Micro et nanoparticules pour des applications biotechnologiques : fabrication de nanoparticules par copolymère dibloc pour l’imagerie médicale ; destruction de cellules cancéreuses par vibrations magnéto-mécaniques de microparticules magnétiques

Abstract : Magnetic nanoparticles are now used in a wide range of applications such as diagnostic, therapeutics or more recently theranostics. The numerous and diverse fabrication processes allow the fabrication of a wide range of nanoparticles in terms of size, shape, material and magnetic properties. An ideal fabrication process would allow the simple and cheap fabrication of a great quantity of monodisperse nanoparticles. In this objective, the first part of this work will be focused on a new and original fabrication process based on the combination of a “top-down” and “bottom-up” approach. The idea relies on the special auto organization properties of a diblock copolymer: one of the two phases has the ability to self organize into vertical cylinders in the matrix of the other polymer, provided that the annealing conditions are favourable. The selective etching of the cylinders leads to a mask of holes in a polymer matrix. Then, the deposit of a magnetic material and the etching of the polymer matrix leads to the formation of a hexagonal network of nanoparticles attached to the substrate. If the substrate is composed of a sacrificial layer, the nanoparticles can be released in a solution. The structural and magnetic properties of theses nanoparticles fabricated via a PS-PMMA template will be studied. Their characterization will show that the process is still to be optimized but allows already to obtain monodisperse superparamagnetic nanoparticles.A second part focuses on another biomedical applications of magnetic particles: the cancer treatment. A new technique, which is an alternative to the existing methods such as hyperthermia or drug delivery, was first proposed by the Argonne National Laboratory (2010) and taken over at Spintec (2011). The idea is to reactivate the apoptosis (programmed cell death) of cancer cells via the magneto mechanical vibrations of magnetic microparticles attached to their membranes. It was proved that weak external magnetic fields (30mT at 20Hz) applied on permalloy disks in a vortex configuration lead to a significant increase of the apoptotic rate of cancer cells. In the objective of making this method possible for clinical applications, biocompatible magnetite microparticles were fabricated via the same fabrication process than the permalloy disks (optic lithography). Their structural and magnetic properties are compared, as well as their behavior in a suspension and their lethal effect on cancer cells via the application of an external magnetic field. For now, the permalloy microdisks provide better results than the magnetite particles. Some parameters of the experimental set up have to be optimized for the magnetite particles, such as the amplitude of the applied magnetic field. However, the first effects observed with the magnetite particles are quite promising.
Complete list of metadatas

Cited literature [165 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01292065
Contributor : Abes Star <>
Submitted on : Tuesday, March 22, 2016 - 3:05:26 PM
Last modification on : Thursday, April 4, 2019 - 9:44:02 AM
Long-term archiving on: Monday, November 14, 2016 - 2:06:02 AM

File

MORCRETTE_2015_archivage.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01292065, version 1

Collections

Citation

Mélissa Morcrette. Micro et nanoparticules pour des applications biotechnologiques : fabrication de nanoparticules par copolymère dibloc pour l’imagerie médicale ; destruction de cellules cancéreuses par vibrations magnéto-mécaniques de microparticules magnétiques. Biophysique [physics.bio-ph]. Université Grenoble Alpes, 2015. Français. ⟨NNT : 2015GREAY052⟩. ⟨tel-01292065⟩

Share

Metrics

Record views

788

Files downloads

1967