --- p.50 / Chapter 2.2.4.4 --- Determination of Mitochondrial Membrane Potential (ΔΨm) --- p.51 / Chapter 2.2.4.5 --- Determination of Hydrogen Peroxide (H202) Release --- p.52 / Chapter 2.2.4.6 --- Determination of Intracellular Free Calcium ([Ca2+]i) Level --- p.52 / Chapter 2.2.4.7 --- Determination of the Relationship of ΔΨm and [Ca2+]i Level --- p.53 / Chapter 2.2.5 --- Western Blotting Analysis --- p.53 / Chapter 2.2.5.1 --- Preparation of Proteins from Cells --- p.53 / Chapter 2.2.5.2 --- SDS Polyacrylamide Gel Electophoresis (SDS- PAGE) --- p.56 / Chapter 2.2.5.3 --- Electroblotting of Proteins --- p.57 / Chapter 2.2.5.4 --- Probing Antibodies for Proteins --- p.57 / Chapter 2.2.5.5 --- Enhanced Chemiluminescence (ECL) assay --- p.58 / Chapter 2.2.6 --- Reverse Transcriptase Polymerase Chain Reaction --- p.58 / Chapter 2.2.6.1 --- Extraction of RNA by Trizol Reagent --- p.59 / Chapter 2.2.6.2 --- Determination of the Amount of RNA --- p.60 / Chapter 2.2.6.3 --- Agarose Gel Electrophoresis --- p.60 / Chapter 2.2.6.4 --- Reverse Transcription --- p.63 / Chapter 2.2.6.5 --- Polymerase Chain Reaction (PCR) --- p.63 / Chapter 2.2.6.6 --- Design of Primers for Different Genes --- p.64 / Chapter 2.2.6.7 --- Determination of the Number of Cycles in PCR for Different Genes --- p.67 / Chapter 2.2.7 --- Caspase Fluorescent Assay --- p.67 / Chapter 2.2.7.1 --- Caspase-3 or ´ؤ8 Assay --- p.67 / Chapter Chapter 3. --- Results --- p.59 / Chapter 3.1 --- Studies of the Characteristics of L929 and L929-11E cells --- p.70 / Chapter 3.1.1 --- Determination of the Growth Curve of L929 and L929-11E Cells --- p.70 / Chapter 3.2 --- Studies on the Effect of TNF-α on L929 and L929-11E Cells --- p.73 / Chapter 3.2.1 --- TNF-α Induced Cell Death in L929 Cells but not in L929- 11E Cells --- p.73 / Chapter 3.2.2 --- TNF-α Induced Apoptosis in a Time-dependent Manner in L929Cells but not in L929-11E Cells --- p.80 / Chapter 3.2.3 --- TNF-α Induced Mitochondrial Membrane Depolarization in a Time-dependent Manner in L929 Cells but notin L929-11E Cells --- p.87 / Chapter 3.2.4 --- TNF-α Induced Cytochrome c Release in a Time- dependent Manner in L929 Cells but not in L929-11E Cells --- p.92 / Chapter 3.3 --- Effect of Hyperthermia on L929 and L929-11E Cells --- p.96 / Chapter 3.3.1 --- Introduction --- p.95 / Chapter 3.3.2 --- Hyperthermia Induced Apoptosis in L929 and L929-11E Cells --- p.96 / Chapter 3.3.3 --- Effect of Hyperthermia on Mitochondrial Membrane Depolarization --- p.100 / Chapter 3.3.4 --- Hyperthermia Induced Cyto c Release in a Time-dependent Manner in L929 and L929-11E Cells --- p.105 / Chapter 3.4 --- Relationship of Hyperthermia and TNF-α with PTP in L929 Cells --- p.107 / Chapter 3.5 --- Effect of TNF-α and Hyperthermia on the Level of Hydrogen Peroxide (H202) in L929 and L929-11E Cells --- p.114 / Chapter 3.5.1 --- Introduction --- p.114 / Chapter 3.5.2 --- TNF-α Enhanced the Level of H202 in L929 cells but not in L929-11E Cells --- p.115 / Chapter 3.5.3 --- Hyperthermia Enhanced the Level of H202 in L929 and L929-11E cells --- p.117 / Chapter 3.6 --- Effect of TNF-α and Hyperthermia on the Level of Intracellular Calcium in L929 and L929-11E Cells --- p.122 / Chapter 3.6.1 --- Increase in the Intracellular Calcium Level Induced by TNF-α Was Related to the Mitochondrial Membrane Depolarization in L929 