Illustration: SEM FEG image of magnetite particles – *25 000
Ferromagnetic nanoparticles (Fe3O4) have the particularity to heat by hysteresis when placed in a high-frequency oscillating magnetic field. So when introduced inside cancer cells, they can result in the death of cells containing the nanoparticles if the patient is placed in an oscillating magnetic field. This is an effective physical medium for specifically eliminate cells containing iron oxide. Note that these materials have another useful in clinical biology property like being visible by MRI which allows tracing the migration of cancer cells when the nanoparticles were internalized by the cells.
Human Health: Nanoparticles and bone metastases
Bone metastases are common sites of some types of tumors such as breast cancer and are poor prognosis. They result from the migration of tumor cells in various bone structures. The syntheses of tumor cells activate cells that remove bone tissue and bone metastases are accompanied by localized destruction of bone tissue.
These lesions are often painful and more resistant to chemotherapy and radiotherapy.
The injection of a mineral paste releasing magnetite nanoparticles into the cavity of the metastasis allows physical treatment of bone metastases. Cells destroying bone tissue after activation by tumor cells will reduce the injected inorganic paste and release the magnetite nanoparticles in contact with cancer cells.
TEM: Magnetite particles – *20 000
SEM FEG: Magnetite nanoparticles dispersed in a mineral matrix of calcium sulphate – *6000
Due to their very small size and due to the large capacity of tumor cells phagocytosis, the nanoparticles are concentrated in these last.
When the patient is placed in a high-frequency magnetic field, the nanoparticles will heat up and destroy the cells containing them.
There is furthermore a bystander effect, where the cells are destroyed, nanoparticles are available to be internalized by other cells.