SUMMARY

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The aim of this project is to elaborate and test novel biocompatible magnetic nanoparticles with high heating power for cancer therapy via magnetic hyperthermia technique able to induce cell death in vitro. This involves the realization of  the following objectives:

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Objective 1. Elaboration of magnetic nanoparticles (MNPs) at high temperatures and high pressures with improved hyperthermia capabilities:

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We propose to further extend the polyol based method by performing the synthesis of MNPs at high temperatures, in polyols of different molecular masses, increasing the boiling points of the solvents at high pressure conditions, reaching temperatures in the 200 - 300 °C range. We strongly believe that this approach will enable to highly improve the degree of order of the crystalline structure and to reduce the lattice distortion at the MNPs’ surface (spin canting effect), important features governing the magnetic properties and hence their hyperthermia performance.

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Objective 2. Controlled biofunctionalization of the magnetic nanoparticles with PEG molecules:

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For the successful attachment of PEG molecules to the outer surface of the MNPs two strategies will be employed. In the first one, we will follow a non-covalent approach by introducing in the synthesis mixture PEG molecules of high molecular masses (>1000 g/mol) capable to attach themselves, during the synthesis to the MNPs surface. The second strategy is a post-synthesis approach, implying the use of modified PEG molecules, bearing different anchor groups as carboxylate, phosphate and silane, which are able to bind covalently to the MNPs surface, after they were synthesized.

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Objective 3. Toxicity and cellular uptake of the magnetic nanoparticles:

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In accordance with the recent recommendation of the EU NanoSafety Cluster group, the in vitro evaluation of MNPs toxicity will be done using 4 complementary types of viability assays.  The membrane integrity will be assessed by measuring the release of lactate dehydrogenase (LDH), a stable cytosolic enzyme that is released upon cell lysis. The metabolic activity will be evaluated using two tests, Alamar Blue and quantitation of the ATP respectively. Trypan Blue will be used as a gold standard to validate the results obtained with the previous assays, since it is known that MNPs are able to interfere with the existent viability assays.

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Objective 4. Magnetic hyperthermia capabilities assessment of the magnetic nanoparticles:

 

The impact on the integrity of both normal and cancer cells (unloaded with MNPs) upon exposure to an electromagnetic field (EMF) will be firstly assessed. In particular, we are interested in physical modifications of the cellular local environment and cell viability as a function of both H*f factor and the duration of the exposure. Secondly, the samples containing the cancer cells loaded with the MNPs at concentrations bellow their intrinsic toxicity level (according to objective 3) will be placed inside a coil and exposed to external AC magnetic fields. We will perform a systematic study of the heat released by MNPs inside cells as a function of exposure time, amplitude and frequency of the AC magnetic field (H*f factor) and MNPs’ concentration.