Cells but not in L929-11E Cells --- p.122 / Chapter 3.6.2 --- Hyperthermia Increased the Level of [Ca2+]i in L929 and L929-11E Cells in a Time-dependent Manner --- p.124 / Chapter 3.7 --- Effect of Combined Hyperthermia and TNF-α Treatment on the Induction of Apoptosis in L929 and L929-1 1E Cells --- p.129 / Chapter 3.7.1 --- Combined Treatment with Hyperthermia and TNF- α Induced Apoptosis in Both L929 and L929-11E cells --- p.129 / Chapter 3.7.2 --- Hyperthermia and Its Combined Treatment with TNF-α Induced Mitochondrial Membrane Depolarization in L929 and L929-11E Cells --- p.135 / Chapter 3.8 --- Investigation of the Downstream Apoptotic Pathway in L929 and L929-11E Cells Upon Hyperthermia and TNF-a treatment --- p.142 / Chapter 3.8.1 --- Introduction --- p.142 / Chapter 3.8.2 --- Effect ofTNF-α and Hyperthermia on p53 Expression --- p.142 / Chapter 3.8.3 --- Effect of Hyperthermia and TNF-α on PARP --- p.146 / Chapter 3.8.4 --- Effect of Hyperthermia and TNF-α on Caspase-3 Activity --- p.149 / Chapter 3.8.5 --- Effect of Hyperthermia and TNF-α on Bid protein --- p.158 / Chapter 3.8.6 --- Effect of Hyperthermia and TNF-α on Caspase-8 Activity --- p.165 / Chapter 3.8.7 --- Effect ofTNF-α on TNFR1 Expression --- p.169 / Chapter Chapter 4. --- Discussion / Chapter 4.1 --- TNF-α Induced Apoptosis and Changed the Mitochondrial Activities in L929 Cells --- p.176 / Chapter 4.2 --- L929-11E cells Possessed Resistance Towards TNF-α --- p.187 / Chapter 4.3 --- Hyperthermia Triggered Apoptosis and Changed Mitochondrial Activities in L929 and L929-11E cells --- p.190 / Chapter 4.4 --- Combined hyperthermia and TNF-α treatment induced cell death and changed mitochondria activities in L929 and L929-11E cells --- p.195 / Chapter 4.5 --- Reversal of the TNF-α resistance and Enhancement of Sensitivity Towards Hyperthermia in L929-11E cells --- p.197 / Chapter 4.6 --- Proposed Pathway in the TNF-α- and Hyperthermia-mediated Apoptosis --- p.200 / Chapter 4.7 --- Application of TNF-α and Hyperthermia on Clinical Cancer Treatment --- p.203 / Chapter Chapter 5. --- Future Perspective of the Project --- p.206 / References --- p.210

[pt] Estudos com nanopartículas magnéticas têm sido realizados no âmbito da medicina tanto para tratamento de tumores e câncer, quanto para fins de diagnósticos ou ainda para transporte de fármacos. Nanopartículas magnéticas podem ser administradas a alvos específicos e mantidas no local adequado por meio de um campo magnético aplicado. Com este propósito, as nanopartículas com um núcleo de material magnético são recobertas com material adequado para sua funcionalização. Neste trabalho sintetizamos nanopartículas de óxido de ferro e funcionalizamos sua superfície com uma bicamada que permitiu criar um compartimento adequado à solubilização de fármacos hidrofóbicos. Nesse compartimento foi solubilizada uma ftalocianina que se mostrou promissora como fotossensibilizante em terapia fotodinâmica. Fotossensibilizantes são moléculas que, ao interagir com a luz, formam espécies altamente reativas, como o oxigênio singlete, que destroem células e tecidos adjacentes. Este processo é utilizado em Terapia Fotodinâmica (PDT). A geração de oxigênio singlete pela ftalocianina no compartimento hidrofóbico foi avaliada usando como sonda o 1,3-difenil isobenzofurano (DPBF), em formulações com os surfactantes não