Magnetic nanoparticles
Composite nanoparticles with magnetically and light activated release of biologically active compounds
The project is devoted to the synthesis of composite nanosystems whose magnetic cores based on ferrites will be coated by complex architectures with non-covalently attached biologically active compounds. The functional component of the shell will consist of thermoresponsive polymers with phase transition at 40-50°C combined with hexaferrite nanoplates or gold nanostructures, which will enable specific mechanisms of activation. After application of an alternating magnetic field of suitable parameters, rotational relaxation of the hexaferrite nanoplates or even pronounced heating effect of the ferrite cores will occur, leading to the controlled release of therapeutic agents. Alternatively, the heating effect will be achieved by surface plasmon resonance of the gold nanostructures excited by light in the Vis/NIR region. In addition, the ferrite cores will guarantee strong contrast effect in magnetic resonance imaging (MRI). Physical studies of the nanosystems will be carried out together with studies of biocompatibility and functionality in vitro, with ultimate goal of testing in vivo.
- Czech Science Foundation (2016-2018)
[GA16-04340S]
- Collaboration with Faculty of Science of Charles University and IKEM.
The project is concerned with the development and applications of novel magnetic nanoparticles (MN) of substituted magnetite and epsilon-Fe
2O
3 in biophysical and biomedical research. It aims at contrast increase in MRI, cell internalisation of MN, and optimalisation of parameters for magnetic manipulation. Doped epsilon-Fe
2-xM
xO
3 and Fe
3-xM
xO
4 (M=Ga, Zn, Al, etc.), will be prepared as magnetic cores of various size distributions and shapes, and their magnetic behaviour will be thoroughly analysed. The biochemical properties of MN will be adjusted by coating that will suppress their toxicity and degradability and increase their colloidal stability and provide them with fluorescence. We shall study the effect of magnetic parameters and aggregation of MN cores on MRI contrast and magnetic manipulation of labelled cells. Cytotoxicity and cell internalisation of MN will be investigated with respect to their chemical composition, size, shape, and surface properties. The optimized products will eventually be employed in advanced in vivo studies aimed at magnetic transport and MRI detection.
The project is directed to magnetic oxides of the (La,Sr)MnO3 perovskite type in the form of isolated nanosized crystallites, high-pressure compacts and sintered nanostructured solids. The research relies on a novel method of synthesis enabling to grow particles in high yield, to vary composition gradient between the inner part and surface layer, as well as to form core/shell composites. The manganites are selected in view of their very rich magnetic phase diagram in dependence on the charge carrier doping that can be efficiently controlled by nominal composition, chemical modification of the particle surface and chemisorption of extra oxygen. We plan to characterize the structure and composition of the grown products using X-ray and neutron diffraction, small angle scattering, electron microscopy and energy dispersive spectroscopy. Static and dynamic magnetic properties will be investigated using DC and AC methods and further probed by incorporation of highly anisotropic rare earth cations in the particles in order to distinguish between the intrinsic and surface related effects.
- Ministry of Industry and Trade (2011-2015)
[FR-TI3/521]
Project is focused on the development of technology of new medical preparations leading to an important improvement of diagnostics and therapy, particularly of cancer diseases.
- Czech Science Foundation (2010-2014)
[GAP204/10/0035]
- Collaboration with Faculty of Mathematics and Physics, Charles University
Miniaturization of electronic elements including magnetic ones concentrates interest on systems of magnetic nanoparticles motivated by their broad application potential especially in medicine (increase of MRI contrast, magnetic hyperthermia, targeted transport). The aim of the project is to use the study of hyperfine interactions for elucidation of new specific properties of magnetic nanosystems connected to the growing influence of the surface effects with the decrease of the particle sizes. For this purpose we shall use the combination of NMR with high resolution and Mössbauer Spectroscopy yielding a slightly different spectrum of information. With respect to the isotope specificity of both methods we shall deal with the iron compounds where in particular the nuclei of the stable isotope 57Fe will be the local probe. The decisive role for the successful handling of the project will be the production of required materials – nanoparticles of Fe oxides with the spinel and hexagonal structures including their nanocomposites in various matrices.
- Czech Science Foundation (2011-2014)
[GAP108/11/0807]
- Collaboration with Faculty of Science of Charles University.
The work will be devoted to the preparation and study of complex magnetic nanoparticles with precisely controlled properties, enhanced chemical stability and biocompatible organic corona for biological and biomedical applications, particularly for MRI and magnetically induced hyperthermia. The reliable control of the magnetic properties will be accomplished by monodisperse magnetic cores of various ferrites and La
1-xSr
xMnO
3 manganite with tunable composition and size. These magnetic cores, exhibiting self-controlled heating in AC magnetic field and exceptionally high spin-spin relaxivity, will be coated by the primary silica layer. After formation of highly stable interface the PEG chains will be attached covalently. The extensive characterizations and detailed magnetic measurements will be carried out comparing the results also with the data obtained for polydisperse samples. The magnetic heating and relaxometric studies of the monodisperse nanoparticles will enable the explanation of the heating mechanism and better insight into the spin-spin relaxivity.
- Grant Agency of the Academy of Sciences (2006-2010)
- Collaboration of 10 institutes.
The aim of the project is to develop a new generation of nanopharmaceuticals, i.e. drugs and drug delivery systems both for diagnosis and nanotherapy. Validated analytical techniques are included to confirm the identity,stability and binding to target macromolecules.
- Grant Agency of the Academy of Sciences (2005-2008)
- Collaboration with Institute of Macromolecular Chemistry of the CAS.
The project is aimed on the research of new magnetic nanoparticles for applications in medicine. It covers synthesis of magnetic particles based on mixed magnetic oxides, ferrimagnetic hexagonal ferrites and ferromagnetic manganites of defined properties, their stabilization and preparation of composite magnetic nanoparticles using biocompatible molecules and polymers. The particles surface will be modified to enable immobilization e.g. anticancer drugs. Modification of the resulting properties of the composites will be oriented mainly with respect to future applications, such as magnetic hyperthermia and contrast agents for magnetic resonance imaging (MRI).
