Multimodal magnetic nanostructures

THESIS 9290The objectives of this thesis are to develop new iron oxide and cobalt ferrite (CoFe2O4) based nanocomposites and their fluorescent-magnetic derivatives with a range of potential biomedical applications. The major aims are: (i) to prepare magnetic iron oxide based nanoparticles and nanocomposites by co-precipitation techniques using Deoxyribonucleic acid (DNA) and various polyelectrolytes as stabilisers; (ii) produce new stable magnetic fluids based on functionalised iron oxide nanoparticles for Magnetic resonance imaging (MRI) and other potential biomedical applications; (iii) to develop new "two-in-one" fluorescent/magnetic nanocomposites using magnetic nanoparticles and fluorescent dyes or Quantum dots (QDs) for intracellular visualisation, manipulation and diagnostics; (iv) to characterise the nanoparticles, nanocomposites, and magnetic fluids fully using different instrumental techniques (e.g. Transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), Raman, Ultraviolet-visible spectrophotometry (UV-vis), photoluminescence spectroscopy (PL), X-ray powder diffraction (XRD), Photon Con-elation Spectroscopy (PCS), Thermogravimetric analysis (TGA), Nuclear Magnetic Resonance Dispersion (NMRD), magnetisation measurements (SQUID)

Biomimetic Synthesis of Hierarchically Porous Nanostructured Metal Oxide Microparticles—Potential Scaffolds for Drug Delivery and Catalysis

International audienceHierarchically porous hybrid microparticles, strikingly reminscent in their structure of the silica skeletons of single-cell algae, diatoms, but composed of titanium dioxide, and the chemically bound amphiphilic amino acids or small proteins can be prepared by a simple one-step biomimetic procedure, using hydrolysis of titanium alkoxides modified by these ligands. The growth of the hierarchical structure results from the conditions mimicking the growth of skeletons in real diatoms—the self-assembly of hydrolysis-generated titanium dioxide nanoparticles, templated by the microemulsion, originating from mixing the hydrocarbon solvent and water on action of amino acids as surfactants. The obtained microsize nanoparticle aggregates possess remarkable chemical and thermal stability and are promising substrates for applications in drug delivery and catalysis. They can be provided with pronounced surface chirality through application of chiral modifying ligands. They display also high selectivity in sorption of phosphorylated biomolecules or medicines as demonstrated by 1H and 31P NMR studies and by in vitro modeling using 32P-marked ATP as a substrate. The release of the adsorbed model compounds in an inert medium is a very slow process directed by desorption kinetics. It is enhanced, however, noticeably in contact with biological fluids modeling those of the tissues suffering inflammation, which makes the produced material highly attractive for application in medical implants. The developed synthetic approach has been applied successfully also for the preparation of analogous hybrid microparticles based on zirconium dioxide or aluminum sesquioxide