iônicos, Tween 80 e Pluronic 127. Com o objetivo de controlar a liberação de fármacos, construímos um circuito eletrônico para produzir um campo magnético AC que atua sobre as partículas magnéticas e produz um aumento local de temperatura. O aumento de temperatura modifica a difusão das moléculas localizadas na camada que recobre as nanopartículas, o que permite variar a taxa de liberação. Foi estudada a variação de temperatura produzida na presença do campo magnético AC. Foi estudado também o efeito da temperatura na produção de oxigênio singlete. / [en] Magnetic nanoparticles have been studied aiming at medical applications, such as treatment of tumors and cancer, for diagnostic purposes and drug delivery. Magnetic nanoparticles can be administered to specific targets and maintained in the proper location by means of an applied magnetic field. For this purpose, nanoparticles with a core of magnetic material are coated with suitable material for functionalization. In this work, we synthesized nanoparticles of iron oxide and functionalized their surface with a bilayer that served as an appropriate compartment for hydrophobic drugs. A promising phthalocyanine derived photosensitizer was solubilized in this compartment. Photosensitizers are molecules that interact with light to form highly reactive species such as singlet oxygen, which destroy cells and surrounding tissues. This process is used in photodynamic therapy (PDT). The generation of singlet oxygen by the phthalocyanine in the hydrophobic compartment was evaluated using the probe 1,3- diphenyl isobenzofuran (DPBF) in formulations with the nonionic surfactants Tween 80 and Pluronic F-127. Aiming to control the release of drugs, we build an electronic circuit to produce an AC magnetic field which acts on the magnetic particles to produce a local temperature increase. This increase in temperature modifies the diffusion of molecules at the surface layer of the nanoparticles, and allows to control the rate of release. Temperature variation produced in the presence of the AC magnetic field was studied. The effect of temperature on the singlet oxygen production was also studied.

La synthèse de nano-object connait un essor grandissant depuis ces 20 dernières années. Les études fondamentales de système a permis (et permet encore) de trouver de nombreux domaines d'application aux nanotechnologies, que ces soit en catalyse, en électronique, dans le domaine biomédical...La thèse se déroule autour de deux axes de recherches: la synthèse et la description des propriétés magnétique de nanoparticules de fer stabilisé par des liquides ioniques, et la synthèse, l'étude magnétique, et leur évaluation en tant qu'agent de contraste et médiateur d'hyperthermie de nanoparticules de de ferrite fonctionnalisé par des dérivées carbohydrates. / The synthesis of nano-object is growing in the last 20 years. Basic research system has (and still allows) to find many areas of application for nanotechnology that is in catalysis, electronics, biomedical ...The thesis proceeds along two lines of research: the synthesis and the description of magnetic properties of iron nanoparticles stabilized by ionic liquids, and the synthesis, magnetic study, and their evaluation as a contrast agent and hyperthermia mediator of functionalized carbohydrate derivatives ferrite nanoparticles.

Dans les domaines de l’imagerie médicale et la thérapie, l’utilisation des nanoparticules est spécialement attrayante et prometteuse. Il est possible de concentrer dans une même particule plusieurs fonctions complémentaires comme la détection, le ciblage mais aussi la thérapie. Cette multifonctionnalité présente de nombreux avantages, et favorise le développement de nanoparticules pour une thérapie ciblée et guidée par l’imagerie.C’est dans ce contexte d’intense activité centrée sur le développement des nanoparticules pour les applications médicales (imagerie et/ou thérapie) que s’est déroulé mon travail de thèse qui s’inscrit dans la continuité des travaux de Christophe Alric et de Pierre Hugounenq. Ils ont développé respectivement des nanoparticules d’or multifonctionnelles (Au@DTDTPA) et des nanofleurs d’oxyde de fer (γ-Fe2O3).Les nanoparticules d’or (Au@DTDTPA) présentent un effet radiosensibilisant et se comportent comme agent de contraste pour l’IRM (après marquage par Gd3+ rendu possible par les propriétés chélatantes de la couche organique DTDTPA) ou comme radiotraceurs après radiomarquage (le DTDTPA forme des complexes stables avec 99mTc et 111In). Le caractère superparamagnétique des nanofleurs d’oxyde de fer confèrent à ces objets la capacité à rehausser le contraste négatif des images et à induire un échauffement sous l’action d’un champ magnétique alternatif de haute fréquence.L’objectif principal de ma thèse consistait à assembler ces deux types de nanoparticules afin de créer un objet nanométrique combinant les propriétés complémentaires des nanoparticules d’or et des nanofleurs d’oxyde de fer. Dans un premier temps, les conditions optimales de greffage des nanoparticules d’or sur les nanofleurs ont été déterminées. Nous avons montré que de tels agents présentaient après injection intraveineuse une biodistribution adaptée comme le révèlent les images acquises en IRM (grâce aux propriétés magnétiques des nanofleurs) et en TEMP (grâce au radiomarquage de la couche des nanoparticules d’or). En outre ces objets présentent un caractère radiosensibilisant qui est mieux exploité que celui des nanoparticules d’or entrant dans la composition de ces nanofleurs dorées. Associé au pouvoir chauffant des nanofleurs, le pouvoir radiosensibilisant des nanofleurs dorées a conduit à une forte inhibition de la croissance tumorale quand le traitement de rats portant un mélanome combine hyperthermie magnétique et radiothérapie après injection intratumorale des nanofleurs dorées.En conclusion, le travail réalisé au cours de cette thèse a mis en évidence l’intérêt de combiner les nanoparticules d’or et les nanofleurs d’oxyde de fer pour traiter des tumeurs solides par thérapie guidée par imagerie. / In the fields of medical imaging and therapy, the use of nanoparticles is especially attractive and promising. It is possible to concentrate in the same particle several complementary functions such as detection, targeting but also therapy. This multifunctionality has many advantages and promotes the development of nanoparticles for targeted therapy and guided by medical imaging.It is in this context of intense activity focused on the development of nanoparticles for medical applications (imaging and/or therapy) that my thesis work was carried out which is in continuity with the work of Christophe Alric and Pierre Hugounenq. They developed multifunctional gold nanoparticles (Au@DTDTPA) and iron oxide nanoflowers (γ-Fe2O3), respectively.The gold nanoparticles (Au @ DTDTPA) exhibit a radiosensitizing effect and behave as a contrast agent for MRI (after labeling with Gd3 +, made possible by the chelating properties of the organic layer DTDTPA) or radiotracers after radiolabelling (DTDTPA forms stable complexes with 99mTc and 111In). The superparamagnetic nature of the iron oxide nanoflowers gives these objects the ability to enhance the negative contrast of the images and to induce heating under the action of an alternating magnetic field of high frequency.The main objective of my thesis was to assemble these two types of nanoparticles in order to create a nanometric object combining the complementary properties of gold nanoparticles and iron oxide nanoflowers. In a first step, the optimal conditions for grafting gold nanoparticles on the nanoflower were determined. We have shown that, after intravenous injection, these agents exhibit a suitable biodistribution, as revealed by MRI images (thanks to the magnetic properties of nanoflowers) and SPECT (thanks to the radiolabeling of the gold nanoparticle layer). Moreover, these objects have a radiosensitizing character which is better exploited than that of the gold nanoparticles in the golden nanoflowers. Associated with the heating power of nanoflower, the radiosensitizing potential of golden nanoflowers has led to a strong inhibition of tumor growth when the treatment of rats carrying melanoma combines magnetic hyperthermia and radiotherapy after injection of golden nanoflower.In conclusion, the work carried out during this thesis has highlighted the value of combining gold nanoparticles and iron oxide nanoflowers to treat solid tumors by imaging-guided therapy.

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Ou seja, terá que alterar o que aparece nesse campo já registrado automático pelo programa, como: pontuação o sobrenome todo em maiúsculo, etc. on 2014-09-19T13:22:35Z (GMT) / Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-09-19T19:22:41Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) DISSERTAÇÃO REVISÃO FINAL.pdf: 1776163 bytes, checksum: 9cc893b53fed44267523efd8f741e790 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-09-19T19:33:51Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) DISSERTAÇÃO REVISÃO FINAL.pdf: 1776163 bytes, checksum: 9cc893b53fed44267523efd8f741e790 (MD5) / Made available in DSpace on 2014-09-19T19:33:51Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) DISSERTAÇÃO REVISÃO FINAL.pdf: 1776163 bytes, checksum: 9cc893b53fed44267523efd8f741e790 (MD5) Previous issue date: 2013-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work describes the development and characterization of magnetic solid lipid nanoparticles (SLNMP) containing paclitaxel for magnetohyperthermia applications. Magnetic nanoparticles were prepared by coprecipitation of Fe(II) and Fe(III) salts in an alkaline medium. SLNMP containing paclitaxel were prepared by emulsification – solvent diffusion. Characterization of the nanostructured system included morphology analysis, average diameter and size distribution, encapsulation efficiency for paclitaxel, stability and magnetic properties of magnetometry and magnetohyperthermia. Magnetic SLNMP containing paclitaxel exhibited an average diameter of 200nm with a polydispersity index of 0,189; which was confirmed by Atomic Force Microscopy. Stability studies conducted with lyophilized samples showed a decrease of approximately 15% in the amount of encapsulated paclitaxel in 30 days. Magnetometry data confirmed the superparamagnetic behavior of the nanocarriers and magnetohyperthermia effect was demonstrated by an increase of 25°C of the temperature of the nanocarrier. A three fold increase in the drug release rate was obtained when the temperature was raised from 25 to 43°C in the in vitro release assay. This indicated that temperature increase acts as a trigger mechanism for drug release, allowing the preparation of nanostructured controlled drug delivery systems controlled by magnetohyperthermia. / Este trabalho descreve o desenvolvimento e caracterização de nanopartículas lipídicas sólidas magnéticas contendo paclitaxel para aplicação em magnetohipertermia. Nanopartículas magnéticas foram obtidas pelo método de coprecipitação de sais de Fe(II) e Fe(III) em meio alcalino. Nanopartículas lipídicas sólidas magnéticas contendo paclitaxel foram preparadas pelo método de emulsificação-difusão de solvente. O sistema nanoestruturado foi caracterizado quanto à morfologia, diâmetro médio e distribuição de tamanho, eficiência de encapsulação do paclitaxel, estabilidade e propriedades magnéticas de magnetometria e magnetohipertermia. As nanopartículas lipídicas sólidas magnéticas contendo paclitaxel apresentaram diâmetro médio de aproximadamente 200nm com índice de polidispersão de 0,189 e 67% de eficiência de encapsulação do PTX. O estudo de estabilidade realizado em amostras liofilizadas mostrou redução de aproximadamente 15% do paclitaxel encapsulado no período de 30 dias. Pelo estudo de magnetometria os nanocarreadores apresentaram curva de magnetização condizente com material em regime perparamagnético e o efeito de magnetohipertermia foi verificado pelo aumento da temperatura de aproximadamente 25ºC do nanocarreador.A taxa de liberação do paclitaxel foi aumentada em 3 vezes quando a temperatura foi elevada de 25ºC para 43ºC no ensaio de liberação in vitro indicando que o aquecimento dos nanocarreadores pode representar um mecanismo desencadeador do processo de liberação do fármaco, possibilitando a obtenção de sistemas de liberação controlada por magnetohipertermia.